Investigation of host plant resistance mechanisms in chilli against black thrips, Thrips parvispinus (Karny)

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Vijaykumar, N Kiran Kumar, G. Somu, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7151468/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 07 Nov, 2025 Read the published version in International Journal of Tropical Insect Science → Version 1 posted 14 You are reading this latest preprint version Abstract Thrips parvispinus (Karny) (Thysanoptera: Thripidae) is a recently invasive and highly polyphagous pest species causing significant damage to chilli ( Capsicum spp .) and other economically important crops in India and worldwide. Despite its quarantine significance, limited studies exist on the biochemical factors influencing its infestation dynamics on different chilli hybrids. This study was conducted during Summer 2024 at the College of Agriculture, V. C. Farm, Mandya, Karnataka, India, to assess the biochemical traits of chilli leaves that affect T. parvispinus infestation under field conditions. Biochemical profiling at 60 days after transplanting (DAT) revealed that infestation levels were positively correlated with soluble sugars, reducing sugars, and crude protein content, indicating that nutrient-rich tissues favor thrips population growth. Conversely, defensive phytochemicals such as total phenols, free amino acids, and tannins showed strong negative correlations with thrips infestation, suggesting their role in host resistance by deterring feeding and reproduction. These findings provide valuable insights into the biochemical basis of host susceptibility and resistance, informing the development of chilli hybrids with enhanced defensive traits and integrated pest management strategies to mitigate the impact of T. parvispinus on chilli production. Thrips parvispinus Chilli Host plant resistance Pest infestation dynamics Biochemical components Figures Figure 1 Introduction Thrips parvispinus (Karny), commonly known as the invasive black flower thrips, has recently emerged as a major threat to chilli ( Capsicum spp .) production in India, causing significant economic losses and posing challenges to sustainable cultivation. Since its first report in India on Carica papaya in Bengaluru (Tyagi et al., 2015 ), T. parvispinus has expanded its host range to include several economically important crops such as chilli, beans, eggplant, pepper, potato, shallot, strawberry, and ornamentals like Brugmansia and Dahlia (Rachana et al., 2018 ; Roselin et al., 2021 ; NPPO, 2019). This polyphagous pest is predominantly found on white, fragrant flowers where it feeds on pollen, causing characteristic brownish streaks on petals, flower drop, and ultimately, a drastic reduction in fruit yield and quality. Infestation leads to malformed fruits with button-shaped or rugged surfaces, severely impacting marketability (Maharijaya et al., 2011 ; Hutasoit et al., 2019 ). The pests biology shows adults exhibiting peak flight activity in the morning, preferring flowers, while nymphs inhabit leaves, complicating management strategies (Pratiwi et al., 2018 ). The complex thrips fauna in chilli ecosystems makes accurate identification and monitoring of T. parvispinus difficult but essential for effective pest management (Palanisamy et al., 2023 ). Biochemical factors, particularly plant secondary metabolites such as phenolics, tannins, and free amino acids, play a pivotal role in host plant resistance by influencing thrips behavior, feeding, and reproduction. Phenolic compounds act as antixenotic agents, deterring thrips feeding and oviposition, while tannins reduce nutrient availability and disrupt insect digestion, thereby limiting pest proliferation (Panda and Khush, 1995 ; Bharathi, 1996 ; Pathak and Saxena, 1976). Understanding these biochemical interactions is critical to developing resistant chilli cultivars and integrated pest management (IPM) strategies. Materials and Methods Experimental details The study was conducted during summer 2024 at the College of Agriculture, V. C. Farm, Mandya, Karnataka, situated in the Southern Dry Zone (Zone-6). Thirty-two chilli ( Capsicum annuum L. ) hybrids, including susceptible checks such as ‘Byadgi Kaddi’, were evaluated for response to T. parvispinus under field conditions. Thirty-day-old seedlings were transplanted in a randomized complete block design with three replications, maintaining 60 cm × 45 cm spacing. Standard agronomic practices, including uniform fertilizer application and irrigation, were followed as per University of Agricultural Sciences, Bengaluru recommendations (Anonymous, 2022 ). Assessment of thrips infestation and biochemical analysis Thrips infestation and plant response were monitored regularly throughout the crop growth period. Leaf curl index, an indicator of thrips damage, was recorded following Niles (1980). For biochemical analysis, uninfested top leaves were collected at 60 days after transplanting (DAT) during summer 2024 from two representative hybrids per resistance category identified via preliminary screening over two seasons. Twelve hybrids, including susceptible checks such as ‘Byadgi Kaddi’, were selected. Samples were analyzed for total sugars, reducing sugars, total phenols, tannins, crude protein, and free amino acids using standard protocols. Biochemical components and their roles in plant defense and nutrition The biochemical components analyzed in this study play crucial roles in plant defense and nutrition. Total sugars, estimated using the Somogyi ( 1952 ) method, serve as attractants to herbivores and are vital for plant growth and maintaining nutritional balance (Jeandet et al., 2022 ). Reducing sugars, also determined by the Somogyi method, influence the nutritional quality of plants, attract herbivores, and mediate defense responses (Khatri and Chhetri, 2020 ). Total phenols, quantified by the Folin–Ciocalteau method, function as deterrents and antifeedants that adversely affect insect reproduction and growth (Dai and Mumper, 2010 ). Crude protein content, measured by the Micro-Kjeldahl method, contributes to the nutritional profile through amino acid composition and can influence herbivore attraction (Robbins et al., 1987 ). Total free amino acids, assessed using the ninhydrin method, play a dual role by attracting natural enemies of pests and mediating plant defensive responses (Baqir et al., 2019 ). Lastly, tannins, estimated through the Folin-Denis method, impact herbivore behavior by affecting egg-laying, digestion, and physiology and impart an astringent taste that serves as a feeding deterrent (Hassanpour et al., 2011 ). Together, these biochemical constituents mediate complex interactions between plants and herbivorous insects and are integral to developing pest-resistant cultivars. Statistical analysis The mean data on biochemical and nutritional factors was worked out for each test hybrid representing different resistance categories, and the data was subjected to ANOVA (Gomez and Gomez, 1984 ; Hoshmand, 1988 ) after suitable statistical transmission (Arc sin) and means was separated by Tukey’s HSD (Tukey 1965 ) for tabulation and interpretation. Further, the data on per cent leaf curl index (PLI) and plant biochemicals in each test hybrid were subjected to the Multiple Linear Regression analysis technique (MLR) (Panse and Sukhathme,1967) by fitting different functions using the software “SAS-Syntex Reference Guide 2016, version 16 (SPS16), South Whacker Drive, Chicago, IL.” Results and Discussion The studies on various biochemical and nutrient factors associated with the resistance and susceptibility of chilli hybrids against the black thrips were conducted during Summer 2024 and the results are presented here. Total Phenols Total phenol content showed a decreasing trend with increased susceptibility of chilli hybrids to Thrips parvispinus , ranging from 3.91 mg g⁻¹ in resistant to 1.44 mg g⁻¹ in susceptible genotypes (Table 1 ). Resistant hybrids Iravata and Meenakshi recorded the highest phenol levels (3.91 and 3.75 mg g⁻¹), while moderately resistant hybrids Kalavathi and Dolphin had 3.69 and 3.44 mg g⁻¹, respectively. Moderately susceptible hybrids (Rakshak, Praveen, Pithamber) showed intermediate phenol content (2.8–3.1 mg g⁻¹), and susceptible genotypes such as Akshaya-22 and ARD lines exhibited lower values (2.22–2.59 mg g⁻¹). The lowest phenol levels were recorded in highly susceptible Kavitha, KGF-2, and susceptible check Byadagi Kaddi (1.44–1.86 mg g⁻¹). Correlation analysis revealed a strong negative association between total phenols and leaf curl incidence (r = − 0.98**, Fig. 1 ). Table 1 Biochemical constituents of chilli hybrids associated with resistance to chilli black thrips, T. parvispinus at 60 DAT during, Summer 2024 Sl. No. Category Hybrids PLI (%) Biochemical components (mg g -1 ) Total Phenols Total soluble sugars Total reducing sugars Crude proteins Total free amino acid Tannins 1 R Iravata 6.00 (14.18) 3.91 a 2.84 n 1.36 l 3.88 g 19.97 a 4.23 a 2 Meenakshi 6.67 (14.97) 3.75 b 2.75 m 1.46 k 3.26 h 19.57 b 4.17 b 3 MR Kalavathi 15.67 (23.32) 3.69 b 3.07 l 1.55 j 3.95 g 19.4 b 3.92 c 4 Dolphin 19.33 (26.08) 3.44 c 3.14 k 1.70 i 5.05 f 18.78 c 3.87 c 5 MS Rakshak 23.67 (29.11) 3.12 d 3.76 j 1.96 h 5.45 ef 18.51 cd 3.58 e 6 Praveen 28.00 (31.95) 2.96 de 3.92 i 2.16 g 5.87 de 17.92 