Abstract
The invasion by Halyomorpha halys (Stål) and an increasing abundance of native Pentatomidae pose a threat to soybean, Glycine max (L.) Merrill, production in northern states. A risk assessment framework was used to provide an initial assessment of the risk of Pentatomidae affecting soybean production in northern states. A caged field study was performed over two years to assess the response of soybean to H. halys feeding. Cages placed over R4 soybean were infested with 0, 1, 2, 4, or 8 fourth-instar H. halys nymphs per 0.3 row-m, and the insects were allowed to feed for 15 to 16 days. Feeding by H. halys on soybean affected yield components, maturity, and quality (i.e., seed injury). Season-long monitoring of soybean fields was performed via sweep net sampling to assess the likelihood of herbivorous Pentatomidae occurring on soybean during plant growth stages susceptible to feeding injury. Adults of herbivorous species were collected at low densities in fields in mid- to late July before collection of herbivorous nymphs. Herbivorous nymphs were first collected in the R3 and R4 soybean growth stages and their abundance peaked during the R6 soybean growth stage. This preliminary assessment indicates that if populations of exotic and native herbivorous Pentatomidae continue to increase in abundance, they will pose a threat to northern soybean production.