Manipulation of intercropping technology for conservation of predaceous ladybird beetles (Coleoptera: Coccinellidae) to aphids (Hemiptera: Aphididae) management

Manipulation of intercropping technology for conservation of predaceous ladybird beetles (Coleoptera: Coccinellidae) to aphids (Hemiptera: Aphididae) management | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Manipulation of intercropping technology for conservation of predaceous ladybird beetles (Coleoptera: Coccinellidae) to aphids (Hemiptera: Aphididae) management Muhammad SARWAR This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6794268/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 5 You are reading this latest preprint version Abstract Experiments were made on the feasibility of canola-based maize intercropping to observe population and conservation of aphidophagous ladybird beetles and their ultimate impacts on aphid’s density and crop yield. Experimental treatments were, canola 4 rows+ maize single row, canola 4 rows+ maize double row intercropping, and their comparison with canola and maize grown alone to generate data whether these combinations had encouraging or discouraging influences on useful and harmful insect populations. The striking result of this study was impacts of maize intercropping to enhance predators and suppress the pests populations. Data on populations of aphid and maize borer had shown significantly more numbers of pests noted in treatment of canola and maize, respectively, planted alone compared to canola intercropped with double rows of maize. Double lines of maize plus canola intercropping gave better results than single line for holding higher predator populations. Results achieved indicated that canola and double row maize intercropping generated better conservation of coccinellid beetles for aphid or borer control than single row maize and check treatment, and yielded higher produce. This could be attributed due to the capacity of double row maize planting to hold maximum numbers of ladybird beetles and their more severe competition to predate upon the pests prey. And owing to low level of pest populations on intercropped canola and maize plantings, these produced significantly higher seed yields. The predominant emerging observation was that the intercropped maize exhibited proficient shelter and roosting sites for coccinellids during peak winter season, which was a remedy against hibernation and dispersion constraints upon these predators. Based on the outcomes made during current experiment, the implications of existing knowledge and prospects would facilitate implementation of intercropping strategy to enhance suppression of insect pests. Aphid. Canola. Maize. Coccinellid. Conservation. Intercropping Introduction Aphids ( Homoptera : Aphididae ) are major insect pests of crops; they feed specifically with their slender mouthparts and cause damage by draining plant nutrients (Sarwar 2017; Sarwar et al. 2011). They posture a momentous menace to worldwide crops production and are also major vectors of certain plant viruses (Ng and Perry 2004). Plants have established protecting compounds known as phenolics, alkaloids, terpenoids, a well as sulfur and nitrogen containing metabolites, which display favorable features against aphids, such as aphicidal and antifeedant, thus disturbing persistence fitness. Plants react to aphid invasion by activating defense genes that lead to the creation of physical hurdles and lethal chemicals (direct resistance). Additionally, attacked plants can appeal to natural enemies of aphids by liberating particular volatile compounds (indirect resistance) (Farhan et al. 2024). The green peach aphid, Myzus persicae (Sulzer), is a polyphagous pest on over 400 plant species in more than 50 families. Phenotypic plasticity of individuals and genetic variability in the population presumably contribute to this polyphagy (Weber 1985). Liyun and Gexia (2006) reported 70 species of aphids and their host plants include 58 genera. The importance of oilseed rape ( Brassica napus Linnaeus) as a source of industrial and nutritional oil has been increasing worldwide. In many regions, the increase in its acreage was accompanied by a dramatic and disproportionate increase of pesticide uses because oilseed rape is attacked by a range of pest species (Alford et al. 2003). Mussury and Fernandes (2002), observed aphids’ population from initial stage of canola [rape] plant development to senescence. Aphids were more abundant during the flowering phase, and they usually located in the stems of the inflorescence and developing fruits. The yield of this crop however, can be substantially increased to a greater extent by adopting suitable plant protection measures. Undoubtedly, due to harmful effects of toxic pesticides and intensive trend for research into biological control, today there is a critical need for alternatives to chemical control. The ladybird beetles belong to the family Coccinellidae of order Coleoptera and the members of this family are exclusively predators on small soft bodied insect pests (Omkar and Pervez 2000). The Cheilomenes sexmaculata (Fabricius), an aphidophagus coccinellid, feeds on pests, but also feeds upon non-aphid hosts. High values of life history parameters, viz., developmental rate, immature survival, fecundity, egg viability, reproductive rate, conversion efficiency of ingested food, fecundity after single mating and intrinsic advantages of C. sexmaculata over the Coccinella species have been studied (Omkar et al. 2005). The lady beetle Coccinella septempunctata Linnaeus, is an important predator of aphids in arable crops (Bianchi and Werf 2003). Cabral et al. (2009) showed Coccinella undecimpunctata Linnaeus, to be an effective predator for the biological control of M. persicae , and the presence of both 4 th instar larvae and adults of this ladybird beetle could increase the efficiency in field pest suppression. These predators predate upon many species of aphids, mites, scale insects, aleyrodids, mealy bugs and citrus pryllid (Nayar and Krishnan 1989). Unfortunately, these coccinellids meet resistances from a number of environmental variations, for instance, as days get shorter and temperatures fall, ladybird beetles seek shelter behind bark, under leaves or in other protected locations, and such requirements of the adults may limit their potential as biocontrol agents in field (Sarwar 2016a). Hagen (1962) pointed out the phenomenon of hibernation in many coccinellids; while, Solbreck (1974) examined the coccinellid adults hibernating in large aggregations in grass and dead leaves accumulated at the bases of large trees. This microhabitat provided insulation against fluctuating temperature, but despite of those adaptations, mortality at hibernation sites was high. Wright and Laing (1982) found differing mortality rates between 6.8% and 57% in coccinellids. Felland and Hull (1996) determined the spatial and temporal distribution of lady beetles in all available ground cover habitats and surrounding refuges. Density of over wintering adults was noted at peak in the autumn and declined in the spring. Studies on influences of these factors on the activity of these predators can be helpful in understanding the ways in which such insects could survive in their natural habitats. As a result, devising approaches and strategies for the utilization and conservation of natural enemies as biocontrol agents sparked my interest in studying conservation of predaceous lady beetles. For the enhancement of biological control, the encouragement of the natural enemy has always been an attractive idea to the entomologists. The important approach would be to modify the environment in such as way that any adverse environmental effects could be altered better to suit peculiar needs of the natural enemies. It involves making the environment better suited to the natural enemy and crop adversity may be favorably modified for effectual action of entomophagous insects (Sarwar 2009; 2016b). Holland et al. (2008) demonstrated the empirical impact of natural enemies on pests and the effect of habitat manipulation required if farmers are to be persuaded to adopt conservation biocontrol. Verkerk et al. (1998) identified key ways in which manipulations of the crop environment based on detailed understanding of tritrophic interactions can contribute improvements in the control of insect pests. Such approaches are likely to be of particular benefit against those pests, notably certain species of Lepidoptera and aphid, which are difficult to control with insecticides because of insecticide resistance or suppression of natural enemies by giving particular attention to the compatibility of intercropping and biological control. Conservation biological control involves manipulation of the environment to enhance the survival, fecundity, longevity and behavior of natural enemies to increase their effectiveness (Landis et al. 2000). Such agricultural practices can profoundly affect the population of entomophagous fauna. For pest control, any features of plants, which make it acceptable for predator or unacceptable to the pest, may be considered, because diversification of the flora in an area may be of great help for predatory feeders. Intercropping, an advance agro technique is considered to be effective and potential mean of increasing crop production per unit area, particularly for farmers with small holdings and could be corner stone in integrated pest management (Sarwar 2011). Kalra and Gangwar (1980) reported that this technique is helpful in increasing farm income on sustained basis. Similarly, Ayisi et al. (1997) from their experiment on canola-soybean intercropping concluded that oil seed content increased as compared with sole cropping. Likewise, Verma et al. (1997) reported that intercropping of wheat and mustard gave maximum return. Studies on the environmental conditions are necessary to assess biocontrol agent’s adaptation to the climatic conditions of a locality. McClay (1996) showed that the adaptation of biological control agents to the physical environment can become a major limiting factor to the success of biological control, and failure of biological control agents to establish has sometimes been attributed to lack of adaptation to the climate. Climatic conditions influence insect population dynamics and biocontrol agent establishment, and success has been limited by incompatibility with climates in areas of introduction (Byrne et al. 2002). The present study was therefore; undertaken to determine the feasibility of intercropping pattern in agro ecological conditions from the entomological point of view by underlying the principle for natural enemies’ conservation. These studies initiated accounts for two aims; firstly, to demonstrate relatively positive roles of intercropping association as a guide to study predator’s behavior because insects perceive and react to certain habitat modifications, secondly to demonstrate one of the unconventional approaches to search with respect to pest management. Decision focused towards the planting of maize as intercropping in canola with respect to pest management strategy was due to certain possible reasons; aphid has a common pest status on both crops, lady beetles are frequent aphidophagous predators, and maize can represent a chronic and perennial reservoir of parasitoids species and may be grown throughout the year. Thus, the ultimate objective of this study was to determine how intercropping could affect canola pest populations and their natural enemies under both pure and mixed cropping with maize and their ultimate impacts on crops yield. Materials and methods Study site and agronomic practices Field studies to determine the feasibility of canola-based maize intercropping were carried out at an experimental farm owned by Nuclear Institute of Agriculture, Tandojam, during 2021-2022, and both crops were grown and maintained using standard agronomic techniques. Care was taken to make sure that the outline of methodology adopted and cropping modifications tested should be consonant with the farmer’s socioeconomic circumstances. For experimentation, the main crop canola (variety “Rainbow”) was planted as monocrop and intercropped by using a maize genotype R-2207 on a clay loam soil, in plots each having a net size of 3.5 m 2 and replicated 3 times in randomized complete block design. The