e 3.41 f 7 Pithamber 30.00 (33.21) 2.84 e 4.13 h 2.36 f 6.19 cd 17.54 f 3.26 g 8 S Akshaya-22 34.33 (35.87) 2.59 f 4.30 g 2.58 e 6.09 d 17.08 g 3.18 h 9 ARD-5555 38.33 (38.25) 2.34 g 4.67 f 2.78 d 6.70 bc 16.51 h 3.15 hi 10 ARD-499 44.33 (41.74) 2.22 g 4.86 e 2.81 d 6.38 cd 16.09 i 3.12 i 11 HS Kavitha 57.33 (48.64) 1.86 h 5.22 c 2.98 bc 7.23 ab 15.77 ij 2.84 k 12 KGF-2 56.67 (48.83) 1.69 i 5.34 b 3.01 b 7.22 ab 15.49 j 2.52 l 11 SC Byadagi kaddi 68.87 (56.09) 1.44 j 6.52 a 3.13 a 7.58 a 14.17 k 2.33 m SE m ± 2.81 0.03 0.02 0.08 0.07 0.04 0.14 CD @ p = 0.01 8.54 0.11 0.07 0.26 0.22 0.13 0.40 Figures in the parenthesis indicate arcsine transformed values; Values in the column followed by common letters are non-significant at p = 0.05 as per Tukey’s HSD (Tukey, 1965 ); R- Resistant; MR- Moderately resistant; MS- Moderately MS- Moderately susceptible; S- Susceptible; SC- Susceptible check. These findings corroborate earlier studies in chilli and related crops where phenolic compounds were reported as key antixenotic factors conferring resistance to thrips and other insect pests by Subhash et al. ( 2013 ), Vijaykumar et al. ( 2015a , 2015b , 2022 ), Prasannakumar et al. ( 2015 ), and Jyothi et al. ( 2018 ). Phenolics act as feeding deterrents and reduce insect fecundity by interfering with digestion and nutrient assimilation, thus limiting pest population buildup. Similar negative correlations between total phenols and thrips infestation have been reported in Scirtothrips dorsalis on chilli (Chaudhary and Pandya, 2019 ) and other host-pest systems. Therefore, total phenol content serves as a reliable biochemical marker for host plant resistance to T. parvispinus . Integration of phenolic profiling in chilli breeding programmes could facilitate the development of thrips-resistant cultivars, contributing to sustainable pest management. Total soluble sugars (TSS) Significant variation in total soluble sugar (TSS) content was observed among the chilli hybrids, ranging from 2.75 mg g⁻¹ in resistant to 6.52 mg g⁻¹ in susceptible genotypes (Table 1 ). Resistant hybrids, Iravata and Meenakshi, recorded the lowest TSS levels (2.84 and 2.75 mg g⁻¹, respectively), while moderately resistant hybrids Kalavathi and Dolphin had slightly higher values (3.07 and 3.14 mg g⁻¹). Moderately susceptible hybrids (Rakshak, Praveen, Pithamber) exhibited intermediate TSS content (3.76–4.13 mg g⁻¹). Susceptible hybrids, including Akshaya-22, ARD-5555, ARD-499, Kavitha, and KGF-2, showed progressively higher TSS levels, with the susceptible check Byadagi Kaddi recording the maximum (6.52 mg g⁻¹). Correlation analysis revealed a strong positive influence of TSS on leaf curl incidence (r = 0.98**, Fig. 1 ). These findings are consistent with previous reports linking higher sugar content to increased thrips infestation in chilli (Rameash et al., 2015 ) and other crops (Roopa, 2013 ; Subhash et al., 2013 ; Chaudhary and Pandya, 2019 ). Sugars are essential nutrients and energy sources for insects, and their elevated presence may enhance host suitability and act as feeding stimulants, thereby increasing pest attraction and colonization (Mittler and Dadd, 1962 ; Corcuera, 1993; Nawalgatti et al., 1999). This positive correlation between total sugar content and susceptibility has been observed across various host-pest interactions, including rice genotypes and different insect pests like gall midge, leaf folder, and brown planthopper (Vijaykumar et al., 2009, 2012; Vanitha et al., 2015 ; Ashrith et al., 2017 ). This supports the theory of co-evolution where lower nutritional quality, in terms of accessible sugars, serves as a chemical defense mechanism against herbivory. Total reducing sugars (TRS) Significant variation in total reducing sugar content was observed among the chilli hybrids, ranging from 1.36 to 3.13 mg g⁻¹ (Table 1 ). Resistant hybrids Iravata and Meenakshi recorded the lowest reducing sugars of 1.36 and 1.46 mg g⁻¹, respectively, while moderately resistant hybrids Kalavathi and Dolphin exhibited slightly higher values of 1.55 and 1.70 mg g⁻¹. Moderately susceptible hybrids Rakshak, Praveen, and Pithamber showed intermediate levels (1.96–2.36 mg g⁻¹), whereas susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 ranged from 2.58 to 2.81 mg g⁻¹. Highly susceptible Kavitha and KGF-2 recorded 2.98 and 3.01 mg g⁻¹, respectively, with the susceptible check Byadgi Kaddi having the highest amount of 3.13 mg g⁻¹. Correlation analysis demonstrated a strong positive relationship between total reducing sugars and leaf curl incidence caused by T. parvispinus at 60 days after transplanting (r = 0.95**, Fig. 1 ). These results concur with findings by Praveen et al. ( 2022 ), who reported lower reducing sugar content in resistant chilli germplasm compared to susceptible lines, with the highest reducing sugars recorded in the susceptible check Byadgi Kaddi. Reducing sugars, including oligosaccharides and monosaccharides, serve as essential nutrients for insect pests and act as feeding stimulants due to their sweetness, thereby enhancing pest infestation. Several studies have similarly observed lower reducing sugar levels in resistant germplasm of Scirtothrips dorsalis and documented a positive correlation between reducing sugar content and thrips infestation (Varadharajan and Veeravel, 1996 ; Megharaj et al., 2016 ; Chaudhary and Pandya, 2019 ; Subhash et al., 2013 ). The present findings thus reinforce the role of reducing sugars as biochemical factors influencing host susceptibility to thrips. Crude proteins Significant variation in crude protein content was observed among the chilli hybrids, ranging from 3.26 to 7.58 mg g⁻¹ (Table 1 ). Resistant hybrids Iravata and Meenakshi recorded the lowest protein levels of 3.88 and 3.26 mg g⁻¹, respectively, while moderately resistant hybrids Kalavathi and Dolphin showed intermediate values of 3.95 and 5.05 mg g⁻¹. Moderately susceptible hybrids Rakshak, Praveen, and Pithamber exhibited higher protein content (5.45–6.19 mg g⁻¹), and susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 had even greater amounts (6.09–6.70 mg g⁻¹). Highly susceptible Kavitha and KGF-2 showed protein concentrations exceeding 7.20 mg g⁻¹, with the susceptible check Byadagi Kaddi registering the highest level of 7.58 mg g⁻¹. Correlation analysis indicated a significant positive relationship between crude protein content and leaf curl incidence caused by Thrips parvispinus (r = 0.93**, Fig. 1 ). These results agree with previous studies reporting lower protein content in resistant chilli germplasm compared to susceptible ones (Praveen et al., 2022 ). Proteins are vital biomolecules involved in cellular functions and plant defense signaling; changes in protein profiles often represent early responses to insect herbivory (Green and Ryan, 1972 ; Rafi et al., 1996 ; Ni et al., 2001 ). Increased protein content following insect attack has been noted as a common defense mechanism (Chen et al., 2009). However, higher total protein content has been associated with increased susceptibility to thrips (Alabi et al., 2005; Roopa, 2013 ; Chaudhary and Pandya, 2019 ). The positive correlation observed here between protein content and thrips infestation corroborates these findings, underscoring crude protein as a marker of host susceptibility. Total free amino acids (TFA) Total free amino acids (TFA) content varied significantly among the selected chilli hybrids, ranging from 14.17 to 19.97 mg g⁻¹, with a decreasing trend correlating with increased susceptibility to T. parvispinus (Table 1 ). Resistant hybrids Iravata and Meenakshi recorded the highest TFA levels (19.97 and 19.57 mg g⁻¹, respectively), statistically comparable to moderately resistant hybrids Kalavathi (19.40 mg g⁻¹) and Dolphin (18.78 mg g⁻¹). Moderately susceptible hybrids such as Rakshak, Praveen, and Pithamber had intermediate TFA contents (17.54–18.51 mg g⁻¹), while susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 showed reduced levels (16.09–17.08 mg g⁻¹). Highly susceptible genotypes Kavitha and KGF-2 recorded 15.49 and 15.77 mg g⁻¹, respectively, with the lowest TFA content found in the susceptible check Byadagi Kaddi (14.17 mg g⁻¹). Correlation analysis revealed a strong and significant negative relationship between TFA and leaf curl incidence at 60 days after transplanting (r = − 0.98**, Fig. 1 ). Free amino acids serve as essential nutrients that support insect growth, development, and reproduction by participating in protein synthesis and biogenetic pathways (Douglas, 2006). The observed negative correlation may indicate that higher TFA content enhances plant defensive metabolism, possibly through diversion of amino acids into secondary metabolites via pathways such as the phenylpropanoid route, conferring resistance to biotic stresses. Similar negative correlations between free amino acid levels and pest incidence have been reported in crops such as rice and sorghum against various pests (Vijaykumar et al., 2012; Pallavi et al., 2022 ; Megha et al., 2022 ; Punithkumar et al., 2020). This study confirms the critical role of total free amino acids as biochemical markers linked to resistance against thrips in chilli and highlights their potential utility in breeding programs aimed at enhancing pest resistance. Tannins Tannin content varied significantly among chilli hybrids, with resistant genotypes