Organic products selectivity for Trichogramma pretiosum (Hymenoptera: Trichogrammatidae)

Abstract

The selectivity of different insecticides, fungicides and fertilizers used in organic soybean cropping was evaluated according to the protocols proposed by the Pesticides and Beneficial Organisms Working Group of the International Organization for Biological Control (IOBC) concerning adults and pupae of the egg parasitoid Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae) under laboratory conditions. Treatments 1) baculovirus anticarsia 140 x 109 cpi; 2) Bacillus thuringiensis 16.8 g; 3) azadirachtin-A, azadirachtin-B, nimbina and salamina 9.6 ppm; 4) rotenoids 4% 4 L; 5) nitrogen 1.3%, phosphorus 3.0% and total organic carbon 8.0% 3 L; 6) sodium silicate 2% 4 L; 7) copper 7% + calcium 3.3% 1.8 L; 8) sulfur 20% + quicklime 10% 1.8 L were in general safe (class 1) to both adults and pupae of T. pretiosum . Differently, chlorpyrifos (control treatment) was harmful to this parasitoid. Therefore, the utilization of the tested natural derived products in the production of organic soybean is viable, without impairing the natural biological control allowed by T. pretiosum . Furthermore, both management techniques can indeed be used together in organic cropping aiming at reaching increasing or complementary control of target pests. Chlorpyrifos use, on the other hand, whenever possible, should be replaced by other products more compatible with biological control preservation.