experimental treatments were consisted of canola and maize sown alone, 4 rows of canola+ one row of maize and 4 rows of canola+ double rows of maize. Planting of both crops was done in accordance with the standard methods of sowing and these were grown in straight lines. Common agronomic practices were carried out during the entire course of the study and no plant protection measures were adopted. Canola was sown in paired rows with 30 cm distance between the paired rows in monocrop treatment. The line spacing for maize intercropping was also 30 cm inter and intra rows, to produce an appropriate plant density. The field was fertilized by general doses @ 90 kg N and 60 kg P 2 O 5 , all the phosphorous and 1/3 nitrogen was applied at the time of sowing as basal dose, 1/3 N applied with first irrigation and remaining 1/3 N given at flowering stage. First irrigation was applied one month after sowing and subsequent 2 irrigations given at about 3-week intervals. Both the crops were thinned twice, first at 15 cm height and second at 30 cm height to maintain optimum plant population to minimize crop’s competition. Weeds were controlled manually; first weeding was administrated at 15 days after crop emergence and subsequent at 30 days interval. Data on the study site’s temperature and relative humidity were also recorded. Insects sampling and population observation technique Data on different aspects of economical performance and role of intercropping were recorded by using standard procedures throughout the entire growing season. The series of preliminary and final observations determining the outputs of presented cropping system were started from the plants emergence till the crops harvested. For each observation, sampling patches were delimited on the ground and observed simultaneously for pest and predator densities. Observations were also recorded regarding relative activities, behavior, movement, species dominance and population of natural enemies especially coccinellids on both crops. The familiar species were identified in the field and unknown species were taken to laboratory and identified after studying the literature. At fortnightly interval, the aphid and adult coccinellid populations were visually inspected from 15 randomly selected plants (canola and maize treatments separately) per treatment (5 plants per replicate) during the observation period. For each observation, plants to be sampled were located at new positions in the field and information on pest and predator species, and behavior or activity of predators was recorded (observations made on the insect's reactions to field stimuli during day times on each sampling day). Observations were recorded on the number of plants per patch, and numbers of aphid and coccinellids (adults and larvae) present on randomly selected plants. Sampling for observing the attack of maize borer ( Chilo partellus ) (Swindhoe) on maize crop was also conducted from 100 randomly selected plants by counting the numbers of healthy and attacked plants. Particular care was taken to avoid disturbing of the interactions between predators and aphids by reducing observer’s movement, and staying as low as possible within the plant canopy. Grain yield After harvesting and threshing operations of both crops manually, the grain yields in monocrop and intercropped treatments were recorded individually. Statistical analysis Statistical evaluation of the experimental data was carried out by using Analysis of Variance technique (ANOVA), and treatment means were compared using Least Significant Difference (LSD) Test. All data means collected were analyzed using Statistix software (Version 8.1) at 0.5% level. Results The most striking result of current studies was the suppression of aphids’ population by intercropping than monocrop. Double rows of maize with canola plantation harbored significantly the least aphids number than single row planting, because of their capacity to hold maximum lady beetles to predate upon aphids. Data concerning yield parameter reflected that canola planted with two rows of maize appeared to be the more productive practice. Observations on insects’ populations The green peach aphid Myzus persicae (Sulzer) was the most abundant insect pest species (lime-green in colour and noted to be more mobile, 70%) occurring across the study location and season. Other minor aphid species identified were turnip aphid Lipaphis erysimi (Kaltenbach) (dark olive green, 20%) followed by cabbage aphid Brevicoryne brassicae (L.), (grey waxy color, 10%) (DF= 2, F= 372.00, P= 0.0001, SE= 2.357). The results pertaining to the occurrence of natural enemies of aphids reflected that coccinellid lady beetles were the most abundant predators (DF= 2, F= 9.33, P= 0.0311, SE= 7.071) at the experimental site. The most abundant species (Table 1) with respect to their densities were the zigzag beetle Cheilomenes sexmaculata Fabr., (50%), 11-spotted lady beetle Coccinella undecimpunctata L., (30%) and 7-spotted lady beetle Coccinella septempunctata L., (20%). Collectively, these were important biological agents as their adults and immature stages found preying on aphids, therefore, the experiment was mainly focused on these insect predators and detailed observations were made on their activities and movement. The predators occurred relatively coincidently with the appearance of aphid’s population. The peak occurrence of coccinellid species started during peak aphid’s abundance, and as the prey became scarce, the predator was rare. In the same way, migration of the predator to the adjacent crops was delayed at maximum prey density and frequent evacuation observed at lower pest’s densities. However, only the short delay in appearance and dispersal of predator could be due to the time required for their reproduction, oviposition and development differences with aphids prey. The population of adult Cheilomenes species tended to peak in mid December and declined in mid-February, in contrast to the density of Coccinella species, which increased markedly from mid February to the end of March when observations were discontinued on biological control attribute. The main consensus existed from data regarding whether or not to use single crop or intercropping exhibited that maize crop protected the lady beetle from environmental risks and largely favored the predators in early winter to fall. Analysis of the environmental factors on the activities and movement of focal predacious lady beetles had indicated their important role and interesting effects. The predator in its environment was constantly subjected to many stimuli, for example light, temperature and moisture, and response also depended upon interplay of many other physical stimuli received. Insects (lady beetles) were only active during the day for life activities such as searching for food or mates and rested at night within maize whorls. Locomotor activity was affected by the air humidity and temperature. When the air was somewhat hot and dry (before and afternoon), predators tended to increase locomotive activities; however, in cold moist air (morning and evening times) the locomotor activity and speed of movement were decreased, and while making these observations, the insects were not disturbed in their habitat. Light being an important component of the environment, acted as token stimulus guiding the insect to the situations where it could find the optimal requirements for existence. At increased light intensity before noon, the predator became photopositive to have places for survival. Even at clear bright day a temperature of 8.2 to 14.7 o C, formed a temperature ceiling, which arrested active flying until the predator became warm in open atmosphere [temperature ranged from minimum 8.2 0 C (mean 13.75) to maximum 40.0 0 C (mean 30.82) and relative humidity varied from 52.0 to 72.0%) (mean 60.33) during the year 2009-10 (Table 2)]. This insect also tended to avoid fog and dew drops, but was found scattered on the leaves and stalk of maize. Ultimately, the lady beetle was most active during late morning to late afternoon until dusk. The predominant behavior of predators noted during the observations was their resting behavior at intercropped maize planting, which provided shelter and roosting sites for coccinellid beetles. From 1 to 7 adults were found aggregating within central leaves whorl, behind the leaf sheath or slender stalk of same plant; certainly, the maize crop tops were favored roosting sites for predators. When the central whorl of leaves become reasonably large after 4 weeks old, it offered special attraction for adults aggregation which was generally the starting of roosting sites, and from the beginning of December the beetles invaded the maize in maximum number and they were present in diminishing numbers until the end of February when adults feeding was not confined only to the maize. During the beginning of the day, beetles became active, and most of their behavior consisted of movement around and over various parts of plant, presumably to search for an escape. During searching behavior, insects initially moved at random in an undirected manner against the sides of the containing whorls, for a short while against the gravitational pull, and then tracks were followed by the insect where it moved away with greater number of turns. As it approached to the vicinity of the leaf surface, it began to perceive the odor of prey from the leaves. After finding the prey, search pattern changed and it began to feed as prey was available. If prey was not found on maize, it showed rapid movement at random and continued to one or more intensive searching which was reflected by more frequent turns or it moved in a straight path and flown in search of food or mates on canola plant. The degree of movement changed either from simple short flight from one part of the plant to another or extended flight to different canola plants. Near the dusk time, for settlement in maize whorls, roosting site searching behavior of the predator was undirected. It was a sort of common practice to alight on leaves whorl and walking extensively over the site many times for site examining without any reaction. Then the walks were usually interspersed with walking toward the tip of leaves or away from the tip or random wandering to adjacent leaves or toward the stem, looking for suitable site and finally settled in the bottom of central whorl to spend good deal of night time which was in the best interest of insect. The smaller or taller plant heights were equally important for the selection of roosting site, but the interest to maize crop diminished when either winter was over or crop crossed the tasseling stage, accordingly most favoritism was exploited during the period of maximum tassel emergence, so maize was not equally attractive at seedling stage or maturity for predator. The most conspicuous result of this study was the impacts of maize intercropping to suppress the aphid populations by predators. Data on population of aphid per plant (Table 3) had shown highly significant effect of intercropping pattern than monocropping. The maximum number of aphids were noted in treatment of canola (DF= 2, F= 175.09, P= 0.0001, SE= 1.694) and maize (DF= 2, F= 30.59, P= 0.0038, SE= 4.849) planted alone (60.16, 59.86, respectively) which differed statistically from both other treatments. The intercropped canola with double rows of maize showed significantly lower aphid population (28.60 and 22.16 in canola and maize, respectively) as compared to single row planting (41.86 and 37.40 in canola and maize, respectively). Results showed that the double lining of maize (DF= 2, F= 18.47, P= 0.0095, SE= 0.448) and canola (DF= 2, F= 2489.25, P= 0.0000, SE= 0.0094) intercropping gave better results than single lining of maize and canola, and control treatments for holding higher predator populations (3.00, 2.16 and 1.33 beetles per maize plant) and (0.79, 0.66 and 0.16 per canola plant), respectively. Sampling data for maize borer’s infestation on maize crop, showed only 3% damage symptoms in intercultured crop (double lines) compared to single line (6%). Whereas, observations showed 9% stalks damage by maize borer recorded on monocropping grown maize (DF= 2, F= 81.00, P= 0.0006, SE= 0.471). Grain yield Data concerning crop yields (Table 4), reflected that intercropping pattern had significant effects on this parameter. Minimum yield was obtained in canola (484.40 gm/ 3.5 m 2 ) (1384. 