Effects of insecticides and phytoinsecticides on the egg parasitoid Telenomus podisi ashmead (hymenoptera: platygastridae)

The brown stink bug Euschistus heros Fabrícius (Hemiptera: Pentatomidae) is one of the main pests of the soybean crop. Aiming at the population reduction of this insect, an alternative to chemical control is the association of selective products with biological control through egg parasitoids, such as Telenomus podisi Ashmead (Hymenoptera: Platygastridae). The objective of this study was to evaluate the lethal and sublethal effect of insecticides and phytoinsecticides on adult and immature stages of the parasitoid in pre and post parasitism bioassays and sublethal effects. The treatments consisted: Water, Methanol (controls),Annona crassiflora extract,Neem oil, Lufenuron, Thiamethoxam+Lambda-cyhalothrin, Imidacloprid and Acephate. A reduction in parasitism rate of 68% and 30% was observed for pre-parasitism treatments with imidacloprid+beta-cyfluthrin and acephate, respectively, both classified as slightly harmful according to IOBC. The emergence of parasitoids was mainly affected when treated with A. crassiflora, tiametoxan+lambda-cyhalothrin and imidacloprid+beta-cyfluthrin with means below 10%. In the post-parasitism bioassay, A. crassiflora was moderately harmful, reducing 82% of emergence. Among sublethal effects, sexual ratio values below 0.5 indicated absence of females in the treatment with lufenuron and alternating absence and presence of females in the treatment with acephate.