Avaliação toxicológica de produtos fitossanitários utilizados na cultura da cana-de-açúcar a Trichogramma galloi Zucchi, 1988 (Hymenoptera: Trichogrammatidae)

Abstract

We aimed at evaluating the effects of the products spinosad, thiamethoxam, fipronil, diuron + hexazinone, trinexapac ethyl, Metarhizium anisopliae and sulfometuron methyl applied to Anagasta kuehniella (Zeller) eggs, affected by Trichogramma galloi Zucchi. A. kuehniella eggs exposed to and affected by the microhymenopteran were treated with the compounds, evaluating the effects in the immature phases over hatching percentages, parasitism capacity, sexual ratio and longevity of the F1 generation females, and over the hatching percentages and sexual ratio in the F2 generation. The compounds in the commercial formulations and in concentrations larger than those recommended for pest control in sugar cane were diluted in water and applied via Potter tower to a card containing affected eggs. The biotrials were conducted at 24 ±1 oC, RH of 70 ± 10% and photophase of 12 hours. Products diuron + hexazinone, trinexapac ethyl, M. anizopliae and sulfometuron methyl showed to be selective to T. galloi. Spinosade, thiamethoxam and fipronil negatively affected T. galloi (F1) hatching when applied over affected eggs, and reduced parasitism rate (F1) and the hatching in generation F2, independent of the immature development phase to which they were applied. Thiamethoxam negatively affected the sexual ratio in T. galloiF1 generation.Spinosade caused the reduction of the average lethal time (LT50), presenting a value of 1.07 days. In regard to the low toxicity presented to T. galloi, diuron + hexazinone, trinexapac ethyl, M. anisopliae and sulfometuron methyl may be used in sugar cane culture, associated to this natural enemy.