In the United States, California (CA) is the primary commercial producer of 
pistachio nuts, Pistacia vera L. (Anacardiaceae). The brown marmorated stink bug 
(BMSB), Halyomorpha halys (Stål) (Hemiptera: Pentatomidae), an invasive and 
polyphagous insect pest from Asia, has established in urban areas in several 
pistachio-growing counties in CA. Breeding BMSB populations have not been 
detected in commercial pistachio acreage. However, the detection of BMSB in Kern 
and Fresno counties, major Kerman pistachio producing areas in CA, underscored 
key knowledge gaps on BMSB ecology in CA and motivated investigations on the 
susceptibility of pistachio nuts to BMSB feeding. Laboratory feeding trials 
conducted in quarantine under permit indicated that adult BMSB stylets can 
penetrate developing pistachio shells and associated feeding was correlated with 
kernel necrosis for nuts collected mid to late season (June to August 2016). 
Feeding damage estimates indicated that higher levels of kernel injury were 
associated with female BMSB when compared to feeding by male BMSB. These results 
suggest that there is probable risk of feeding damage to field grown pistachios 
from BMSB. The implications of this study for BMSB pest management in the CA 
pistachio system and future research directions are discussed.