Comparison between the releasing of different amounts of pupae and adults of Trichogramma pretiosum in lepidopteran eggs control in soybean

This study aimed to assess the amount of released parasitoid pupae and adults of Trichogramma pretiosum in lepidopteran eggs control in soybean. The experiment was carried out in Ribeirão Preto in transgenic RR soybean. The experimental design was randomized blocks, where six treatments were replicated 4 times in 3600 m2 plots, namely: (i) releasing of the equivalent of 100,000 ha1 adult for three consecutive weeks; (ii) 150,000 adults; (iii) 100,000 pupae scattered on the ground, in three consecutive weeks; (iv) 150,000 pupae; (v) chemical control (the conventional to farmers); (vi) control. The parasitoids were released in 12, 19 and 26/12/2014. It was periodically performed two cloth beats (2 linear meters) per share for the caterpillars counting. It was evaluated 10 consecutive plants at the harvest, being counted and weighed the beans. Caterpillars population levels were low (less than two per meter). There was no significant difference (Tukey 5%) between the releasing of pupae and adults of T. pretiosum in Anticarsia gemmatalis, Chrysodeixis includens and Spodoptera spp control. Chemical control was the treatment with the highest average number of caterpillars of the first two species and the lowest number for Spodoptera spp. by 2 linear meters on a few dates. There was no significant difference between treatments in productivity.