Aqueous Extracts of Species of the Genus Campomanesia (Myrtaceae) Affect Biological Characteristics of Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae)

摘要

Plutella xylostella (Linnaeus, 1758) (Lepidoptera: Plutellidae) is an insect pest that causes great damage to Brassica cultures. It is necessary to develop alternative control methods, because this pest is resistant to many synthetic insecticides that are harmful to the environment. The objective of this study was to evaluate the effects of aqueous extracts of Campomanesia adamantium, C. guazumifolia, and C. xanthocarpa on the life cycle of P. xylostella. These aqueous extracts were prepared in a concentration of 10 g/mL and then applied on cabbage disks of 4 cm2 to feed the larvae until they reached pupal stage. The disks were evaluated daily during the larval stage and replaced every 24 hours. The experiment consisted of ten replicates, each replicate containing five subsamples. The parameters evaluated were larval and pupal survival, pupal biomass, gender ratio, male and female longevity, number of eggs, fecundity, oviposition period and egg survival. The C. xanthocarpa extract increased larval stage and decreased pupal biomass and oviposition period. The C. adamantium extract decreased larval duration, pupal biomass, male longevity, and oviposition period. The C. guazumifolia extract decreased larval stage, male longevity, and oviposition period. The chemical composition of the extracts of Campomanesia species presented flavonoids such as quercetin, phenolic compounds, and tannins, and the highest retention time occurred in C. adamantium. Thus, the extracts of Campomanesia species were effective in decreasing and controlling the oviposition period of P. xylostella, probably because of the presence of flavonoids, which indicates a possible antioxidant potential and, therefore, the observed antibiosis.