exhibiting higher levels compared to susceptible ones (Table 1 ). Resistant hybrids Iravata and Meenakshi recorded the highest tannin concentrations of 4.23 and 4.17 mg g⁻¹, respectively, while moderately resistant hybrids Kalavathi and Dolphin had slightly lower but comparable levels of 3.92 and 3.87 mg g⁻¹. Moderately susceptible hybrids Rakshak, Praveen, and Pithamber contained tannin amounts ranging from 3.26 to 3.58 mg g⁻¹. In contrast, susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 exhibited significantly reduced tannin content (~ 3.15 mg g⁻¹). Highly susceptible genotypes Kavitha and KGF-2 showed further decreased tannins (2.52–2.84 mg g⁻¹), with the susceptible check Byadagi Kaddi having the lowest level (2.33 mg g⁻¹). Correlation analysis revealed a strong negative association between tannin content and leaf curl incidence at 60 days after transplanting (r = − 0.97**, Fig. 1 ). Tannins are known to exert deleterious effects on phytophagous insects by binding to dietary proteins, reducing nutrient absorption, and causing midgut lesions that impair insect growth and development (Dubey et al., 2016 ). These polyphenolic compounds possess astringent and bitter properties that act as feeding deterrents. Mechanistically, tannins precipitate proteins, including digestive enzymes of herbivores, via hydrogen or covalent bonds with –NH₂ groups, and also chelate essential metal ions, thereby decreasing their bioavailability to pests. Consequently, tannins diminish protein digestibility and the nutritive value of plant tissues, contributing to antixenosis and resistance against thrips infestation. The present study elucidates the critical role of biochemical and nutritional factors in conferring resistance against Thrips parvispinus in chilli hybrids. Resistant genotypes were characterized by elevated levels of defensive metabolites—total phenols, tannins, and free amino acids—coupled with reduced concentrations of total soluble sugars, reducing sugars, and crude proteins. Strong and significant correlations between these biochemical constituents and thrips infestation underscore their involvement in host plant resistance. Particularly, phenolic compounds demonstrated potent antixenotic effects, positioning them as reliable biochemical markers for resistance breeding. These findings provide a robust foundation for exploiting such traits through conventional breeding and biotechnological interventions to develop thrips-resistant cultivars. Integrating these biochemical parameters into selection criteria promises a sustainable, eco-friendly strategy for thrips management, reducing reliance on chemical pesticides. Further studies are warranted to dissect the molecular mechanisms underlying these resistance traits and to validate their stability and efficacy under diverse agro-climatic conditions, thereby facilitating their adoption in chilli improvement programs. Declarations Financial Support No funding received. Conflict Of Interest The authors declare that they have no financial or non-financial conflict of interest. Author Contribution Gaurav Vinod Rao Sadafale - Conceptualization, investigation, draft preparation and analysis; L. Vijaykumar - Conceptualization, framed research proposal and draft correction; N Kiran Kumar, G. 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Ecology 68(1):98–107. https://doi.org/10.2307/1938374 Roopa HR (2013) Studies on biochemical resistance in chilli against thrips ( Scirtothrips dorsalis Hood). M.Sc. thesis, Univ Agric Sci, Bangalore, India Roselin K, Praveen P, Varatharajan K (2021) Status of invasive thrips, Thrips parvispinus Karny on chilli and its management strategies. J Trop Agric 59(2):89–96 Somogyi M (1952) Estimation of sugars by colorimetric method. J Biol Chem 200(245):89–111 Subhash BK, Khader KH, Chakravarth AK, Ashok Kumar CT, Venkataravana P (2013) Biochemical constituents influencing thrips resistance in groundnut germplasm. J Environ Biol 35:675–681 Tukey JW (1965) The technical tools of statistics. Am Stat 19(2):23–28. https://doi.org/10.1080/00031305.1965.10480929 Tyagi K, Kumar V, Singha D, Chakraborty R (2015) Morphological and DNA barcoding evidence for invasive pest thrips, Thrips parvispinus (Thripidae: Thysanoptera), newly recorded from India. J Insect Sci 15(1):105. https://doi.org/10.1093/jisesa/iev086 Vanitha BK, Kumar CTA, Kumar LV, Prashantha C (2015) Association of biochemical factors in rice against infestation of rice leaf folder, Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Pyralidae). J Exp Zool 18(1):373–376 Varadharajan S, Veeravel R (1996) Evaluation of chilli accessions resistant to thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae). Pest Manag Econ Zool 4(1-2):85–90 Vijaykumar L, Chakravarthy AK, Patil SU (2015a) Antixenosis and antibiosis component of rice resistance to Asian rice gall midge, Orseolia oryzae (Wood-Mason). In: New Horizons in Insect Science. Springer, pp 269–276. https://doi.org/10.1007/978-81-322-2089-3_24 Vijaykumar L, Chakravarthy AK, Patil SU (2015b) Impact of gall midge, Orseolia oryzae (Wood-Mason) infestation on total phenols, proline and indole acetic acid in paddy ( Oryza sativa Linn.) genotypes. In: New Horizons in Insect Science. Springer, pp 261–267. https://doi.org/10.1007/978-81-322-2089-3_23 Vijaykumar L, Patil SU, Shivanna B, Kitturmath MS (2022) Hypersensitive response and induced resistance in rice gene differentials against biotype 1 of Asian rice gall midge, Orseolia oryzae at Mandya, Karnataka. J Rice Res Dev 15(1):70–76 Additional Declarations No competing interests reported. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7151468","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":498108908,"identity":"db0af455-3055-4971-926c-5814500efdb4","order_by":0,"name":"GAURAV VINOD RAO SADAFALE","email":"data:image/png;base64,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","orcid":"","institution":"UAS Bangalore, V. C. Farm","correspondingAuthor":true,"prefix":"","firstName":"GAURAV","middleName":"VINOD RAO","lastName":"SADAFALE","suffix":""},{"id":498108909,"identity":"c2cc4c4e-2895-4c3d-a915-fc69fdbc30ca","order_by":1,"name":"L. Vijaykumar","email":"","orcid":"","institution":"UAS Bangalore, V. C. Farm","correspondingAuthor":false,"prefix":"","firstName":"L.","middleName":"","lastName":"Vijaykumar","suffix":""},{"id":498108910,"identity":"93cc07ba-cb9e-4903-9b4a-3ce73dc8487f","order_by":2,"name":"N Kiran Kumar","email":"","orcid":"","institution":"UAS Bangalore, V. C. Farm","correspondingAuthor":false,"prefix":"","firstName":"N","middleName":"Kiran","lastName":"Kumar","suffix":""},{"id":498108911,"identity":"16167e67-4e68-4347-a1db-4c9368686072","order_by":3,"name":"G. Somu","email":"","orcid":"","institution":"AICRP on Sorghum","correspondingAuthor":false,"prefix":"","firstName":"G.","middleName":"","lastName":"Somu","suffix":""},{"id":498108912,"identity":"bddda528-07fb-4caa-950f-4cc4b0a395af","order_by":4,"name":"Shivaray Navi","email":"","orcid":"","institution":"AICRP on Cotton","correspondingAuthor":false,"prefix":"","firstName":"Shivaray","middleName":"","lastName":"Navi","suffix":""},{"id":498108913,"identity":"b6b61f04-cd6f-4bde-ad10-fe684e597b67","order_by":5,"name":"Nagesh Malasiddappa Chikkarugi","email":"","orcid":"","institution":"Zonal Agricultural Research Station, V. C. Farm","correspondingAuthor":false,"prefix":"","firstName":"Nagesh","middleName":"Malasiddappa","lastName":"Chikkarugi","suffix":""}],"badges":[],"createdAt":"2025-07-17 17:53:08","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-7151468/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-7151468/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s42690-025-01624-2","type":"published","date":"2025-11-07T15:56:54+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":88858309,"identity":"c0e24069-048a-406a-bf1c-d620ba32c806","added_by":"auto","created_at":"2025-08-12 07:18:00","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":21284,"visible":true,"origin":"","legend":"\u003cp\u003eCorrelation matrix between PLI and biochemical constituents of chilli hybrids associated with resistance to chilli black thrips, \u003cem\u003eT. parvispinus\u003c/em\u003e at 60 DAT during, \u003cem\u003eSummer\u003c/em\u003e 2024\u003c/p\u003e\n\u003cp\u003eN = 13; ** Significant at P ≤ 0.01; TP- Total phenols; TSS- Total soluble sugars; TRS- Total reducing sugars; CP- Crude protein; TFAA- Total free amino acid; TA- Tannins.\u003c/p\u003e","description":"","filename":"Onlinefloatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-7151468/v1/d59aa6d1adfc4f58b867014e.png"},{"id":95564144,"identity":"9c98377e-8942-4671-b13f-3bd67fea0769","added_by":"auto","created_at":"2025-11-10 16:08:19","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":767994,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-7151468/v1/463237b5-6221-4b89-ae49-03b8512e0660.