00 kg/ hec) and maize (836.70 gm/ 3.5 m 2 ) (2390.57 kg/ hec) planted alone which differed significantly from rest of treatments (DF= 2, F= 18.29, P= 0.0097, SE= 31.941). Canola planted with double row of maize intercropping appeared to be the most productive practice obtaining (675.20 gm/ 3.5 m 2 ) (1929.14 kg/ hec) & (1089.00 gm/ 3.5 m 2 ) (3111.42 kg/ hec) yield, and remained more profitable than single row plating (553.50 gm/ 3.5 m 2 ) (1581.42 kg/ hec) & (880.80 gm/ 3.5 m 2 ) (2516.57 kg/ hec), respectively (DF= 2, F= 130.29, P= 0.0002, SE= 16.742). Discussion During present experimentation, the goal achieved was the significance of maize crop as a reservoir of beetle predators from environmentally adverse factors. This attraction to predatory insect may be olfactory or visual; however, additional plant characteristics such as surface chemicals may present additional cues that stimulated predator’s attraction. These findings are supported by the observations of Grevstad and Klepetka (1992) who reported about the movement of adult conccinellids on crucifers and suggested that movement along leaf edges and stems was more efficient and the risk of falling from the plant remained very rare. Obata (1997), and Griffin and Yeargan (2002) suggested that lady beetles Harmonia and Coleomegilla (Coccinellid) used olfactory and visual cues to detect their prey. The manipulations of such predator’s reservoirs had been emphasized since longtime, for instance, Forbes (1883) noted coccinellid species feed on maize pollens. Bosch and Telford (1970) suggested that cultivation of corn served as host to many insect species, which were ideal for the reproduction of entomophagous insects. Stary (1987) was also of the same opinion for the establishment of parasitoid reservoirs. So, the intercrop plantation can affect predaceous arthropods abundance and behavior to enhance the number of predators, otherwise, their exposure to cold and short day length could hasten dormancy or enhance dispersal, but the presence of maize retarded such environmental constraints. The lower number of aphids on double row planting could be because of maize’s capacity to hold maximum coccinellid predators and their more severe competition for feeding on aphid prey, as compared to single row planting. These results are somewhat in agreement with Gliessmann (1987), who for aphid control in brassica crops exploited the crop-weed associations like Chenopodium album Linnaeus . Amjad et al. (1987) suggested that mass-reared individuals of C. septempuctata should be released when crop is at flowering, as this stage was most susceptible to damage by aphids. Kyamanywa and Tukahirwa (1988), and Ekesi et al. (1999) conducted field experiments to assess the combined effects of intercropping cowpea with maize inoculated with fungus. Results suggested that pest density and damage were significantly lower in intercrop than in the monocrop. Stary and Gonzalyez (1991) evaluated positive roles of C. album occurring both on farm land and urban environments in presenting reservoirs of useful parasitoids for aphid control. Bianchi et al. (2007) analyzed whether changes in crop selection could explain the dramatic and unexplained decline in abundance of the ladybeetle C. septempunctata . The results indicated that the population viability of C. septempunctata was highly dependent on availability of aphid prey in crops, in particular cereal, which served as their major reproduction habitat. The current results revealed that maximum yield was recorded for canola and double maize lining, which can mainly be attributed to their holding the maximum number of predators to suppress the aphid. Atwal (1976) pointed out that owing to the very high population of aphid, the developing pods did not produce healthy seeds and yield of infested crop was reduced to one fourth or one fifth. Additionally, thigh yield was due to less competition among crop plants for nutrients, moisture, light and space for survival, and both the crop plants fully utilized available resources. Further, plant quality traits and flower attributes were typical in intercrops. A parallel statement was made by Cresswell et al. (2001) that none of the attributes of individual B. napus flower (petal length, petal width, stamen length, pistil length, pollen production, diameter of pollen grains and nectar production) varied with plant density. In the face of resource scarcity, the plants apparently conserved flower size. Sampling for maize borer attack on maize crop showed that infestation was lower on intercultured than monocropping. These observations are supported by the findings of Jotwani and Verma (1969) who reported that aphidophagus coccinallids also feed on non-aphid hosts including sorghum stem borer. Similarly, Andow (1990) found coccinellid species feeding on lepidopterous eggs and larvae. In field experiments, studies conducted by Kurmvanshi et al. (1994) on intercropping of oilseeds and pulses with wheat concluded that wheat grown between maize and soyabean strips improved soyabean production over the two-crop systems without adversely affecting wheat yields. Moreover, Du et al. (2004) investigated that allelochemical contents should be taken into account in integrated pest management for their effects on both herbivores and entomophagous insects. Wang et al. (2009) evaluated the effects of intercropping of wheat cultivars and oilseed rape on the densities of wheat aphid, Sitobion avenae (Fabricius), and their arthropod natural enemies. The results showed that the densities of S. avenae were significantly higher on the monoculture pattern than on either the 8-2 intercropping pattern (eight rows of wheat with two rows of oilseed rape) or the 8-4 intercropping pattern (eight rows of wheat with four rows of oilseed rape). The mean number of predators (ladybeetles) and the parasitization rates of S. avenae were significantly higher in two intercropping patterns than those in the monoculture pattern. The results showed that wheat-oilseed rape intercropping conserved more predators and parasitoids than in wheat monoculture fields. Li et al. (1994) studied the relationships among wheat aphids, their natural enemies and wheat yield loss. Yield losses were significantly correlated with the population densities of pests S. avenae and Rhopalosiphum padi Linnaeus and predator C. septempunctata . However, the results of Ali et al. (2000) revealed that canola grown with one row of wheat produced the highest canola seed yield. Intercropping was found to reduce aphid’s density compared with monoculture. Furthermore, natural enemies, in this case mainly predators, significantly reduced the numbers of aphids, showing that it is possible to retain the predation pressure in intercropped systems. Hence, the intercrop disrupts herbivorous insect pest, reduces insect damage as the insects are more abundant on an alternative host, and diverse habitats attract and retain more enemies of insect pests compared with a monoculture. Thus, adding more plant species to a system affect herbivores in two major ways; firstly, the environment of the host plants (e.g., neighboring plants and microclimatic conditions), are altered, and secondly, host plant quality (e.g., morphology and chemical content), are changed (Langer et al. 2007). Changes in environment and host plant quality lead to direct effects on the host plant searching behavior of herbivorous insects, as well as indirect effects on their developmental rates and on interactions with natural enemies (Bukowinsky et al. 2004). The mechanism behind the direct effects of intercropping states that when an herbivorous insect lands on an intercrop plant instead of a host plant, its behavioral sequence is disrupted (Finch and Collier 2000). The control crops, often a pure stand of host plants, then function as a trap crop, suffering higher herbivore densities and damage (Bommarco and Banks 2003). The indirect consequences of intercropping include effects on the natural enemy’s community. The effect of natural enemies is enhanced in mixed cropping systems, because these systems provide a variety of microhabitats and alternative prey (Root 1973). Besides an alteration in the host plant environment of intercropping systems directly affecting herbivore behavior, crop plants in intercropping systems often compete with the intercrop for resources such as light, water and nutrients. These factors may have consequences for plant growth (Ramert 1996), morphology (Hooks and Johnson 2001), and chemical composition (Osier and Jennings 2007), which in turn could affect host plant finding and acceptance by herbivores (Den Belder et al. 2000). Indirectly, this might also change the suitability of the crop plant as a food source for insect herbivores (Simpson and Raubenheimer 1995), which could have consequences for their development rates (Bukowinsky et al. 2004; Osier and Jennings 2007). Among plant quality traits found to affect herbivore development are their fiber and nutrient contents (Hochuli, 1993), which can both be affected by environmental conditions (Osier and Jennings 2007), and might therefore be expected to vary between monocultured and intercropped plants. On the other hand, the resource competition may limit the ability of a plant to defend itself from natural enemies, leading to greater herbivory on B. napus plants (Cipollini and Bergelson 2002). The overall results of current research work showed that abiotic factors like relative humidity and temperature also contribute on the population fluctuation of insects. Li et al. (1994) found that numbers of natural enemies were correlated with certain abiotic factors such as mean temperature, relative humidity and rainfall. Lactin et al. (1995) studied that in general, the relationship between insect development rate and temperature was curvilinear, this information may be used to estimate whether that location will provide sufficient physiological time for a particular insect species to complete its development and to lay a full complement of eggs. Thus, in this cropping system, natural enemies as well as abiotic factors played a greater role in shaping the population dynamics of insects. These results can be used to guide the selection of biocontrol agents for release and the selection of release sites may be successful in pest control. The use of climatic conditions to predict possible areas of establishment has several benefits in pest control programs. Suitable climatic conditions can avoid the waste of effort involved in continuing the attempts to establish an agent which is not adapted to local climatic conditions; suggest a change in release strategy for an agent which did not establish from initial releases; and provide encouragement to continue with releases of an agent (Sarwar and Saqib 2010; Sarwar 2016c; Sarwar and Roohi, 2020). Since, this study has been initiated to use in pest management strategy, the predator preferred host plants like maize could be grown as intercrop, it can either be harvested for fodder, or otherwise be kept as grain crop. Alternatively, border plantation of maize around rape and mustard fields is recommended to enhance aphid’s predation by coccinellids. Conclusion In reducing the need for chemicals, current research efforts initiated achieved the goal of natural enemy’s conservation by focusing on the role of intercropping through planting of more than one crop in close proximity as part of the same farming system. Demonstrated advantages of intercropped maize plants displayed a reduction in aphid’s and maize borer’s populations enlightened by attracting higher numbers of lady beetle predators for organic farming. Additionally, the compatibility of intercropping with pest management strategy can reduce the disruption of natural enemies along with promoting biodiversity and sustaining environmental quality. It is emphasized that canola-maize intercropping can successfully be practiced without any intercrop competition. Such intercropping can also modify the microclimate of crop fields making them more favorable for parasitoids. For pest control, all the considerations including any attractive feature of plant that is acceptable for entomophagous insects must be weighed while deciding the cropping system. It is predicted that such natural enemies’ conservation practices in some form could be a part of innovative integrated pest management strategies in holistic framework and consonant with farmer’s socioeconomic circumstances. Nevertheless, reduced pest intensities and increased grain yield obtained from the intercrops, could offer multiple benefits and adoption of this important tool would have very positive implications for the farmers in sustainable agriculture. Declarations Funding This research received no external funding. Acknowledgments The author acknowledges the staff members for sampling and data collection. Data availability All data of the study have been presented in the manuscript. Declarations Conflicts of Interest: No potential conflict of interest is reported by the author of this article. 