Efeitos do pólen de algodão Bt (Cry1Ac + cry1f) em algumas características biológicas de Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae)

Abstract

Trichogramma is part of a complex of natural enemies used in an integrated pest management program. With the advancement of biotechnology and the use of genetically modified plants with genes from the bacterium Bacillus thurigiensis (Bt), it makes the transgenic plants have a great notoriety in the world agricultural scene. The general objective of this work was to evaluate the effect of Bt cotton pollen on the biological characteristics of adult females of Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae) compared to non-Bt cotton pollen. For this, the following work was developed: Biological characteristics of T. pretiosum fed with cotton pollen. Three treatments (diets) were used: conventional cotton pollen (20 mg of pollen dissolved in 10% honey solution), transgenic cotton pollen (20 mg of pollen dissolved in 10% honey solution) and pure honey solution (control). Each of the diets was used as a feed source for 30 newly emerged and mated females (between 24 and 36 h of age), individualized in eppendorf type microtubes (4,5 cm) containing a (4.5 x 0, 9 cm) with 40 eggs of E. kuehniella. Parasitism was allowed for 24 hours. The experimental design was randomized with 30 replicates with three treatments. Each repetition consisted of an individualized T. pretiosum female. The parasitism presented a difference when fed with Bt pollen having a low percentage of parasitism in the second generation. In the viability of parasitism, treatment with conventional pollen showed a significant difference. On the number of individuals per egg, the third (1.20) and fourth (0.62) generation when fed with Bt pollen. In sex ratio, the third generation obtained the highest value (0.96), thus differing from the others. The third and fourth generation females had a longer longevity when fed with honey. Intake of Bt pollen via diet did not significantly influence the biological characteristics of the parasitoid Trichogramma pretiosum analyzed by four generations.