Physiological selectivity of insecticides to the egg parasitoids Telenomus podisi and Trissolcus teretis (Hymenoptera: Scelionidae)

Telenomus podisi and Trissolcus teretis are important parasitoids of stink bug eggs and their preservation contributes to the ecological management of these pests. This work aimed to evaluate the physiological selectivity of the newest insecticides ethiprole and sulfoxaflor + lambda-cyhalothrin in comparison with thiamethoxam + lambda-cyhalothrin and chlorpyrifos, used to control stink bugs, for T. podisi and T. teretis . Bioassays were carried out in the laboratory following standardized protocols. Six independent bioassays were conducted to evaluate the effect of insecticides on the pupal and adult stages of the parasitoids and the effects of insecticide sprays over the host eggs before parasitism. The insecticides were applied using a Potter tower. Ethiprole at rates of 150 and 200 g/150L H 2 O was classified as harmless (class 1), according to the International Organization of Biological Control to both pupae and adults of T. podisi . When tested against T. teretis , ethipprole was classified as harmless (class 1) and slightly harmful (class 2), but it still was the most selectivity pesticide among studied chemicals. When adult parasitoids of both species were exposed to sprayed host eggs, wasps had similar parasitism. The other treatments trigged more severe negative side effects to the parasitoids, especially to adults. Overall, ethiprole was the least toxic compound and should be preferred in integrated pest management aimed at preserving these biocontrol agents, while the other tested insecticides should be evaluated under semi-field and field conditions to confirm their higher toxicity and be replaced for more selectivity pesticide whenever possible.