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Omkar, Pervez A, Mishra G, Srivastava S, Singh SK, Gupta A (2005) Intrinsic advantages of Cheilomenes sexmaculata over two coexisting Coccinella species (Coleoptera: Coccinellidae). Insect Science 12 (3): 179-184. Osier TL, Jennings SM (2007) Variability in host-plant quality for the larvae of a polyphagous insect folivore in midseason: The impact of light on three deciduous sapling species. Entomol Exp Appl 123: 159-166. Ramert B (1996) Intercropping as a strategy for reducing damage to carrots caused by the carrot fly, Psila rosae . Biol Agric Hortic 13: 359-369. Root R (1973) Organisation of a plant-arthropod association in simple and diverse habitats. The fauna of collards ( Brassica oleracea ). Ecological Monographs 43: 95-124. Sarwar, M (2009) Populations’ synchronization of aphids (Homoptera: Aphididae) and ladybird beetles (Coleoptera: Coccinellidae) and exploitation of food attractants for predator. Biological Diversity and Conservation 2 (2): 85-89. Sarwar M, Saqib SM (2010) Rearing of Predatory Seven Spotted Ladybird Beetle Coccinella septempunctata L. (Coccinellidae) on Natural and Artificial Diets under Laboratory Conditions. Pak J Zool 42 (1): 47-51. Sarwar M (2011) Effects of wheat and barley intercropping ecosystem on the prevalence of aphid (Hemiptera: Aphididae) population in canola ( Brassica napus L.) crop. Biological Diversity and Conservation 4 (1): 11-16. Sarwar M, Ahmad N, Tofique M (2011) Impact of Soil Potassium on Population Buildup of Aphid (Homoptera: Aphididae) and Crop Yield in Canola ( Brassica napus L.) Field. Pak J Zool 43 (1): 15-19. Sarwar M (2016a) Biological Control to Maintain Natural Densities of Insects and Mites by Field Releases of Lady Beetles (Coleoptera: Coccinellidae). International Journal of Entomology and Nematology 2 (1): 21-26. Sarwar M (2016b) Food habits or preferences and protecting or encouraging of native ladybugs (Coleoptera: Coccinellidae). International Journal of Zoology Studies 1 (3): 13-18. Sarwar M (2016c) Recognition of some lady beetles (Coleoptera: Coccinellidae) deadly sighted for insect and mite pests in agroecosystems. Int. J. Entomol. Res 1 (2): 29-34. Sarwar, M (2017) Integrated Control of Insect Pests on Canola and Other Brassica Oilseed Crops in Pakistan. In: Integrated Management of Insect Pests on Canola and Other Brassica Oilseed Crops, Gadi, V.P. Reddy (Ed.). CABI, Oxfordshire, UK. p. 193-221. Sarwar, M. and Roohi, A (2020) New advances in insect vector biology and virus epidemiology. In: Applied Plant Virology: Advances, Detection, and Antiviral Strategies, L. P. Awasthi (Ed.). Elsevier Inc., London. p. 301-311. Simpson SJ, Raubenheimer D (1995) The geometric analysis of feeding and nutrition: A user’s guide. J Insect Physiol 7: 545-553. Solbreck C (1974) Maturation of pest hibernation flight behaviour in the coccinellid Coleomegilla maculate (Degree). Oecologia 17: 265-275. Stary P, Gonzalyez D (1991) The Chenopodium aphid, Hayhurstia atriplicis (L.) agents in pest management. J Appl Entomol 111: 243-246. Stary P (1987) Aphid parasitoids in an urban environment (Hymenoptera, Aphididae). Acta Entomol Bohemoslov. 84: 91-101. Steel RGD, Torrie JH. (1980 Principles and Procedures of Statistic. A biometric approach. Mc-Graw Hill Book Co. Inc. New York. p. 633. Verkerk RHJ, Leather SR, Wright DJ (1998) The potential for manipulating crop-pest-natural enemy interactions for improved insect pest management. Bull Entomol Res 88: 493-501. Verma UN, Pal SK, Singh MK, Thakur R (1997) Productivity, Energetics and competition function of wheat ( Triticum aestivum L.) plus, Indian mustard ( Brassica juncea L.) intercropping under varying fertilizer level. Ind J Agron 42: 201-204. Wang W, Liu Y, Chen J, Ji X, Zhou H, Wang G ( 2009 ) Impact of intercropping aphid-resistant wheat cultivars with oilseed rape on wheat aphid ( Sitobion avenae ) and its natural enemies. Acta Ecol. Sin 29 (3): 186-191. Weber G (1985) Genetic variability in host plant adaptation of the green peach aphid, Myzus persicae. Entomol Exp Appl 38 (1): 49-56. Wright EJ, laing JE (1982) Stage specific mortality of Coleomegilla maculate lengi Timberlake on corn in southern Ontario. Environ Entomol 11: 32-37. Tables Table 1 Percent species composition of coccinellid lady beetles and aphids in experimental field on canola and maize Insect Name of species Percent composition Predator Zigzag beetle Cheilomenes sexmaculata 50 a 11-Spotted lady beetle Coccinella undecimpunctata 30 b 7-Spotted lady beetle Coccinella septempunctata 20 b Standard Error 7.071 Pest Green peach aphid Myzus persicae 70.00 a Turnip aphid Lipaphis erysimi 20.00 b Cabbage aphid Brevicoryne brassicae 10.00 c Standard Error 2.357 Different alphabetical letters in column denote statistical significance values at alpha 0.05. Table 2 Meteorological data during the year 2021-2022 at experimental field Year/ Temperature ( 0 C) R. H. % Month 2021-2022 Minimum ( 0 C) Maximum ( 0 C) November 14.7 31.0 59.0 December 10.8 26.2 72.0 January 8.2 25.3 68.0 February 10.0 27.5 58.0 March 16.8 34.9 52.0 April 22.0 40.0 53.0 Mean 13.75 30.82 60.33 Table 3 Mean numbers of aphids and adult ladybird beetles on canola and maize crops Treatments Canola Maize Aphid number/ plant Predator (Lady beetle) number/ plant Aphid number/ Plant Predator (Lady beetle) number/ plant Maize borer infestation (%) T 1 = Canola/ Maize alone (Control) 60.16 a 0.16 c 59.86 a 1.33 c 9.00 a T 2 = Canola + single line of maize 41.86 b 0.66 b 37.40 b 2.16 b 6.00 b T 3 = Canola + double line of maize 28.60 c 0.79 a 22.16 c 3.00 a 3.00 c Standard Error 1.694 0.0094 4.849 0.448 0.471 Different alphabetical letters in same column denote statistical significance values at alpha 0.05. Table 4 Mean seed yield of canola and maize crops at experimental field Treatments Canola Maize Yield / plot (3.5 m 2 ) (gm) Yield/ Hectare (Kg) Yield/ plot (3.5 m 2 ) (gm) Yield/ Hectare (Kg) T 1 = Canola/ Maize alone (Control) 484.40 c 1384. 00 836.70 c 2390.57 T 2 = Canola + single line of maize 553.50 b 1581.42 880.80 b 2516.57 T 3 = Canola + double line of maize 675.20 a 1929.14 1089.00 a 3111.42 Standard Error 31.941 16.742 Different alphabetical letters in same column denote statistical significance values at alpha 0.05. 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They\u0026nbsp;posture a momentous menace to worldwide crops production\u0026nbsp;and are also major vectors of certain plant viruses (Ng\u0026nbsp;and\u0026nbsp;Perry 2004).\u0026nbsp;Plants have established protecting compounds known as phenolics, alkaloids, terpenoids, a well as sulfur and nitrogen containing metabolites, which display favorable features against aphids, such as aphicidal and antifeedant, thus disturbing persistence fitness. Plants react to aphid invasion by activating defense genes that lead to the creation of physical hurdles and lethal chemicals (direct resistance). Additionally, attacked plants can appeal to natural enemies of aphids by liberating particular volatile compounds (indirect resistance)\u0026nbsp;(Farhan\u0026nbsp;et al. 2024).\u0026nbsp;The green peach aphid, \u003cem\u003eMyzus persicae\u003c/em\u003e (Sulzer), is a polyphagous pest on over 400 plant species in more than 50 families. Phenotypic plasticity of individuals and genetic variability in the population presumably contribute to this polyphagy (Weber 1985). Liyun and \u0026nbsp;Gexia (2006) reported 70 species of aphids and their host plants include 58 genera. The importance of oilseed rape (\u003cem\u003eBrassica napus\u003c/em\u003e Linnaeus) as a source of industrial and nutritional oil has been increasing worldwide. In many regions, the increase in its acreage was accompanied by a dramatic and disproportionate increase of pesticide uses because oilseed rape is attacked by a range of pest species (Alford et al. 2003).\u0026nbsp;Mussury\u0026nbsp;and Fernandes (2002), observed aphids\u0026rsquo; population from initial stage of canola [rape] plant development to senescence. Aphids were more abundant during the flowering phase, and they usually located in the stems of the inflorescence and developing fruits. The yield of this crop however, can be substantially increased to a greater extent by adopting suitable plant protection measures. Undoubtedly, due to harmful effects of toxic pesticides and intensive trend for research into biological control, today there is a critical need for alternatives to chemical control.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe ladybird beetles belong to the family Coccinellidae of order Coleoptera and the members of this family are exclusively predators on small soft bodied insect pests (Omkar and Pervez 2000).\u0026nbsp;The\u0026nbsp;\u003cem\u003eCheilomenes sexmaculata\u003c/em\u003e (Fabricius), an aphidophagus coccinellid, feeds on pests, but also feeds upon non-aphid hosts.\u0026nbsp;High values of life history parameters, viz., developmental rate, immature survival, fecundity, egg viability, reproductive rate, conversion efficiency of ingested food, fecundity after single mating and intrinsic advantages of \u003cem\u003eC. sexmaculata\u003c/em\u003e over the \u003cem\u003eCoccinella\u003c/em\u003e species have been studied\u0026nbsp;(Omkar\u0026nbsp;et al.\u0026nbsp;2005). The lady beetle \u003cem\u003eCoccinella septempunctata\u003c/em\u003e Linnaeus, is an important predator of aphids in arable crops (Bianchi\u0026nbsp;and\u0026nbsp;Werf 2003). \u003cstrong\u003eCabral\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eet al.\u0026nbsp;(2009) showed\u003cem\u003e\u0026nbsp;Coccinella undecimpunctata\u003c/em\u003e Linnaeus,\u0026nbsp;to be an effective predator for the biological control of \u003cem\u003eM. persicae\u003c/em\u003e, and the presence of both 4\u003csup\u003eth\u003c/sup\u003e instar larvae and adults of this ladybird beetle could increase the efficiency in field pest suppression. These predators predate upon many species of aphids, mites, scale insects, aleyrodids, mealy bugs and citrus pryllid (Nayar and Krishnan 1989). Unfortunately, these coccinellids meet resistances from a number of environmental variations, for instance, as days get shorter and temperatures fall, ladybird beetles seek shelter behind bark, under leaves or in other protected locations, and such requirements of the adults may limit their potential as biocontrol agents in field\u0026nbsp;(Sarwar 2016a). Hagen (1962) pointed out the phenomenon of hibernation in many coccinellids; while, Solbreck (1974) examined the coccinellid adults hibernating in large aggregations in grass and dead leaves accumulated at the bases of large trees. This microhabitat provided insulation against fluctuating temperature, but despite of those adaptations, mortality at hibernation sites was high. Wright and Laing (1982) found differing mortality rates between 6.8%\u0026nbsp;and\u0026nbsp;57% in coccinellids. Felland and Hull (1996) determined the spatial and temporal distribution of lady beetles in all available ground cover habitats and surrounding refuges. Density of over wintering adults was noted at peak in the autumn and declined in the spring. Studies on influences of these factors on the activity of these predators can be helpful in understanding the ways in which such insects could survive in their natural habitats. As a result, devising approaches and strategies for the utilization and conservation of natural enemies as biocontrol agents sparked my interest in studying conservation of predaceous lady beetles.