Desempenho do parasitóide Cotesia flavipes (Cam.) (Hymenoptera : Braconidae) sobre Diatraea saccharalis (Fabr.) e Diatrea flavipennella (Box) (Lepidoptera : Crambidae)

Abstract

This complex of sugarcane borers, in Brazil, comprises Diatraea saccharalis (Fabr.) and Diatraea flavipennella (Box) (Lepidoptera.: Crambidae). The control of borers, in Brazil, is the applied biological control using the larval endoparasitoid Cotesia flavipes (Cam.) (Hymenoptera: Braconidae). Recently, however, the biological control of D. flavipennella by the C. flavipes has been in discussion due to increasing occurrence of this borer species in the sugarcane fields across the northeast of Brazil. Thus, this study investigated the parasitism behavior of the parasitoid C. flavipes towards D. flavipennella side by side to D. saccharalis as well as determined its fertility life table parasitizing both hosts to clearify about this question. The parasitism behavior included free choice and host finding tests with and without visual cues, using arena in the laboratory. Larvae of D. saccharalis and D. flavipennella were exposed to 24h-old C. flavipes females, mated and fed. The free choice test consisted of an arena containing larvae of both sugarcane borers andcontrasted parasitoid wasp emerged from each one. The host finding test was conducted in an arena designed to not allow visual cues to the wasps. The parasitoid wasp in both tests showed no parasitism preference toward a sugarcane borer species being able to find and parasitize both borers similarly. The fertility life table parameters for C. flavipes parasitizing D. saccharalis andD. flavipennella were estimated based on the development and the specific daily parasitism obtained in the laboratory. The results show that C. flavipes exhibited similar parasitism and fertility on both borers, but with longer mean generation time and lower cocoon viability parasitizing D. flavipennella. Based on the results of the parasitism behavior and fertility life tablewe conclude that the parasitism of C. flavipes on D. flavipennella was not compromised.