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Investigation of host plant resistance mechanisms in chilli against black thrips, Thrips parvispinus (Karny)","fulltext":[{"header":"Introduction","content":"\u003cp\u003e\u003cem\u003eThrips parvispinus\u003c/em\u003e (Karny), commonly known as the invasive black flower thrips, has recently emerged as a major threat to chilli (\u003cem\u003eCapsicum spp\u003c/em\u003e.) production in India, causing significant economic losses and posing challenges to sustainable cultivation. Since its first report in India on \u003cem\u003eCarica papaya\u003c/em\u003e in Bengaluru (Tyagi et al., \u003cspan citationid=\"CR45\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), T. \u003cem\u003eparvispinus\u003c/em\u003e has expanded its host range to include several economically important crops such as chilli, beans, eggplant, pepper, potato, shallot, strawberry, and ornamentals like Brugmansia and Dahlia (Rachana et al., \u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e2018\u003c/span\u003e; Roselin et al., \u003cspan citationid=\"CR41\" class=\"CitationRef\"\u003e2021\u003c/span\u003e; NPPO, 2019). This polyphagous pest is predominantly found on white, fragrant flowers where it feeds on pollen, causing characteristic brownish streaks on petals, flower drop, and ultimately, a drastic reduction in fruit yield and quality. Infestation leads to malformed fruits with button-shaped or rugged surfaces, severely impacting marketability (Maharijaya et al., \u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e2011\u003c/span\u003e; Hutasoit et al., \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e2019\u003c/span\u003e).\u003c/p\u003e\u003cp\u003eThe pests biology shows adults exhibiting peak flight activity in the morning, preferring flowers, while nymphs inhabit leaves, complicating management strategies (Pratiwi et al., \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). The complex thrips fauna in chilli ecosystems makes accurate identification and monitoring of \u003cem\u003eT. parvispinus\u003c/em\u003e difficult but essential for effective pest management (Palanisamy et al., \u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e2023\u003c/span\u003e). Biochemical factors, particularly plant secondary metabolites such as phenolics, tannins, and free amino acids, play a pivotal role in host plant resistance by influencing thrips behavior, feeding, and reproduction. Phenolic compounds act as antixenotic agents, deterring thrips feeding and oviposition, while tannins reduce nutrient availability and disrupt insect digestion, thereby limiting pest proliferation (Panda and Khush, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e1995\u003c/span\u003e; Bharathi, \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Pathak and Saxena, 1976). Understanding these biochemical interactions is critical to developing resistant chilli cultivars and integrated pest management (IPM) strategies.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cp\u003e\u003cb\u003eExperimental details\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe study was conducted during summer 2024 at the College of Agriculture, V. C. Farm, Mandya, Karnataka, situated in the Southern Dry Zone (Zone-6). Thirty-two chilli (\u003cem\u003eCapsicum annuum L.\u003c/em\u003e) hybrids, including susceptible checks such as \u0026lsquo;Byadgi Kaddi\u0026rsquo;, were evaluated for response to \u003cem\u003eT. parvispinus\u003c/em\u003e under field conditions. Thirty-day-old seedlings were transplanted in a randomized complete block design with three replications, maintaining 60 cm \u0026times; 45 cm spacing. Standard agronomic practices, including uniform fertilizer application and irrigation, were followed as per University of Agricultural Sciences, Bengaluru recommendations (Anonymous, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cb\u003eAssessment of thrips infestation and biochemical analysis\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThrips infestation and plant response were monitored regularly throughout the crop growth period. Leaf curl index, an indicator of thrips damage, was recorded following Niles (1980). For biochemical analysis, uninfested top leaves were collected at 60 days after transplanting (DAT) during summer 2024 from two representative hybrids per resistance category identified via preliminary screening over two seasons. Twelve hybrids, including susceptible checks such as \u0026lsquo;Byadgi Kaddi\u0026rsquo;, were selected. Samples were analyzed for total sugars, reducing sugars, total phenols, tannins, crude protein, and free amino acids using standard protocols.\u003c/p\u003e\u003cp\u003e\u003cb\u003eBiochemical components and their roles in plant defense and nutrition\u003c/b\u003e\u003c/p\u003e\u003cp\u003eThe biochemical components analyzed in this study play crucial roles in plant defense and nutrition. Total sugars, estimated using the Somogyi (\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e1952\u003c/span\u003e) method, serve as attractants to herbivores and are vital for plant growth and maintaining nutritional balance (Jeandet et al., \u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Reducing sugars, also determined by the Somogyi method, influence the nutritional quality of plants, attract herbivores, and mediate defense responses (Khatri and Chhetri, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e2020\u003c/span\u003e). Total phenols, quantified by the Folin\u0026ndash;Ciocalteau method, function as deterrents and antifeedants that adversely affect insect reproduction and growth (Dai and Mumper, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2010\u003c/span\u003e). Crude protein content, measured by the Micro-Kjeldahl method, contributes to the nutritional profile through amino acid composition and can influence herbivore attraction (Robbins et al., \u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e1987\u003c/span\u003e). Total free amino acids, assessed using the ninhydrin method, play a dual role by attracting natural enemies of pests and mediating plant defensive responses (Baqir et al., \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Lastly, tannins, estimated through the Folin-Denis method, impact herbivore behavior by affecting egg-laying, digestion, and physiology and impart an astringent taste that serves as a feeding deterrent (Hassanpour et al., \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e2011\u003c/span\u003e). Together, these biochemical constituents mediate complex interactions between plants and herbivorous insects and are integral to developing pest-resistant cultivars.\u003c/p\u003e\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003eStatistical analysis\u003c/h2\u003e\u003cp\u003eThe mean data on biochemical and nutritional factors was worked out for each test hybrid representing different resistance categories, and the data was subjected to ANOVA (Gomez and Gomez, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e1984\u003c/span\u003e; Hoshmand, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e1988\u003c/span\u003e) after suitable statistical transmission (Arc sin) and means was separated by Tukey\u0026rsquo;s HSD (Tukey \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1965\u003c/span\u003e) for tabulation and interpretation. Further, the data on per cent leaf curl index (PLI) and plant biochemicals in each test hybrid were subjected to the Multiple Linear Regression analysis technique (MLR) (Panse and Sukhathme,1967) by fitting different functions using the software \u0026ldquo;SAS-Syntex Reference Guide 2016, version 16 (SPS16), South Whacker Drive, Chicago, IL.\u0026rdquo;\u003c/p\u003e\u003c/div\u003e"},{"header":"Results and Discussion","content":"\u003cp\u003eThe studies on various biochemical and nutrient factors associated with the resistance and susceptibility of chilli hybrids against the black thrips were conducted during Summer 2024 and the results are presented here.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTotal Phenols\u003c/strong\u003e\u003cp\u003eTotal phenol content showed a decreasing trend with increased susceptibility of chilli hybrids to \u003cem\u003eThrips parvispinus\u003c/em\u003e, ranging from 3.91 mg g⁻\u0026sup1; in resistant to 1.44 mg g⁻\u0026sup1; in susceptible genotypes (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Resistant hybrids Iravata and Meenakshi recorded the highest phenol levels (3.91 and 3.75 mg g⁻\u0026sup1;), while moderately resistant hybrids Kalavathi and Dolphin had 3.69 and 3.44 mg g⁻\u0026sup1;, respectively. Moderately susceptible hybrids (Rakshak, Praveen, Pithamber) showed intermediate phenol content (2.8\u0026ndash;3.1 mg g⁻\u0026sup1;), and susceptible genotypes such as Akshaya-22 and ARD lines exhibited lower values (2.22\u0026ndash;2.59 mg g⁻\u0026sup1;). The lowest phenol levels were recorded in highly susceptible Kavitha, KGF-2, and susceptible check Byadagi Kaddi (1.44\u0026ndash;1.86 mg g⁻\u0026sup1;). Correlation analysis revealed a strong negative association between total phenols and leaf curl incidence (r = \u0026minus;\u0026thinsp;0.98**, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003cp\u003e\u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e\u003ccaption language=\"En\"\u003e\u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\u003cdiv class=\"CaptionContent\"\u003e\u003cp\u003eBiochemical constituents of chilli hybrids associated with resistance to chilli black thrips, \u003cem\u003eT. parvispinus\u003c/em\u003e at 60 DAT during, \u003cem\u003eSummer\u003c/em\u003e 2024\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"10\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eSl.\u003c/p\u003e\u003cp\u003eNo.