Abstract

The aim of this study was to evaluate the effects of fungicides registered for soybean on the parasitoid Trichogramma pretiosum Riley, 1879 (Hymenoptera: Trichogrammatidae). Bioassays wereconducted in laboratory exposing adult insects to dried residues of fungicides, using the methodology proposed by the International Organization for Biological and Integrated Control of Noxious Animals and Plants (IOBC). The experimental design was completely randomized with four replications per treatment. The parameter used for classification of fungicides was based on the reduced parasitism (RP) evidenced by the number of parasitized eggs per female in the control treatment. Based on these results, we found that fungicides are classified in different classes of selectivity to adults of T. pretiosum regarding the tested fungicides. The fungicides cyproconazole, epoxyconazole + kresoxim-methyl, metconazole, thiophanatemethyl (CS), pyraclostrobin, difenoconazole, were classified as harmless (Class 1); carbendazim, carbendazim + thiram, tetraconazole, tetraconazole+ azoxystrobin, epoxyconazol + pyraclostrobin, tebuconazole, prothioconazole + trifloxystrobin, tebuconazole + trifloxystrobin, azoxystrobin, azoxystrobin + cyproconazole, and thiophanate methyl (WG) were slightly harmful (Class 2); flutriafol, thiophanate methyl (WP), epoxyconazole + pyraclostrobin, and cyproconazole+ trifloxystrobin were moderately harmful (Class 3); and Kumulus DF was harmful (Class 4) to the adult parasitoids.

Keywords: Chemical control, integrated pest management (IPM), parasitoid eggs, pesticide, International Organization for biological and integrated control of noxious animals and plants (IOBC) methodology, soybean.