Bioinsecticidal effect of lantana camara and urtica dioïca grown in northeast Algeria against plodia interpunctella (lepidopterae; pyralidae)

Abstract To valorize both medicinal and aromatic Algerian flora, the present study was performed to assess the effective bio-insecticidal effect of essential oils extracted from the leaves of two aromatic and medicinal plants; L. camara, and U. dioica grown in northeast Algeria, on the development and the reproduction of Plodia interpunctella (Lepidopterae; pyralidae) found in the stored foodstuffs. The yield, organoleptic properties, and toxicity of essential oils were determined. The effectiveness of essential oils was examined using the median lethal concentration (LC50) and 90% lethal concentration (LC90) on some reproductive parameters of adult females of P. interpunctella aged between 0 and 24 hours. The crushed leaves were administered separately to adult insects via ingestion route at increasing doses to estimate the mortality rate for 24, 48, 72, and 96 hours. L. camara extracts were found to have a higher level of essential oils (1.78%) than that of U. dioica (0.95%). In addition, the essential oils of U. dioica and L. camara revealed a significant insecticidal activity with a mortality rate of 84.44±5.09% (U. dioica) and 72.22±6.94% (L. camara). The lethal doses (LC50; LC90) for U. dioica and L. camara were respectively, 5µL/insect; 33µL/insect, and 9.12 µL/insect; 16.94µL/insect. The reproductive effects of essential oils of U. dioica were evidenced by the extended duration of nymphal development and the preoviposition period since those of L. camara were shown by an extension of the preoviposition period, a reduction of the oviposition rate and the duration of nymphal development. Further, results showed a marked decrease in the fertility and viability of the eggs laid by females, resulting in a reduction in reproductive efficiency. The analysis of the leaf powders revealed a potential insecticidal effect proved by an increased mortality rate up to 100% at 72 and 96 hours of exposure. Essential oils and powders of U. dioica and L. camara exhibited considerable bio-insecticide properties against P. interpunctella, and hence they are promised as effective alternatives to synthetic pesticides during the conservation of stored foodstuffs.