\u003c/p\u003e\n\u003cp\u003eFor the enhancement of biological control, the encouragement of the natural enemy has always been an attractive idea to the entomologists. The important approach would be to modify the environment in such as way that any adverse environmental effects could be altered better to suit peculiar needs of the natural enemies. It involves making the environment better suited to the natural enemy and crop adversity may be favorably modified for effectual action of entomophagous insects\u0026nbsp;(Sarwar 2009; 2016b). Holland et al. (2008) demonstrated the empirical impact of natural enemies on pests and the effect of habitat manipulation required if farmers are to be persuaded to adopt conservation biocontrol. Verkerk et al. (1998) identified key ways in which manipulations of the crop environment based on detailed understanding of tritrophic interactions can contribute improvements in the control of insect pests. Such approaches are likely to be of particular benefit against those pests, notably certain species of Lepidoptera and aphid, which are difficult to control with insecticides because of insecticide resistance or suppression of natural enemies by giving particular attention to the compatibility of intercropping and biological control.\u003c/p\u003e\n\u003cp\u003eConservation biological control involves manipulation of the environment to enhance the survival, fecundity, longevity and behavior of natural enemies to increase their effectiveness (Landis et al. 2000). Such agricultural practices can profoundly affect the population of entomophagous fauna. For pest control, any features of plants, which make it acceptable for predator or unacceptable to the pest, may be considered, because diversification of the flora in an area may be of great help for predatory feeders. Intercropping, an advance agro technique is considered to be effective and potential mean of increasing crop production per unit area, particularly for farmers with small holdings and could be corner stone in integrated pest management (Sarwar 2011). Kalra\u0026nbsp;and\u0026nbsp;Gangwar (1980) reported that this technique is helpful in increasing farm income on sustained basis. Similarly, Ayisi et al. (1997) from their experiment on canola-soybean intercropping concluded that oil seed content increased as compared with sole cropping. Likewise, Verma et al. (1997) reported that intercropping of wheat and mustard gave maximum return.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eStudies on the environmental conditions are necessary to assess biocontrol agent\u0026rsquo;s adaptation to the climatic conditions of a locality. McClay (1996) showed that the adaptation of biological control agents to the physical environment can become a major limiting factor to the success of biological control, and failure of biological control agents to establish has sometimes been attributed to lack of adaptation to the climate. Climatic conditions influence insect population dynamics and biocontrol agent establishment, and success has been limited by incompatibility with climates in areas of introduction (Byrne et al. 2002). The present study was therefore; undertaken to determine the feasibility of intercropping pattern in agro ecological conditions from the entomological point of view by underlying the principle for natural enemies\u0026rsquo; conservation. These studies initiated accounts for two aims; firstly, to demonstrate relatively positive roles of intercropping association as a guide to study predator\u0026rsquo;s behavior because insects perceive and react to certain habitat modifications, secondly to demonstrate one of the unconventional approaches to search with respect to pest management. Decision focused towards the planting of maize as intercropping in canola with respect to pest management strategy was due to certain possible reasons; aphid has a common pest status on both crops, lady beetles are frequent aphidophagous predators, and maize can represent a chronic and perennial reservoir of parasitoids species and may be grown throughout the year. Thus, the ultimate objective of this study was to determine how intercropping could affect canola pest populations and their natural enemies under both pure and mixed cropping with maize and their ultimate impacts on crops yield.\u003c/p\u003e"},{"header":"Materials and methods","content":"\u003cp\u003e\u003cstrong\u003eStudy site and agronomic practices\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eField studies to determine the feasibility of canola-based maize intercropping were carried out at an experimental farm owned by Nuclear Institute of Agriculture, Tandojam, during 2021-2022,\u0026nbsp;and both crops were grown and maintained using standard agronomic techniques.\u0026nbsp;Care was taken to make sure that the outline of methodology adopted and cropping modifications tested should be consonant with the farmer\u0026rsquo;s socioeconomic circumstances. For experimentation, the main crop canola (variety \u0026ldquo;Rainbow\u0026rdquo;) was planted as monocrop and intercropped by using a maize genotype R-2207 on a clay loam soil, in plots each having a net size of 3.5 m\u003csup\u003e2\u003c/sup\u003e and replicated 3 times in randomized complete block design. The experimental treatments were consisted of canola and maize sown alone, 4 rows of canola+ one row of maize and 4 rows of canola+ double rows of maize. Planting of both crops was done in accordance with the standard methods of sowing and these were grown in straight lines. Common agronomic practices were carried out during the entire course of the study and no plant protection measures were adopted. Canola was sown in paired rows with 30 cm distance between the paired rows in monocrop treatment. The line spacing for maize intercropping was also 30 cm inter and intra rows, to produce an appropriate plant density. The field was fertilized by general doses @ 90 kg N and 60 kg P\u003csub\u003e2\u003c/sub\u003e O\u003csub\u003e5\u003c/sub\u003e, all the phosphorous and 1/3 nitrogen was applied at the time of sowing as basal dose, 1/3 N applied with first irrigation and remaining 1/3 N given at flowering stage. First irrigation was applied one month after sowing and subsequent 2 irrigations given at about 3-week intervals. Both the crops were thinned twice, first at 15 cm height and second at 30 cm height to maintain optimum plant population to minimize crop\u0026rsquo;s competition. Weeds were controlled manually; first weeding was administrated at 15 days after crop emergence and subsequent at 30 days interval. Data on the study site\u0026rsquo;s temperature and relative humidity were also recorded.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eInsects sampling and population observation technique\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData on different aspects of economical performance and role of intercropping were recorded by using standard procedures throughout the entire growing season. The series of preliminary and final observations determining the outputs of presented cropping system were started from the plants emergence till the crops harvested. For\u0026nbsp;each observation, sampling patches were delimited on the ground and observed simultaneously for pest and predator densities.\u0026nbsp;Observations were also recorded regarding relative activities, behavior, movement, species dominance and population of natural enemies especially coccinellids on both crops. The familiar species were identified in the field and unknown species were taken to laboratory and identified after studying the literature. At fortnightly interval, the aphid and adult coccinellid populations were visually inspected from 15 randomly selected plants (canola and maize treatments separately) per treatment (5 plants per replicate)\u0026nbsp;during the observation period.\u0026nbsp;For each observation, plants to be sampled were located at new positions in the field and information on pest and predator species, and behavior or activity of predators was recorded (observations made on the insect\u0026apos;s reactions to field stimuli\u0026nbsp;during day times on each sampling day). Observations were recorded on the number of plants per patch, and numbers of aphid and coccinellids (adults and larvae) present on randomly selected plants.\u0026nbsp;Sampling for observing the attack of maize borer (\u003cem\u003eChilo partellus\u003c/em\u003e) (Swindhoe) on maize crop was also conducted from 100 randomly selected plants by counting the numbers of healthy and attacked plants. Particular care was taken to avoid disturbing of the interactions between predators and aphids by reducing observer\u0026rsquo;s movement, and staying as low as possible within the plant canopy.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eGrain yield\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAfter harvesting and threshing operations of both crops manually, the grain yields in monocrop and intercropped treatments were recorded individually.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eStatistical analysis\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eStatistical evaluation of the experimental data was carried out by using Analysis of Variance technique (ANOVA), and treatment means were compared using Least Significant Difference (LSD) Test. All data means collected were analyzed using Statistix software (Version 8.1) at 0.5% level.\u003c/p\u003e"},{"header":"Results","content":"\u003cp\u003eThe most striking result of current studies was the suppression of aphids\u0026rsquo; population by intercropping than monocrop. Double rows of maize with canola plantation harbored significantly the least aphids number than single row planting, because of their capacity to hold maximum lady beetles to predate upon aphids. Data concerning yield parameter reflected that canola planted with two rows of maize appeared to be the more productive practice.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eObservations on insects\u0026rsquo; populations\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe green peach aphid \u003cem\u003eMyzus persicae\u003c/em\u003e (Sulzer) was the most abundant insect pest species (lime-green in colour and noted to be more mobile, 70%) occurring across the study location and season. Other minor aphid species identified were turnip aphid \u003cem\u003eLipaphis erysimi\u0026nbsp;\u003c/em\u003e(Kaltenbach)\u0026nbsp;(dark olive green, 20%) followed by cabbage aphid \u003cem\u003eBrevicoryne brassicae\u003c/em\u003e (L.),\u0026nbsp;(grey waxy color, 10%)\u0026nbsp;(DF= 2, F= 372.00, P= 0.0001, SE=\u0026nbsp;2.357).\u0026nbsp;The results pertaining to the occurrence of natural enemies of aphids reflected that coccinellid lady beetles were the most abundant predators (DF= 2, F=\u0026nbsp;9.33, P=\u0026nbsp;0.0311, SE=\u0026nbsp;7.071) at the experimental site. The most abundant species (Table 1) with respect to their densities were the zigzag beetle \u003cem\u003eCheilomenes sexmaculata\u003c/em\u003e Fabr., (50%), 11-spotted lady beetle \u003cem\u003eCoccinella undecimpunctata\u003c/em\u003e L., (30%) and 7-spotted lady beetle \u003cem\u003eCoccinella septempunctata\u003c/em\u003e L., (20%). Collectively, these were important biological agents as their adults and immature stages found preying on aphids, therefore, the experiment was mainly focused on these insect predators and detailed observations were made on their activities and movement. The predators occurred relatively coincidently with the appearance of aphid\u0026rsquo;s population. The peak occurrence of coccinellid species started during peak aphid\u0026rsquo;s abundance, and as the prey became scarce, the predator was rare. In the same way, migration of the predator to the adjacent crops was delayed at maximum prey density and frequent evacuation observed at lower pest\u0026rsquo;s densities. However, only the short delay in appearance and dispersal of predator could be due to the time required for their reproduction, oviposition and development differences with aphids prey. The population of adult \u003cem\u003eCheilomenes\u003c/em\u003e species tended to peak in mid December and declined in mid-February, in contrast to the density of\u003cem\u003e\u0026nbsp;Coccinella\u003c/em\u003e species, which increased markedly from mid February to the end of March when observations were discontinued on biological control attribute. The main consensus existed from data regarding whether or not to use single crop or intercropping exhibited that maize crop protected the lady beetle from environmental risks and largely favored the predators in early winter to fall.