Tradescantia pallida (Commelinaceae) Promotes Reductions in Plutella xylostella (Lepidoptera: Plutellidae) Populations

The feeding activity of Plutella xylostella in brassica crops can lead to large losses; thus, pesticides that prevent feeding during the larval stage or prevent the metamorphosis of this insect can be used for its control. In this study, the effects of two types of aqueous extracts of Tradescantia pallida on the different life stage of P. xylostella cycle were tested; neither of the two aqueous extracts, which were obtained by infusion and maceration, had been tested against P. xylostella. The biological variables evaluated were larval and pupal duration and viability, pupal weight, sex ratio, longevity of females, fecundity, fertility and oviposition period. There was no significant difference in the duration of the larval phase of P. xylostella between the bioassay treatments; however, larval viability was lower when the individuals were exposed to both types of T. pallida extracts. Reduced pupal viability was observed among the individuals treated with the application of the extracts. Treatment with the aqueous extract obtained by infusion caused the lowest pupal weight, fecundity, and fertility and longevity among females. The results obtained in this study allow us to propose the bioextract as an alternative for pest management, emphasizing the technique for small producers and/or organic.