Toxicidade de produtos fitossanitários utilizados na cultura da cana-de-açúcar para Trichogramma galloi (Hymenoptera: Trichogrammatidae)

Abstract

The objective of this study was to evaluate the effects of some pesticides (c.p./L) lambda-cyhalothrin/thiamethoxam (0.75) and (12.5); thiamethoxam (13.2); fipronil (0.4); triflumuron (0.25) e spinosad (0.25), used in sugarcane crop to immature phase of Trichogramma galloi (Zucchi). Eggs of Anagasta kuehniella (Zeller) was offered to female of T. galloi by 24h, and then, the pesticides were sprayed by using a Potter's tower containing the parasitoid immature stages (egg-larvae, pre-pupae and pupae). The effects of these pesticides on the emergence, sex ratio, parasitism capacity and F1 female survival were evaluated. To the F2 individuals, only emergence and sex ratio was evaluated. The bioassay was carried out under controlled conditions (climatic chamber) at 25±2ºC, RH 70±10% with a 12 h-photophase. Regardless of the dosage, lambda-cyhalothrin/thiamethoxam and fipronil reduced the percentage of emergency at least on one of immature stages of F1 T. galloi. The sex ratio decreased when T. galloi was exposed to all dosage of lambda-cyhalothrin/thiamethoxam. The biological trait of the period of egg-larvae and pre-pupae of T. galloi was not affected buy triflumuron and spinosad. All pesticides affected the pupae stage, decreasing its sex ratio. Lambda-cyhalothrin/thiamethoxam, thiamethoxam and spinosad reduced the number of parasitized eggs per female of the F1 treated during egg-larva; however, for the pre-pupa, only triflumuron was selective, and the pupal stage all compounds were categorized as slightly harmful. Triflumuron was harmless to T. galloi immature phases, enabling its use in integrated management programs of Diatraea saccharalis (Fabricius) in the crop of sugarcane.