\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eCategory\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eHybrids\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003ePLI\u003c/p\u003e\u003cp\u003e(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colspan=\"6\" nameend=\"c10\" namest=\"c5\"\u003e\u003cp\u003eBiochemical components (mg g\u003csup\u003e-1\u003c/sup\u003e)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eTotal \u003c/p\u003e\u003cp\u003ePhenols\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c6\"\u003e\u003cp\u003eTotal soluble \u003c/p\u003e\u003cp\u003esugars\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c7\"\u003e\u003cp\u003eTotal reducing \u003c/p\u003e\u003cp\u003esugars\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c8\"\u003e\u003cp\u003eCrude \u003c/p\u003e\u003cp\u003eproteins\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c9\"\u003e\u003cp\u003eTotal free \u003c/p\u003e\u003cp\u003eamino acid\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c10\"\u003e\u003cp\u003eTannins\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eIravata\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.00 (14.18)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.91\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.84\u003csup\u003en\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.36\u003csup\u003el\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3.88\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e19.97\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e4.23\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eMeenakshi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e6.67 (14.97)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.75\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e2.75\u003csup\u003em\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.46\u003csup\u003ek\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3.26\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e19.57\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e4.17\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e3\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eMR\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eKalavathi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e15.67 (23.32)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.69\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.07\u003csup\u003el\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.55\u003csup\u003ej\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e3.95\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e19.4\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.92\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e4\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eDolphin\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e19.33 (26.08)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.44\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.14\u003csup\u003ek\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.70\u003csup\u003ei\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e5.05\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e18.78\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.87\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e5\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eMS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eRakshak\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e23.67 (29.11)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e3.12\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.76\u003csup\u003ej\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e1.96\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e5.45\u003csup\u003eef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e18.51\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.58\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e6\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePraveen\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e28.00 (31.95)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.96\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e3.92\u003csup\u003ei\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.16\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e5.87\u003csup\u003ede\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e17.92\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.41\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e7\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003ePithamber\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e30.00 (33.21)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.84\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.13\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.36\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6.19\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e17.54\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.26\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e8\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"2\" rowspan=\"3\"\u003e\u003cp\u003eS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eAkshaya-22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e34.33 (35.87)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.59\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.30\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.58\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6.09\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e17.08\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.18\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e9\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eARD-5555\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e38.33 (38.25)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.34\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.67\u003csup\u003ef\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.78\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6.70\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e16.51\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.15\u003csup\u003ehi\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e10\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eARD-499\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e44.33 (41.74)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e2.22\u003csup\u003eg\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e4.86\u003csup\u003ee\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.81\u003csup\u003ed\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e6.38\u003csup\u003ecd\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e16.09\u003csup\u003ei\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e3.12\u003csup\u003ei\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\" morerows=\"1\" rowspan=\"2\"\u003e\u003cp\u003eHS\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eKavitha\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e57.33 (48.64)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.86\u003csup\u003eh\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5.22\u003csup\u003ec\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e2.98\u003csup\u003ebc\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e7.23\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e15.77\u003csup\u003eij\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e2.84\u003csup\u003ek\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e12\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eKGF-2\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e56.67 (48.83)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.69\u003csup\u003ei\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e5.34\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3.01\u003csup\u003eb\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e7.22\u003csup\u003eab\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e15.49\u003csup\u003ej\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e2.52\u003csup\u003el\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c2\"\u003e\u003cp\u003eSC\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c3\"\u003e\u003cp\u003eByadagi kaddi\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e68.87 (56.09)\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.44\u003csup\u003ej\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e6.52\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e3.13\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e7.58\u003csup\u003ea\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e14.17\u003csup\u003ek\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e2.33\u003csup\u003em\u003c/sup\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eSE m \u0026plusmn;\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e2.81\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.03\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.02\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.08\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.04\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.14\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colspan=\"3\" nameend=\"c3\" namest=\"c1\"\u003e\u003cp\u003eCD @ p\u0026thinsp;=\u0026thinsp;0.01\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c4\"\u003e\u003cp\u003e8.54\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c5\"\u003e\u003cp\u003e0.11\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c6\"\u003e\u003cp\u003e0.07\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c7\"\u003e\u003cp\u003e0.26\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c8\"\u003e\u003cp\u003e0.22\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c9\"\u003e\u003cp\u003e0.13\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"left\" colname=\"c10\"\u003e\u003cp\u003e0.40\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003c/tbody\u003e\u003c/colgroup\u003e\u003ctfoot\u003e\u003ctr\u003e\u003ctd colspan=\"10\"\u003eFigures in the parenthesis indicate arcsine transformed values; Values in the column followed by common letters are non-significant at p\u0026thinsp;=\u0026thinsp;0.05 as per Tukey\u0026rsquo;s HSD (Tukey, \u003cspan citationid=\"CR44\" class=\"CitationRef\"\u003e1965\u003c/span\u003e); R- Resistant; MR- Moderately resistant; MS- Moderately MS- Moderately susceptible; S- Susceptible; SC- Susceptible check.