Toxicidade de inseticidas registrados para uso em cana-de-açúcar ao parasitoide >i<Trichogramma galloi >/i<(Hymenoptera: Trichogrammatidae)

Abstract

Toxicity of insecticides registred for use in sugar cane to parasitoid Trichogramma galloi (Hymenoptera: Trichogrammatidae) The egg parasitoid Trichogramma galloi (Zucchi) is one of the biological control agents of the sugarcane borer, Diatraea saccharalis (Fabricius). However, the intensive use of synthetic insecticides is one of the factors that affect the action of these natural enemies in pest control. The aim of the present study was to evaluate the lethal and transgenerational effects, and persistence of the main insecticides used to control D. saccharalis in sugarcane, at the highest field concentrations for the crop and following IOBC / WPRS standards. It was performed evaluations on adults, larvae and pupae stages of the parasitoid. Chlorantraniliprole, triflumuron, tebufenozide and novaluron were harmless to adults under laboratory conditions. Lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam prevented the parasitism of the host eggs for both insecticides. The insecticide triflumuron was slightly harmful, while fipronil was moderately harmful to the larvae stage. Lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam were harmful to the pupae stage preventing them from emerging. In a semi-field conditions lambda-cyhalothrin + chlorantraniliprole and lambda-cyhalothrin + thiamethoxam insecticides were considered moderately persistent, while fipronil was persistent. Therefore, taking into account an effective IPM program as a target, it is recommended the use of selective insecticides. Pointing out the importance of insect growth regulators, such as tebufenozide and novaluron, and diamides, as chlorantraniliprole, in sugarcane crop areas, as showed in this study.