Bioatividade de extratos de plantas nativas do cerrado sobre Plutella xylostella (Linnaeus, 1758) (Lepidoptera: plutellidae)

Abstract

Plutella xylostella is considered the main damage agent of brassica, and already it offers a great number of synthetic insecticides, being the use of vegetal extracts a viable alternative for its control. The advantages of using plant extracts are rapid degradation, rapid action, low to moderate toxicity to man, selectivity, low phytoxicity and low cost. The objective of this study was to evaluate the action of aqueous and ethanol extracts from Annona crassiflora, Annona coriacea, Schinus terebinthifolius and Serjania marginata on a food preference, a preference for oviposition, development and reproduction of Plutella xylostella. For the use of aqueous plant extracts (10 g / L) and ethanolic extract (5 mg / mL) were offered to newly hatched caterpillars. As leaves of the control were treated with distilled water. The adult phase of P. xylostella was evaluated as biological characteristics of the juvenile phase. For the food preference experiment, cabbage discs treated with aqueous extracts (5 and 10 g / L) and ethanolic (1 and 5 mg / mL) of the plants in question were offered to third instar caterpillars, between the extract and the witness (water). For the oviposition preference experiment, leaf discs treated with aqueous extracts (5 and 10 g / L) and ethanolic (1 and 5 mg / mL) of plants were inserted in the cage, containing 3 couples of moths, for testes with a chance of choice. Afterwards, the number of eggs in each treatment was evaluated. The results obtained from the food preference tests showed that the aqueous and ethanolic extracts of A. crassiflora and S. terebinthifolius are more effective as antifood on P. xylostella third instar caterpillars. Regarding oviposition preference, the aqueous and ethanol extracts of S. marginata were more effective as the oviposition supply of P. xylostella adults. In the life cycle testes, the aqueous and ethanol extracts from all the plants tested altered at least the standard of the active biological parameters.