\u003c/td\u003e\u003c/tr\u003e\u003c/tfoot\u003e\u003c/table\u003e\u003c/div\u003e\u003c/p\u003e\u003c/p\u003e\u003cp\u003eThese findings corroborate earlier studies in chilli and related crops where phenolic compounds were reported as key antixenotic factors conferring resistance to thrips and other insect pests by Subhash et al. (\u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2013\u003c/span\u003e), Vijaykumar et al. (\u003cspan citationid=\"CR48\" class=\"CitationRef\"\u003e2015a\u003c/span\u003e, \u003cspan citationid=\"CR49\" class=\"CitationRef\"\u003e2015b\u003c/span\u003e, \u003cspan citationid=\"CR50\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), Prasannakumar et al. (\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e2015\u003c/span\u003e), and Jyothi et al. (\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). Phenolics act as feeding deterrents and reduce insect fecundity by interfering with digestion and nutrient assimilation, thus limiting pest population buildup. Similar negative correlations between total phenols and thrips infestation have been reported in \u003cem\u003eScirtothrips dorsalis\u003c/em\u003e on chilli (Chaudhary and Pandya, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e) and other host-pest systems. Therefore, total phenol content serves as a reliable biochemical marker for host plant resistance to \u003cem\u003eT. parvispinus\u003c/em\u003e. Integration of phenolic profiling in chilli breeding programmes could facilitate the development of thrips-resistant cultivars, contributing to sustainable pest management.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTotal soluble sugars (TSS)\u003c/strong\u003e\u003cp\u003eSignificant variation in total soluble sugar (TSS) content was observed among the chilli hybrids, ranging from 2.75 mg g⁻\u0026sup1; in resistant to 6.52 mg g⁻\u0026sup1; in susceptible genotypes (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Resistant hybrids, Iravata and Meenakshi, recorded the lowest TSS levels (2.84 and 2.75 mg g⁻\u0026sup1;, respectively), while moderately resistant hybrids Kalavathi and Dolphin had slightly higher values (3.07 and 3.14 mg g⁻\u0026sup1;). Moderately susceptible hybrids (Rakshak, Praveen, Pithamber) exhibited intermediate TSS content (3.76\u0026ndash;4.13 mg g⁻\u0026sup1;). Susceptible hybrids, including Akshaya-22, ARD-5555, ARD-499, Kavitha, and KGF-2, showed progressively higher TSS levels, with the susceptible check Byadagi Kaddi recording the maximum (6.52 mg g⁻\u0026sup1;). Correlation analysis revealed a strong positive influence of TSS on leaf curl incidence (r\u0026thinsp;=\u0026thinsp;0.98**, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003eThese findings are consistent with previous reports linking higher sugar content to increased thrips infestation in chilli (Rameash et al., \u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e2015\u003c/span\u003e) and other crops (Roopa, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Subhash et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Chaudhary and Pandya, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). Sugars are essential nutrients and energy sources for insects, and their elevated presence may enhance host suitability and act as feeding stimulants, thereby increasing pest attraction and colonization (Mittler and Dadd, \u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e1962\u003c/span\u003e; Corcuera, 1993; Nawalgatti et al., 1999). This positive correlation between total sugar content and susceptibility has been observed across various host-pest interactions, including rice genotypes and different insect pests like gall midge, leaf folder, and brown planthopper (Vijaykumar et al., 2009, 2012; Vanitha et al., \u003cspan citationid=\"CR46\" class=\"CitationRef\"\u003e2015\u003c/span\u003e; Ashrith et al., \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2017\u003c/span\u003e). This supports the theory of co-evolution where lower nutritional quality, in terms of accessible sugars, serves as a chemical defense mechanism against herbivory.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTotal reducing sugars (TRS)\u003c/strong\u003e\u003cp\u003eSignificant variation in total reducing sugar content was observed among the chilli hybrids, ranging from 1.36 to 3.13 mg g⁻\u0026sup1; (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Resistant hybrids Iravata and Meenakshi recorded the lowest reducing sugars of 1.36 and 1.46 mg g⁻\u0026sup1;, respectively, while moderately resistant hybrids Kalavathi and Dolphin exhibited slightly higher values of 1.55 and 1.70 mg g⁻\u0026sup1;. Moderately susceptible hybrids Rakshak, Praveen, and Pithamber showed intermediate levels (1.96\u0026ndash;2.36 mg g⁻\u0026sup1;), whereas susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 ranged from 2.58 to 2.81 mg g⁻\u0026sup1;. Highly susceptible Kavitha and KGF-2 recorded 2.98 and 3.01 mg g⁻\u0026sup1;, respectively, with the susceptible check Byadgi Kaddi having the highest amount of 3.13 mg g⁻\u0026sup1;. Correlation analysis demonstrated a strong positive relationship between total reducing sugars and leaf curl incidence caused by \u003cem\u003eT. parvispinus\u003c/em\u003e at 60 days after transplanting (r\u0026thinsp;=\u0026thinsp;0.95**, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003eThese results concur with findings by Praveen et al. (\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2022\u003c/span\u003e), who reported lower reducing sugar content in resistant chilli germplasm compared to susceptible lines, with the highest reducing sugars recorded in the susceptible check Byadgi Kaddi. Reducing sugars, including oligosaccharides and monosaccharides, serve as essential nutrients for insect pests and act as feeding stimulants due to their sweetness, thereby enhancing pest infestation. Several studies have similarly observed lower reducing sugar levels in resistant germplasm of \u003cem\u003eScirtothrips dorsalis\u003c/em\u003e and documented a positive correlation between reducing sugar content and thrips infestation (Varadharajan and Veeravel, \u003cspan citationid=\"CR47\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Megharaj et al., \u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e2016\u003c/span\u003e; Chaudhary and Pandya, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e; Subhash et al., \u003cspan citationid=\"CR43\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). The present findings thus reinforce the role of reducing sugars as biochemical factors influencing host susceptibility to thrips.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eCrude proteins\u003c/strong\u003e\u003cp\u003eSignificant variation in crude protein content was observed among the chilli hybrids, ranging from 3.26 to 7.58 mg g⁻\u0026sup1; (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Resistant hybrids Iravata and Meenakshi recorded the lowest protein levels of 3.88 and 3.26 mg g⁻\u0026sup1;, respectively, while moderately resistant hybrids Kalavathi and Dolphin showed intermediate values of 3.95 and 5.05 mg g⁻\u0026sup1;. Moderately susceptible hybrids Rakshak, Praveen, and Pithamber exhibited higher protein content (5.45\u0026ndash;6.19 mg g⁻\u0026sup1;), and susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 had even greater amounts (6.09\u0026ndash;6.70 mg g⁻\u0026sup1;). Highly susceptible Kavitha and KGF-2 showed protein concentrations exceeding 7.20 mg g⁻\u0026sup1;, with the susceptible check Byadagi Kaddi registering the highest level of 7.58 mg g⁻\u0026sup1;. Correlation analysis indicated a significant positive relationship between crude protein content and leaf curl incidence caused by Thrips parvispinus (r\u0026thinsp;=\u0026thinsp;0.93**, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003eThese results agree with previous studies reporting lower protein content in resistant chilli germplasm compared to susceptible ones (Praveen et al., \u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). Proteins are vital biomolecules involved in cellular functions and plant defense signaling; changes in protein profiles often represent early responses to insect herbivory (Green and Ryan, \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e1972\u003c/span\u003e; Rafi et al., \u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e1996\u003c/span\u003e; Ni et al., \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e2001\u003c/span\u003e). Increased protein content following insect attack has been noted as a common defense mechanism (Chen et al., 2009). However, higher total protein content has been associated with increased susceptibility to thrips (Alabi et al., 2005; Roopa, \u003cspan citationid=\"CR40\" class=\"CitationRef\"\u003e2013\u003c/span\u003e; Chaudhary and Pandya, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2019\u003c/span\u003e). The positive correlation observed here between protein content and thrips infestation corroborates these findings, underscoring crude protein as a marker of host susceptibility.