\u003c/p\u003e\n\u003cp\u003eAnalysis of the environmental factors on the activities and movement of focal predacious lady beetles had indicated their important role and interesting effects. The predator in its environment was constantly subjected to many stimuli, for example light, temperature and moisture, and response also depended upon interplay of many other physical stimuli received. Insects (lady beetles) were only active during the day for life activities such as searching for food or mates and rested at night within maize whorls. Locomotor activity was affected by the air humidity and temperature. When the air was somewhat hot and dry (before and afternoon), predators tended to increase locomotive activities; however, in cold moist air (morning and evening times) the locomotor activity and speed of movement were decreased, and while making these observations, the insects were not disturbed in their habitat. Light being an important component of the environment, acted as token stimulus guiding the insect to the situations where it could find the optimal requirements for existence. At increased light intensity before noon, the predator became photopositive to have places for survival. Even at clear bright day a temperature of 8.2 to 14.7 \u003csup\u003eo\u003c/sup\u003eC, formed a temperature ceiling, which arrested active flying until the predator became warm in open atmosphere [temperature ranged from minimum 8.2\u003csup\u003e0\u003c/sup\u003eC (mean 13.75) to maximum 40.0\u003csup\u003e0\u003c/sup\u003eC (mean 30.82) and relative humidity varied from 52.0 to 72.0%) (mean 60.33) during the year 2009-10 (Table 2)]. This insect also tended to avoid fog and dew drops, but was found scattered on the leaves and stalk of maize. Ultimately, the lady beetle was most active during late morning to late afternoon until dusk.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe predominant behavior of predators noted during the observations was their resting behavior at intercropped maize planting, which provided shelter and roosting sites for coccinellid beetles. From 1 to 7 adults were found aggregating within central leaves whorl, behind the leaf sheath or slender stalk of same plant; certainly, the maize crop tops were favored roosting sites for predators. When the central whorl of leaves become reasonably large after 4 weeks old, it offered special attraction for adults aggregation which was generally the starting of roosting sites, and from the beginning of December the beetles invaded the maize in maximum number and they were present in diminishing numbers until the end of February when adults feeding was not confined only to the maize. During the beginning of the day, beetles became active, and most of their behavior consisted of movement around and over various parts of plant, presumably to search for an escape. During searching behavior, insects initially moved at random in an undirected manner against the sides of the containing whorls, for a short while against the gravitational pull, and then tracks were followed by the insect where it moved away with greater number of turns. As it approached to the vicinity of the leaf surface, it began to perceive the odor of prey from the leaves. After finding the prey, search pattern changed and it began to feed as prey was available. If prey was not found on maize, it showed rapid movement at random and continued to one or more intensive searching which was reflected by more frequent turns or it moved in a straight path and flown in search of food or mates on canola plant. The degree of movement changed either from simple short flight from one part of the plant to another or extended flight to different canola plants. Near the dusk time, for settlement in maize whorls, roosting site searching behavior of the predator was undirected. It was a sort of common practice to alight on leaves whorl and walking extensively over the site many times for site examining without any reaction. Then the walks were usually interspersed with walking toward the tip of leaves or away from the tip or random wandering to adjacent leaves or toward the stem, looking for suitable site and finally settled in the bottom of central whorl to spend good deal of night time which was in the best interest of insect. The smaller or taller plant heights were equally important for the selection of roosting site, but the interest to maize crop diminished when either winter was over or crop crossed the tasseling stage, accordingly most favoritism was exploited during the period of maximum tassel emergence, so maize was not equally attractive at seedling stage or maturity for predator.\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe most conspicuous result of this study was the impacts of maize intercropping to suppress the aphid populations by predators. Data on population of aphid per plant (Table 3) had shown highly significant effect of intercropping pattern than monocropping. The maximum number of aphids were noted in treatment of canola (DF= 2, F= 175.09, P= 0.0001, SE= 1.694) and maize (DF= 2, F= 30.59, P= 0.0038, SE= 4.849) planted alone (60.16, 59.86, respectively) which differed statistically from both other treatments. The intercropped canola with double rows of maize showed significantly lower aphid population (28.60 and 22.16 in canola and maize, respectively) as compared to single row planting (41.86 and 37.40 in canola and maize, respectively). Results showed that the double lining of maize (DF= 2, F= 18.47, P= 0.0095, SE= 0.448) and canola (DF= 2, F= 2489.25, P= 0.0000, SE= 0.0094) intercropping gave better results than single lining of maize and canola, and control treatments for holding higher predator populations (3.00, 2.16 and 1.33 beetles per maize plant) and (0.79, 0.66 and 0.16 per canola plant), respectively. Sampling data for maize borer\u0026rsquo;s infestation on maize crop, showed only 3% damage symptoms in intercultured crop (double lines) compared to single line (6%). Whereas, observations showed 9% stalks damage by maize borer recorded on monocropping grown maize (DF= 2, F= 81.00, P= 0.0006, SE= 0.471).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eGrain yield\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eData concerning crop yields (Table 4), reflected that intercropping pattern had significant effects on this parameter. Minimum yield was obtained in canola (484.40 gm/ 3.5 m\u003csup\u003e2\u003c/sup\u003e) (1384. 00 kg/ hec) and maize (836.70 gm/ 3.5 m\u003csup\u003e2\u003c/sup\u003e) (2390.57 kg/ hec) planted alone which differed significantly from rest of treatments (DF= 2, F= 18.29, P= 0.0097, SE=\u0026nbsp;31.941). Canola planted with double row of maize intercropping appeared to be the most productive practice obtaining (675.20 gm/ 3.5 m\u003csup\u003e2\u003c/sup\u003e) (1929.14 kg/ hec) \u0026amp; (1089.00 gm/ 3.5 m\u003csup\u003e2\u003c/sup\u003e) (3111.42\u0026nbsp;kg/ hec) yield, and remained more profitable than single row plating (553.50 gm/ 3.5 m\u003csup\u003e2\u003c/sup\u003e) (1581.42 kg/ hec) \u0026amp; (880.80 gm/ 3.5 m\u003csup\u003e2\u003c/sup\u003e) (2516.57 kg/ hec), respectively (DF= 2, F= 130.29, P= 0.0002, SE= 16.742).\u0026nbsp;\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eDuring present experimentation, the goal achieved was the significance of maize crop as a reservoir of beetle predators from environmentally adverse factors. This attraction to predatory insect may be olfactory or visual; however, additional plant characteristics such as surface chemicals may present additional cues that stimulated predator\u0026rsquo;s attraction. These findings are supported by the observations of Grevstad and Klepetka (1992) who reported about the movement of adult conccinellids on crucifers and suggested that movement along leaf edges and stems was more efficient and the risk of falling from the plant remained very rare. Obata (1997), and Griffin and Yeargan (2002) suggested that lady beetles \u003cem\u003eHarmonia\u003c/em\u003e and \u003cem\u003eColeomegilla\u003c/em\u003e (Coccinellid) used olfactory and visual cues to detect their prey. The manipulations of such predator\u0026rsquo;s reservoirs had been emphasized since longtime, for instance, Forbes (1883) noted coccinellid species feed on maize pollens. Bosch and Telford (1970) suggested that cultivation of corn served as host to many insect species, which were ideal for the reproduction of entomophagous insects. Stary (1987) was also of the same opinion for the establishment of parasitoid reservoirs. So, the intercrop plantation can affect predaceous arthropods abundance and behavior to enhance the number of predators, otherwise, their exposure to cold and short day length could hasten dormancy or enhance dispersal, but the presence of maize retarded such environmental constraints. The lower number of aphids on double row planting could be because of maize\u0026rsquo;s capacity to hold maximum coccinellid predators and their more severe competition for feeding on aphid prey, as compared to single row planting. These results are somewhat in agreement with Gliessmann (1987), who for aphid control in brassica crops exploited the crop-weed associations like \u003cem\u003eChenopodium album\u003c/em\u003e Linnaeus\u003cem\u003e.\u003c/em\u003e Amjad et al. (1987) suggested that mass-reared individuals of \u003cem\u003eC. septempuctata\u003c/em\u003e should be released when crop is at flowering, as this stage was most susceptible to damage by aphids. Kyamanywa and Tukahirwa (1988), and Ekesi et al. (1999) conducted field experiments to assess the combined effects of intercropping cowpea with maize inoculated with fungus. Results suggested that pest density and damage were significantly lower in intercrop than in the monocrop. Stary and Gonzalyez (1991) evaluated positive roles of \u003cem\u003eC. album\u003c/em\u003e occurring both on farm land and urban environments in presenting reservoirs of useful parasitoids for aphid control. Bianchi et al. (2007) analyzed whether changes in crop selection could explain the dramatic and unexplained decline in abundance of the ladybeetle \u003cem\u003eC. septempunctata\u003c/em\u003e. The results indicated that the population viability of \u003cem\u003eC. septempunctata\u003c/em\u003e was highly dependent on availability of aphid prey in crops, in particular cereal, which served as their major reproduction habitat.\u003c/p\u003e\n\u003cp\u003eThe current results revealed that maximum yield was recorded for canola and double maize lining, which can mainly be attributed to their holding the maximum number of predators to suppress the aphid. Atwal (1976) pointed out that owing to the very high population of aphid, the developing pods did not produce healthy seeds and yield of infested crop was reduced to one fourth or one fifth. Additionally, thigh yield was due to less competition among crop plants for nutrients, moisture, light and space for survival, and both the crop plants fully utilized available resources. Further,\u0026nbsp;plant quality traits and flower\u0026nbsp;attributes were typical in intercrops. A parallel statement was made by\u0026nbsp;Cresswell\u0026nbsp;et al.\u0026nbsp;(2001)\u0026nbsp;that none of the attributes of individual \u003cem\u003eB. napus\u003c/em\u003e flower (petal length, petal width, stamen length, pistil length, pollen production, diameter of pollen grains and nectar production) varied with plant density. In the face of resource scarcity, the plants apparently conserved flower size. Sampling\u0026nbsp;for maize borer attack on maize crop showed that infestation was lower on intercultured than monocropping. These observations are supported by the findings of Jotwani and Verma (1969) who reported that aphidophagus coccinallids also feed on non-aphid hosts including sorghum stem borer. Similarly, Andow (1990) found coccinellid species feeding on lepidopterous eggs and larvae. In field experiments, studies conducted by Kurmvanshi et al. (1994) on intercropping of oilseeds and pulses with wheat concluded that wheat grown between maize and soyabean strips improved soyabean production over the two-crop systems without adversely affecting wheat yields. Moreover, Du\u003cem\u003e\u0026nbsp;\u003c/em\u003eet al. (2004) investigated that allelochemical contents should be taken into account in integrated pest management for their effects on both herbivores and entomophagous insects. \u003cstrong\u003eWang\u003c/strong\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003eet al. (2009) evaluated the effects of intercropping of wheat cultivars and oilseed rape on the densities of wheat aphid, \u003cem\u003eSitobion avenae\u003c/em\u003e (Fabricius), and their arthropod natural enemies. The results showed that the densities of \u003cem\u003eS. avenae\u003c/em\u003e were significantly higher on the monoculture pattern than on either the 8-2 intercropping pattern (eight rows of wheat with two rows of oilseed rape) or the 8-4 intercropping pattern (eight rows of wheat with four rows of oilseed rape). The mean number of predators (ladybeetles) and the parasitization rates of \u003cem\u003eS. avenae\u003c/em\u003e were significantly higher in two intercropping patterns than those in the monoculture pattern. The results showed that wheat-oilseed rape intercropping conserved more predators and parasitoids than in wheat monoculture fields. Li et al.