Laboratory evaluation of Gryon pennsylvanicum (Hymenoptera: Scelionidae) as potential biological control agent of Leptoglossus zonatus (Hemiptera: Coreidae)

The western leaffooted bug, Leptoglossus zonatus (Heteroptera: Coreidae), is a significant pest of tree nut crops in California. In almond and pistachio, feeding damage can lead to epicarp lesions, kernel necrosis and stigmatomycosis, resulting in reduced crop quality and/or yield. Due to their rapid and often unpredictable migration behavior into orchards, growers often rely on pesticide treatments to avoid risk of a pest outbreak. Such methods in pest control can be economically costly and environmentally unsustainable. Given the increasing demand for more sustainable pest management options for growers, we investigated the prospects of biological control to improve current integrated pest management programs for the pest. Biological control of L. zonatus was evaluated under laboratory conditions with prominent North American egg parasitoid Gryon pennsylvanicum (Ashmead) to obtain important biological and demographical parameters. This study provides a baseline assessment on the life history and reproductive capacity of G. pennsylvanicum to help determine its prospects as a biological control agent of L. zonatus.