Nicosulfuron Plus Atrazine Herbicides and Trichogrammatidae (Hymenoptera) in No-Choice Test: Selectivity and Hormesis.

The aim of this study was to evaluate the effect of the herbicide mixture nicosulfuron + atrazine on 10 trichogrammatid species. A female of each trichogrammatid was placed in a test tube (no-choice) with a card with 45 Anagasta kuehniella eggs. Parasitism was allowed over a 48 h period, then the cards were sprayed with a solution containing nicosulfuron (30 g ha-1 ) + atrazine (1500 g ha-1 ), besides the control (distilled water). The nicosulfuron + atrazine mixture increased the Trichogramma atopovirilia and T. pretiosum female emergence. The percentage of T. acacioi, T. atopovilia and T. pretiosum male parasitoids emerged was higher in the control, and for T. demoraesi and Trichogrammatoidea annulata with nicosulfuron + atrazine. Sex ratio of the trichogrammatids was similar with nicosulfuron + atrazine.