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTotal free amino acids (TFA)\u003c/strong\u003e\u003cp\u003eTotal free amino acids (TFA) content varied significantly among the selected chilli hybrids, ranging from 14.17 to 19.97 mg g⁻\u0026sup1;, with a decreasing trend correlating with increased susceptibility to \u003cem\u003eT. parvispinus\u003c/em\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Resistant hybrids Iravata and Meenakshi recorded the highest TFA levels (19.97 and 19.57 mg g⁻\u0026sup1;, respectively), statistically comparable to moderately resistant hybrids Kalavathi (19.40 mg g⁻\u0026sup1;) and Dolphin (18.78 mg g⁻\u0026sup1;). Moderately susceptible hybrids such as Rakshak, Praveen, and Pithamber had intermediate TFA contents (17.54\u0026ndash;18.51 mg g⁻\u0026sup1;), while susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 showed reduced levels (16.09\u0026ndash;17.08 mg g⁻\u0026sup1;). Highly susceptible genotypes Kavitha and KGF-2 recorded 15.49 and 15.77 mg g⁻\u0026sup1;, respectively, with the lowest TFA content found in the susceptible check Byadagi Kaddi (14.17 mg g⁻\u0026sup1;). Correlation analysis revealed a strong and significant negative relationship between TFA and leaf curl incidence at 60 days after transplanting (r = \u0026minus;\u0026thinsp;0.98**, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003eFree amino acids serve as essential nutrients that support insect growth, development, and reproduction by participating in protein synthesis and biogenetic pathways (Douglas, 2006). The observed negative correlation may indicate that higher TFA content enhances plant defensive metabolism, possibly through diversion of amino acids into secondary metabolites via pathways such as the phenylpropanoid route, conferring resistance to biotic stresses.\u003c/p\u003e\u003cp\u003eSimilar negative correlations between free amino acid levels and pest incidence have been reported in crops such as rice and sorghum against various pests (Vijaykumar et al., 2012; Pallavi et al., \u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Megha et al., \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e2022\u003c/span\u003e; Punithkumar et al., 2020). This study confirms the critical role of total free amino acids as biochemical markers linked to resistance against thrips in chilli and highlights their potential utility in breeding programs aimed at enhancing pest resistance.\u003c/p\u003e\u003cp\u003e\u003cstrong\u003eTannins\u003c/strong\u003e\u003cp\u003eTannin content varied significantly among chilli hybrids, with resistant genotypes exhibiting higher levels compared to susceptible ones (Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). Resistant hybrids Iravata and Meenakshi recorded the highest tannin concentrations of 4.23 and 4.17 mg g⁻\u0026sup1;, respectively, while moderately resistant hybrids Kalavathi and Dolphin had slightly lower but comparable levels of 3.92 and 3.87 mg g⁻\u0026sup1;. Moderately susceptible hybrids Rakshak, Praveen, and Pithamber contained tannin amounts ranging from 3.26 to 3.58 mg g⁻\u0026sup1;. In contrast, susceptible hybrids Akshaya-22, ARD-5555, and ARD-499 exhibited significantly reduced tannin content (~\u0026thinsp;3.15 mg g⁻\u0026sup1;). Highly susceptible genotypes Kavitha and KGF-2 showed further decreased tannins (2.52\u0026ndash;2.84 mg g⁻\u0026sup1;), with the susceptible check Byadagi Kaddi having the lowest level (2.33 mg g⁻\u0026sup1;). Correlation analysis revealed a strong negative association between tannin content and leaf curl incidence at 60 days after transplanting (r = \u0026minus;\u0026thinsp;0.97**, Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\u003c/p\u003e\u003cp\u003eTannins are known to exert deleterious effects on phytophagous insects by binding to dietary proteins, reducing nutrient absorption, and causing midgut lesions that impair insect growth and development (Dubey et al., \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2016\u003c/span\u003e). These polyphenolic compounds possess astringent and bitter properties that act as feeding deterrents. Mechanistically, tannins precipitate proteins, including digestive enzymes of herbivores, via hydrogen or covalent bonds with \u0026ndash;NH₂ groups, and also chelate essential metal ions, thereby decreasing their bioavailability to pests. Consequently, tannins diminish protein digestibility and the nutritive value of plant tissues, contributing to antixenosis and resistance against thrips infestation.\u003c/p\u003e\u003cp\u003eThe present study elucidates the critical role of biochemical and nutritional factors in conferring resistance against \u003cem\u003eThrips parvispinus\u003c/em\u003e in chilli hybrids. Resistant genotypes were characterized by elevated levels of defensive metabolites\u0026mdash;total phenols, tannins, and free amino acids\u0026mdash;coupled with reduced concentrations of total soluble sugars, reducing sugars, and crude proteins. Strong and significant correlations between these biochemical constituents and thrips infestation underscore their involvement in host plant resistance. Particularly, phenolic compounds demonstrated potent antixenotic effects, positioning them as reliable biochemical markers for resistance breeding. These findings provide a robust foundation for exploiting such traits through conventional breeding and biotechnological interventions to develop thrips-resistant cultivars. Integrating these biochemical parameters into selection criteria promises a sustainable, eco-friendly strategy for thrips management, reducing reliance on chemical pesticides. Further studies are warranted to dissect the molecular mechanisms underlying these resistance traits and to validate their stability and efficacy under diverse agro-climatic conditions, thereby facilitating their adoption in chilli improvement programs.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eFinancial Support\u003c/strong\u003e\u003cp\u003eNo funding received.\u003c/p\u003e\u003c/p\u003e\u003cp\u003e\u003ch2\u003eConflict Of Interest\u003c/h2\u003e\u003cp\u003eThe authors declare that they have no financial or non-financial conflict of interest.\u003c/p\u003e\u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eGaurav Vinod Rao Sadafale - Conceptualization, investigation, draft preparation and analysis; L. Vijaykumar - Conceptualization, framed research proposal and draft correction; N Kiran Kumar, G. Somu, Shivaray Navi and Nagesh Malasiddappa Chikkarugi- Writing, reviewing and editing of research article. All authors read and approved the manuscript.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e\u003cp\u003eThe authors are thankful to the authorities of University of Agricultural Sciences, Bangalore. The thanks are also due to the Dean (PGS), Directorate of Post Graduate studies and Director of Research, University of Agricultural Sciences, Bangalore.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eAlabi OY, Odebiyi JA, Tamo M (2006) The relationship between primary metabolites in reproductive structures of cowpea \u003cem\u003eVigna unguiculata\u003c/em\u003e (Fabaceae: Papilionidae) cultivars and field resistance to the flower bud thrips, \u003cem\u003eMegalurothrips sjostedti\u003c/em\u003e (Thysanoptera: Thripidae). Int J Trop Insect Sci 26(1):8\u0026ndash;15. https://doi.org/10.1079/IJT2006112\u003c/li\u003e\n\u003cli\u003eAnonymous (2022) Package of practices for sugarcane cultivation. 