Stink bugs are complex of multiple species, several of which are important pests in soybean. In recent years, these pests has become a bigger problem for soybean growers across the state. Stink bugs cause yield loss by directly feeding on pods and seeds, and indirectly by lowering seed quality and reducing germination. Stink bug feeding can also create avenue for secondary infestation by pathogens. Stink bugs in high numbers can cause delayed maturity, complicating harvest efficiency.

Around 1980, only two stink bug species were reported in North Carolina soybeans. My recent study of 98 soybean fields across North Carolina found 30 different stink bug species, including 3 predatory species. A majority of those species are rare and are not economically important.

Geographical distribution of these species varied across the North Carolina ecoregions.

• Green stink bugs occur across the state
• Brown marmorated stink bug is more common in the Mountain and Piedmont regions
• Southern green stink bug is more common in southern North Carolina soybean
• Brown stink bug is more common in the Coastal Plain

Overall, more than 50% of the fields exceeded the economic threshold for stink bugs. However, the risk was different among three regions of North Carolina.

• Mountain: 83% of Mountain fields (20 of 24) exceeded the threshold
• Piedmont: 56% of Piedmont fields (18 of 32) exceeded the threshold
• Coastal Plain: 31% of Coastal field (13 of 42) exceeded the threshold

Soybean fields in the southern and mountain regions are at greater risk of reaching economically damaging stink bug populations.

While risk is lower in the Coastal Plain, growers should stay vigilant for localized hot spots that can still push populations above the economic threshold.

Growers should base their decision to treat stink bugs on the economic threshold.