Excerpt from the article “Large and Small Bug Control in Pistachio” by Phoebe Gordon, UCCE Madera and Merced, and Houston Wilson, UC Riverside on the San Joaquin Valley Trees and Vines website.
There are a handful of species that attack pistachio fruit, broadly classified based on their size. Small plant bugs will feed on pistachios, but rarely cause economic damage. Large plant bugs are the more severe pest, and some such as leaffooted bug (LFB) can feed on pistachio fruits until harvest. We do not advocate preventative pyrethroid use to try to keep these insects down. There are very few registered insecticides that control large and small plant bugs and losing them because of evolved resistance from overuse could be devastating. Additionally, using these products can lead to issues with other pests, so it is best to use them only when needed. However, it is important to keep an eye on your orchards to stop these pests once they do appear.
Read the full article on San Joaquin Valley trees and Vines.