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Mol Biol Rep 50(12):9909\u0026ndash;9923. https://doi.org/10.1007/s11033-023-08673-4\u003c/li\u003e\n\u003cli\u003ePallavi D, Vijaykumar L, Shivanna M, Prasannakumar MK, Madhusudan K (2022) Biochemical basis of resistance to sesame phyllody transmitted by leafhopper in sesame. Int J Curr Microbiol Appl Sci 11(11):1\u0026ndash;9\u003c/li\u003e\n\u003cli\u003ePanda N, Khush GS (1995) Host-plant resistance to insects. Int Rice Res Inst, Manila, Philippines, CAB International, pp 31\u0026ndash;53\u003c/li\u003e\n\u003cli\u003ePanse VG, Sukhatme PV (1967) Statistical methods for agricultural workers. ICAR Publication, IARI, New Delhi, pp 359\u003c/li\u003e\n\u003cli\u003ePathak M, Saxena R (2013) Insect resistance in crop plants. Comment Plant Sci 2:61\u003c/li\u003e\n\u003cli\u003ePrasannakumar NR, Chander S, Vijay Kumar L (2015) Development of weather-based rice yellow stem borer prediction model for the Cauvery command rice areas, Karnataka, India. Cogent Food Agric 1:995281. https://doi.org/10.1080/23311932.2015.995281\u003c/li\u003e\n\u003cli\u003ePratiwi NPE, Supartha IW, Yuliadhi KA (2018) Aktivitas penerbangan dan perkembangan populasi \u003cem\u003eThrips parvispinus\u003c/em\u003e Karny (Thysanoptera: Thripidae) pada tanaman cabai besar (\u003cem\u003eCapsicum annuum\u003c/em\u003e L.). Agrotrop 8(1):29\u0026ndash;37\u003c/li\u003e\n\u003cli\u003ePraveen SL, Mohapatra LN, Naresh P, Sahu GS (2022) The activity of defensive enzymes in chilli germplasm in relation to their reaction to chilli thrips, \u003cem\u003eScirtothrips dorsalis\u003c/em\u003e (Hood). Pest Manag Horticult Ecosyst 28(1):64\u0026ndash;69\u003c/li\u003e\n\u003cli\u003ePuneeth Kumar KJ, Kumar LV, Raveendra HR, Sanath VB (2020) Biochemical mechanism of resistance to shoot fly, \u003cem\u003eAtherigona approximata\u003c/em\u003e Malloch in foxtail millet (\u003cem\u003eSetaria italica\u003c/em\u003e L.). J Entomol Zool Stud 8(6):223\u0026ndash;227\u003c/li\u003e\n\u003cli\u003eRachana RR, Roselin P, Varatharajan R (2018) Report of invasive thrips species, \u003cem\u003eThrips parvispinus\u003c/em\u003e (Karny) (Thripidae: Thysanoptera) on \u003cem\u003eDahlia rosea\u003c/em\u003e (Asteraceae) in Karnataka. Pest Manag Horticult Ecosyst 24(2):187\u0026ndash;188\u003c/li\u003e\n\u003cli\u003eRafi MM, Zemetra RS, Quisenberry SS (1996) Interaction between Russian wheat aphid (Homoptera: Aphididae) and resistant and susceptible genotypes of wheat. J Econ Entomol 89(1):239\u0026ndash;246. https://doi.org/10.1093/jee/89.1.239\u003c/li\u003e\n\u003cli\u003eRameash K, Pandravada SR, Sivaraj N, Pranusha P, Sarathbabu B, Chakrabarty SK (2015) Agro-morphological traits of resistance in chilli against thrips, \u003cem\u003eScirtothrips dorsalis\u003c/em\u003e and analysing the geographic divergence of resistance. Community Environ Assess 9(3-4):841\u0026ndash;848\u003c/li\u003e\n\u003cli\u003eRobbins CT, Hanley TA, Hagerman AE, Hjeljord O, Baker DL, Schwartz CC, Mautz WW (1987) Role of tannins in defending plants against ruminants: reduction in protein availability. Ecology 68(1):98\u0026ndash;107. https://doi.org/10.2307/1938374\u003c/li\u003e\n\u003cli\u003eRoopa HR (2013) Studies on biochemical resistance in chilli against thrips (\u003cem\u003eScirtothrips dorsalis\u003c/em\u003e Hood). M.Sc. thesis, Univ Agric Sci, Bangalore, India\u003c/li\u003e\n\u003cli\u003eRoselin K, Praveen P, Varatharajan K (2021) Status of invasive thrips, \u003cem\u003eThrips parvispinus\u003c/em\u003e Karny on chilli and its management strategies. J Trop Agric 59(2):89\u0026ndash;96\u003c/li\u003e\n\u003cli\u003eSomogyi M (1952) Estimation of sugars by colorimetric method. J Biol Chem 200(245):89\u0026ndash;111\u003c/li\u003e\n\u003cli\u003eSubhash BK, Khader KH, Chakravarth AK, Ashok Kumar CT, Venkataravana P (2013) Biochemical constituents influencing thrips resistance in groundnut germplasm. J Environ Biol 35:675\u0026ndash;681\u003c/li\u003e\n\u003cli\u003eTukey JW (1965) The technical tools of statistics. Am Stat 19(2):23\u0026ndash;28. https://doi.org/10.1080/00031305.1965.10480929\u003c/li\u003e\n\u003cli\u003eTyagi K, Kumar V, Singha D, Chakraborty R (2015) Morphological and DNA barcoding evidence for invasive pest thrips, \u003cem\u003eThrips parvispinus\u003c/em\u003e (Thripidae: Thysanoptera), newly recorded from India. J Insect Sci 15(1):105. https://doi.org/10.1093/jisesa/iev086\u003c/li\u003e\n\u003cli\u003eVanitha BK, Kumar CTA, Kumar LV, Prashantha C (2015) Association of biochemical factors in rice against infestation of rice leaf folder, \u003cem\u003eCnaphalocrocis medinalis\u003c/em\u003e (Guenee) (Lepidoptera: Pyralidae). J Exp Zool 18(1):373\u0026ndash;376\u003c/li\u003e\n\u003cli\u003eVaradharajan S, Veeravel R (1996) Evaluation of chilli accessions resistant to thrips, \u003cem\u003eScirtothrips dorsalis\u003c/em\u003e Hood (Thysanoptera: Thripidae). Pest Manag Econ Zool 4(1-2):85\u0026ndash;90\u003c/li\u003e\n\u003cli\u003eVijaykumar L, Chakravarthy AK, Patil SU (2015a) Antixenosis and antibiosis component of rice resistance to Asian rice gall midge, \u003cem\u003eOrseolia oryzae\u003c/em\u003e (Wood-Mason). In: New Horizons in Insect Science. Springer, pp 269\u0026ndash;276. https://doi.org/10.1007/978-81-322-2089-3_24\u003c/li\u003e\n\u003cli\u003eVijaykumar L, Chakravarthy AK, Patil SU (2015b) Impact of gall midge, \u003cem\u003eOrseolia oryzae\u003c/em\u003e (Wood-Mason) infestation on total phenols, proline and indole acetic acid in paddy (\u003cem\u003eOryza sativa\u003c/em\u003e Linn.) genotypes. In: New Horizons in Insect Science. Springer, pp 261\u0026ndash;267. https://doi.org/10.1007/978-81-322-2089-3_23\u003c/li\u003e\n\u003cli\u003eVijaykumar L, Patil SU, Shivanna B, Kitturmath MS (2022) Hypersensitive response and induced resistance in rice gene differentials against biotype 1 of Asian rice gall midge, \u003cem\u003eOrseolia oryzae\u003c/em\u003e at Mandya, Karnataka. J Rice Res Dev 15(1):70\u0026ndash;76\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"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":"Thrips parvispinus, Chilli, Host plant resistance, Pest infestation dynamics, Biochemical components","lastPublishedDoi":"10.21203/rs.3.rs-7151468/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7151468/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cem\u003eThrips parvispinus\u003c/em\u003e (Karny) (Thysanoptera: Thripidae) is a recently invasive and highly polyphagous pest species causing significant damage to chilli (\u003cem\u003eCapsicum spp\u003c/em\u003e.) and other economically important crops in India and worldwide. Despite its quarantine significance, limited studies exist on the biochemical factors influencing its infestation dynamics on different chilli hybrids. This study was conducted during \u003cem\u003eSummer\u003c/em\u003e 2024 at the College of Agriculture, V. C. Farm, Mandya, Karnataka, India, to assess the biochemical traits of chilli leaves that affect \u003cem\u003eT. parvispinus\u003c/em\u003e infestation under field conditions. Biochemical profiling at 60 days after transplanting (DAT) revealed that infestation levels were positively correlated with soluble sugars, reducing sugars, and crude protein content, indicating that nutrient-rich tissues favor thrips population growth. Conversely, defensive phytochemicals such as total phenols, free amino acids, and tannins showed strong negative correlations with thrips infestation, suggesting their role in host resistance by deterring feeding and reproduction. These findings provide valuable insights into the biochemical basis of host susceptibility and resistance, informing the development of chilli hybrids with enhanced defensive traits and integrated pest management strategies to mitigate the impact of \u003cem\u003eT. parvispinus\u003c/em\u003e on chilli production.\u003c/p\u003e","manuscriptTitle":"Investigation of host plant resistance mechanisms in chilli against black thrips, Thrips parvispinus (Karny)","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-08-12 07:17:56","doi":"10.21203/rs.3.rs-7151468/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"decision","content":"Revision requested","date":"2025-08-12T17:25:06+00:00","index":"","fulltext":""},{"type":"reviewerAgreed","content":"237741243462261723765110090546077967287","date":"2025-08-12T11:42:17+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-12T04:19:39+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"125692437400444887107851120133741086124","date":"2025-08-12T03:56:35+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"230359583639270292602214625367396754017","date":"2025-08-09T15:11:16+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"140504086756967691252602941182313125794","date":"2025-08-07T10:31:36+00:00","index":"hide","fulltext":""},{"type":"editorInvitedReview","content":"","date":"2025-08-07T06:56:47+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"240198879890740011612058644443837972967","date":"2025-08-07T05:38:28+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"123027961638371338956352539526592502526","date":"2025-08-07T04:50:23+00:00","index":"hide","fulltext":""},{"type":"reviewerAgreed","content":"289449636066827568124878566733059752665","date":"2025-08-07T01:09:04+00:00","index":"hide","fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-08-06T17:49:13+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-07-18T13:14:57+00:00","index":"","fulltext":""},{"type":"checksComplete","content":"","date":"2025-07-18T13:13:54+00:00","index":"","fulltext":""},{"type":"submitted","content":"International Journal of Tropical Insect Science","date":"2025-07-17T17:38:12+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":"d2d926f9-1820-48c4-a391-bdbb433a5c6a","owner":[],"postedDate":"August 12th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2025-11-10T16:04:22+00:00","versionOfRecord":{"articleIdentity":"rs-7151468","link":"https://doi.org/10.1007/s42690-025-01624-2","journal":{"identity":"international-journal-of-tropical-insect-science","isVorOnly":false,"title":"International Journal of Tropical Insect Science"},"publishedOn":"2025-11-07 15:56:54","publishedOnDateReadable":"November 7th, 2025"},"versionCreatedAt":"2025-08-12 07:17:56","video":"","vorDoi":"10.1007/s42690-025-01624-2","vorDoiUrl":"https://doi.org/10.1007/s42690-025-01624-2","workflowStages":[]},"version":"v1","identity":"rs-7151468","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-7151468","identity":"rs-7151468","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}