\u003cem\u003e\u0026nbsp;\u003c/em\u003e(1994) studied the relationships among wheat aphids, their natural enemies and wheat yield loss. Yield losses were significantly correlated with the population densities of pests \u003cem\u003eS. avenae\u003c/em\u003e and \u003cem\u003eRhopalosiphum padi\u003c/em\u003e Linnaeus and predator \u003cem\u003eC. septempunctata\u003c/em\u003e. However, the results of Ali et al.\u003cem\u003e\u0026nbsp;\u003c/em\u003e(2000) revealed that canola grown with one row of wheat produced the highest canola seed yield.\u003c/p\u003e\n\u003cp\u003eIntercropping was found to reduce aphid\u0026rsquo;s density compared with monoculture. Furthermore, natural enemies, in this case mainly predators, significantly reduced the numbers of aphids, showing that it is possible to retain the predation pressure in intercropped systems. Hence, the intercrop disrupts herbivorous insect pest, reduces insect damage as the insects are more\u0026nbsp;abundant on\u0026nbsp;an alternative host, and diverse habitats attract and retain more enemies of insect pests compared with a monoculture. Thus, adding more plant species to a system affect herbivores in two major ways; firstly, the environment of the host plants (e.g.,\u003cem\u003e\u0026nbsp;\u003c/em\u003eneighboring plants and microclimatic conditions), are altered, and secondly, host plant quality (e.g.,\u003cem\u003e\u0026nbsp;\u003c/em\u003emorphology and chemical content), are changed (Langer\u0026nbsp;et al.\u0026nbsp;2007). Changes in environment and host plant quality lead to direct effects on the host plant searching behavior of herbivorous insects, as well as indirect effects on their developmental rates and on interactions with natural enemies (Bukowinsky\u0026nbsp;et al.\u003cem\u003e\u0026nbsp;\u003c/em\u003e2004). The mechanism behind the direct effects of intercropping states that when an herbivorous insect lands on an intercrop plant instead of a host plant, its behavioral sequence is disrupted (Finch and Collier 2000). The control crops, often a pure stand of host plants, then function as a trap crop, suffering higher herbivore densities and damage (Bommarco and Banks 2003). The indirect consequences of intercropping include effects on the natural enemy\u0026rsquo;s community. The effect of natural enemies is enhanced in mixed cropping systems, because these systems provide a variety of microhabitats and alternative prey (Root 1973). Besides an alteration in the host plant environment of intercropping systems directly affecting herbivore behavior, crop plants in intercropping systems often compete with the intercrop for resources such as light, water and nutrients. These factors may have consequences for plant growth (Ramert 1996), morphology (Hooks and Johnson 2001), and chemical composition (Osier and Jennings 2007), which in turn could affect host plant finding and acceptance by herbivores (Den Belder et al. 2000). Indirectly, this might also change the suitability of the crop plant as a food source for insect herbivores (Simpson and Raubenheimer 1995), which could have consequences for their development rates (Bukowinsky et al. 2004; Osier and Jennings 2007). Among plant quality traits found to affect herbivore development are their fiber and nutrient contents (Hochuli, 1993), which can both be affected by environmental conditions (Osier and Jennings 2007), and might therefore be expected to vary between monocultured and intercropped plants. On the other hand, the resource competition may limit the ability of a plant to defend itself from natural enemies, leading to greater herbivory on \u003cem\u003eB. napus\u003c/em\u003e plants (Cipollini and Bergelson 2002).\u003c/p\u003e\n\u003cp\u003eThe overall results of current research work showed that abiotic factors like relative humidity and temperature also contribute on the population fluctuation of insects. Li et al. (1994) found that numbers of natural enemies were correlated with certain abiotic factors such as mean temperature, relative humidity and rainfall. Lactin et al. (1995) studied that in general, the relationship between insect development rate and temperature was curvilinear, this information may be used to estimate whether that location will provide sufficient physiological time for a particular insect species to complete its development and to lay a full complement of eggs. Thus, in this cropping system, natural enemies as well as abiotic factors played a greater role in shaping the population dynamics of insects. These results can be used to guide the selection of biocontrol agents for release and the selection of release sites may be successful in pest control. The use of climatic conditions to predict possible areas of establishment has several benefits in pest control programs. Suitable climatic conditions can avoid the waste of effort involved in continuing the attempts to establish an agent which is not adapted to local climatic conditions; suggest a change in release strategy for an agent which did not establish from initial releases; and provide encouragement to continue with releases of an agent (Sarwar and Saqib 2010; Sarwar 2016c; Sarwar and Roohi, 2020). Since, this study has been initiated to use in pest management strategy, the predator preferred host plants like maize could be grown as intercrop, it can either be harvested for fodder, or otherwise be kept as grain crop. Alternatively, border plantation of maize around rape and mustard fields is recommended to enhance aphid\u0026rsquo;s predation by coccinellids.\u0026nbsp;\u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003eIn reducing the need for chemicals, current research efforts initiated achieved the goal of natural enemy\u0026rsquo;s conservation by focusing on the role of intercropping through planting of more than one crop in close proximity as part of the same farming system. Demonstrated advantages of intercropped maize plants displayed a reduction in aphid\u0026rsquo;s and maize borer\u0026rsquo;s populations enlightened by attracting higher numbers of lady beetle predators for organic farming. Additionally, the compatibility of intercropping with pest management strategy can reduce the disruption of natural enemies along with promoting biodiversity and sustaining environmental quality. It is emphasized that canola-maize intercropping can successfully be practiced without any intercrop competition. Such intercropping can also modify the microclimate of crop fields making them more favorable for parasitoids. For pest control, all the considerations including any attractive feature of plant that is acceptable for entomophagous insects must be weighed while deciding the cropping system. It is predicted that such natural enemies\u0026rsquo; conservation practices in some form could be a part of innovative integrated pest management strategies in holistic framework and consonant with farmer\u0026rsquo;s socioeconomic circumstances. Nevertheless, reduced pest intensities and increased grain yield obtained from the intercrops, could offer multiple benefits and adoption of this important tool would have very positive implications for the farmers in sustainable agriculture.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e This research received no external funding.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e The author acknowledges the staff members for sampling and data collection.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u0026nbsp;\u003c/strong\u003eAll data of the study have been presented in the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDeclarations\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflicts of Interest:\u003c/strong\u003e No potential conflict of interest is reported by the author of this article.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eAlford DV, Nilsson C, Ulber B (2003) Insect Pests of Oilseed Rape Crops. 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Ind J Agron 42: 201-204.\u003c/li\u003e\n \u003cli\u003e\u003cstrong\u003eWang W, Liu Y, Chen J, Ji X, Zhou H,\u003c/strong\u003e \u003cstrong\u003eWang G\u003c/strong\u003e (\u003cstrong\u003e2009\u003c/strong\u003e)\u0026nbsp;Impact of intercropping aphid-resistant wheat cultivars with oilseed rape on wheat aphid (\u003cem\u003eSitobion avenae\u003c/em\u003e) and its natural enemies. Acta Ecol. Sin 29 (3): 186-191.\u003c/li\u003e\n \u003cli\u003eWeber G (1985) Genetic variability in host plant adaptation of the green peach aphid, \u003cem\u003eMyzus persicae.\u003c/em\u003e Entomol Exp Appl 38 (1): 49-56.\u003c/li\u003e\n \u003cli\u003eWright EJ, laing JE (1982) Stage specific mortality of \u003cem\u003eColeomegilla maculate lengi\u0026nbsp;\u003c/em\u003eTimberlake on corn in southern Ontario. Environ Entomol\u003cem\u003e\u0026nbsp;\u003c/em\u003e11: 32-37.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Tables","content":"\u003cp\u003e\u003cstrong\u003eTable 1\u003c/strong\u003e Percent species composition of coccinellid lady beetles and aphids in experimental field on canola and maize\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"625\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003eInsect\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003eName of species\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003ePercent \u0026nbsp;composition\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003ePredator\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003eZigzag beetle \u003cem\u003eCheilomenes sexmaculata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e50 a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003e11-Spotted lady beetle \u003cem\u003eCoccinella undecimpunctata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e30 b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003e7-Spotted lady beetle \u003cem\u003eCoccinella septempunctata\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e20 b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 451px;\"\u003e\n \u003cp\u003eStandard Error\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e7.071\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"3\" valign=\"top\" style=\"width: 73px;\"\u003e\n \u003cp\u003ePest\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003eGreen peach aphid\u0026nbsp;\u003cem\u003eMyzus persicae\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e70.00 a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003eTurnip aphid \u003cem\u003eLipaphis erysimi\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e20.00 b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 378px;\"\u003e\n \u003cp\u003eCabbage aphid \u003cem\u003eBrevicoryne brassicae\u003c/em\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e10.00 c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 451px;\"\u003e\n \u003cp\u003eStandard Error\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 174px;\"\u003e\n \u003cp\u003e2.357\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eDifferent alphabetical letters in column denote statistical significance values at alpha 0.05.