Dinotefuran toxicity on predators and egg parasitoids of Piezodorus guildinii and Dichelops furcatus (Hemipetra: Pentatomidae) under field conditions

Abstract

Piezodorus guildinii and Dichelops furcatus stink bug populations are naturally regulated by predators and egg parasitoids. However, these natural enemies can be affected by the application of non-selective insecticides commonly employed for stink bug chemical control. This study aimed to evaluate the dinotefuran toxicity on predators and egg parasitoids associated with P. guildinii and D. furcatus (Hemimpera: Pentatomidae) populations under field conditions. Predators and egg parasitoids were recorded weekly from V2 to R7, in dinotefuran-treated and untreated soybean plots. Telenomus podisi (Hymenoptera: Scelionidae) was present on 100 % of the egg masses parasitized on both stink bugs species and treatments. No significant differences were found in parasitism proportion and sex ratio between treatments for either species. The egg mass emergence proportion showed significant differences among the treatments for P. guildinii, but not for D. furcatus. The dinotefuran application did not affect the presence of generalist predators as Araneae, Syrphidae and Chrysopidae. Dinotefuran can be considered selective for these predators, but not for P. guildinii.

KEYWORDS: Telenomus podisi, stink bug, biological control.