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 2\u003c/strong\u003e Meteorological data during the year 2021-2022 at experimental field\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"643\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eYear/\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 327px;\"\u003e\n \u003cp\u003eTemperature (\u003csup\u003e0\u003c/sup\u003eC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003eR. H. %\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eMonth 2021-2022\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003eMinimum (\u003csup\u003e0\u003c/sup\u003eC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003eMaximum (\u003csup\u003e0\u003c/sup\u003eC)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e\u003cstrong\u003e\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eNovember\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e14.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e31.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e59.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eDecember\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e10.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e26.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e72.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eJanuary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e8.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e25.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e68.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eFebruary\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e27.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e58.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eMarch\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e16.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e34.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e52.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eApril\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e22.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e40.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e53.0\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 188px;\"\u003e\n \u003cp\u003eMean\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 157px;\"\u003e\n \u003cp\u003e13.75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 170px;\"\u003e\n \u003cp\u003e30.82\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 128px;\"\u003e\n \u003cp\u003e60.33\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 3\u003c/strong\u003e Mean numbers of aphids and adult ladybird beetles on canola and maize crops\u003c/p\u003e\n\u003ctable border=\"1\" cellspacing=\"0\" cellpadding=\"0\" width=\"661\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 227px;\"\u003e\n \u003cp\u003eCanola\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"3\" valign=\"top\" style=\"width: 273px;\"\u003e\n \u003cp\u003eMaize\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003eAphid number/ plant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003ePredator\u003c/p\u003e\n \u003cp\u003e(Lady beetle) number/ plant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003eAphid number/\u003c/p\u003e\n \u003cp\u003ePlant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003ePredator\u003c/p\u003e\n \u003cp\u003e(Lady beetle) number/ plant\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003eMaize borer infestation (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003eT\u003csub\u003e1\u003c/sub\u003e = Canola/ Maize alone (Control)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e60.16 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.16 c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e59.86 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e1.33 c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e9.00 a\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003eT\u003csub\u003e2\u003c/sub\u003e = Canola + single line of maize\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e41.86 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.66 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e37.40 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e2.16 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e6.00 b\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003eT\u003csub\u003e3\u003c/sub\u003e = Canola + double line of maize\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e28.60 c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.79 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e22.16 c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e3.00 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e3.00 c\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 161px;\"\u003e\n \u003cp\u003eStandard Error\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 104px;\"\u003e\n \u003cp\u003e1.694\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 123px;\"\u003e\n \u003cp\u003e0.0094\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 69px;\"\u003e\n \u003cp\u003e4.849\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 110px;\"\u003e\n \u003cp\u003e0.448\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 94px;\"\u003e\n \u003cp\u003e0.471\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003eDifferent alphabetical letters in same column denote statistical significance values at alpha 0.05.\u003c/p\u003e\n\u003cp\u003e\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eTable 4\u003c/strong\u003e Mean seed yield of canola and maize crops at experimental field\u003c/p\u003e\n\u003ctable border=\"0\" cellspacing=\"0\" cellpadding=\"0\" width=\"649\"\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd rowspan=\"2\" valign=\"top\" style=\"width: 258px;\"\u003e\n \u003cp\u003eTreatments\u003c/p\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 204px;\"\u003e\n \u003cp\u003eCanola\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd colspan=\"2\" valign=\"top\" style=\"width: 187px;\"\u003e\n \u003cp\u003eMaize\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003eYield / plot\u003c/p\u003e\n \u003cp\u003e(3.5 m\u003csup\u003e2\u003c/sup\u003e) (gm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003eYield/\u003c/p\u003e\n \u003cp\u003eHectare\u003c/p\u003e\n \u003cp\u003e(Kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003eYield/ plot\u003c/p\u003e\n \u003cp\u003e(3.5 m\u003csup\u003e2\u003c/sup\u003e) (gm)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003eYield/ Hectare\u003c/p\u003e\n \u003cp\u003e(Kg)\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 258px;\"\u003e\n \u003cp\u003eT\u003csub\u003e1\u003c/sub\u003e = Canola/ Maize alone (Control)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e484.40 c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e1384. 00\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e836.70 c\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e2390.57\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 258px;\"\u003e\n \u003cp\u003eT\u003csub\u003e2\u003c/sub\u003e = Canola + single line of maize\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e553.50 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e1581.42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e880.80 b\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e2516.57\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 258px;\"\u003e\n \u003cp\u003eT\u003csub\u003e3\u003c/sub\u003e = Canola + double line of maize\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e675.20 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e1929.14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e1089.00 a\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e3111.42\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd valign=\"top\" style=\"width: 258px;\"\u003e\n \u003cp\u003eStandard Error\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 108px;\"\u003e\n \u003cp\u003e31.941\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 96px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 101px;\"\u003e\n \u003cp\u003e16.742\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd valign=\"top\" style=\"width: 85px;\"\u003e\n \u003cp\u003e\u0026nbsp;\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u0026nbsp;Different alphabetical letters in same column denote statistical significance values at alpha 0.05.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"international-journal-of-tropical-insect-science","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jtis","sideBox":"Learn more about [International Journal of Tropical Insect Science](http://link.springer.com/journal/42690)","snPcode":"42690","submissionUrl":"https://www.editorialmanager.com/jtis/default2.aspx","title":"International Journal of Tropical Insect Science","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"Aphid. Canola. Maize. Coccinellid. Conservation. Intercropping","lastPublishedDoi":"10.21203/rs.3.rs-6794268/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6794268/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"Experiments were made on the feasibility of canola-based maize intercropping to observe population and conservation of aphidophagous ladybird beetles and their ultimate impacts on aphid’s density and crop yield. Experimental treatments were, canola 4 rows+ maize single row, canola 4 rows+ maize double row intercropping, and their comparison with canola and maize grown alone to generate data whether these combinations had encouraging or discouraging influences on useful and harmful insect populations. The striking result of this study was impacts of maize intercropping to enhance predators and suppress the pests populations. Data on populations of aphid and maize borer had shown significantly more numbers of pests noted in treatment of canola and maize, respectively, planted alone compared to canola intercropped with double rows of maize. Double lines of maize plus canola intercropping gave better results than single line for holding higher predator populations. Results achieved indicated that canola and double row maize intercropping generated better conservation of coccinellid beetles for aphid or borer control than single row maize and check treatment, and yielded higher produce. This could be attributed due to the capacity of double row maize planting to hold maximum numbers of ladybird beetles and their more severe competition to predate upon the pests prey. And owing to low level of pest populations on intercropped canola and maize plantings, these produced significantly higher seed yields. The predominant emerging observation was that the intercropped maize exhibited proficient shelter and roosting sites for coccinellids during peak winter season, which was a remedy against hibernation and dispersion constraints upon these predators. Based on the outcomes made during current experiment, the implications of existing knowledge and prospects would facilitate implementation of intercropping strategy to enhance suppression of insect pests.","manuscriptTitle":"Manipulation of intercropping technology for conservation of predaceous ladybird beetles (Coleoptera: Coccinellidae) to aphids (Hemiptera: Aphididae) management","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-30 08:16:12","doi":"10.21203/rs.3.rs-6794268/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Major revisions","date":"2026-02-10T10:43:31+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"","date":"2025-06-26T09:46:02+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-06-26T09:35:45+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-26T03:39:31+00:00","index":"","fulltext":""},{"type":"submitted","content":"International Journal of Tropical Insect Science","date":"2025-06-22T07:21:52+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"international-journal-of-tropical-insect-science","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jtis","sideBox":"Learn more about [International Journal of Tropical Insect Science](http://link.springer.com/journal/42690)","snPcode":"42690","submissionUrl":"https://www.editorialmanager.com/jtis/default2.aspx","title":"International Journal of Tropical Insect Science","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"2cf9eb7e-4bd3-42f8-8104-47ba402f33fa","owner":[],"postedDate":"June 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2026-03-27T12:15:16+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-30 08:16:12","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6794268","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6794268","identity":"rs-6794268","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}