Stink bugs widespread in Missouri soybeans

COLUMBIA, Mo. – Stink bugs are an all-too-familiar foe for Missouri soybean growers, but new University of Missouri research shows just how widespread they are, and how farmers can better time and target their scouting.

In a statewide study spanning the 2024 and 2025 growing seasons, University of Missouri researchers used sweep nets to survey 316 commercial soybean fields, collecting more than 2,700 stink bugs representing nine species. The study, led by MU Extension entomologist Ivair Valmorbida, was published in the journal Environmental Entomology.

“These results provide the first comprehensive, statewide assessment of stink bug community and spatial distribution in Missouri soybeans that can be used to improve scouting timing and management decisions,” says Valmorbida.

One species dominates

One species rules the field. The green stink bug (Chinavia hilaris) accounted for more than 80% of all stink bugs collected. Other species included the one-spotted stink bug (10.55%) and brown stink bug (5.89%). Each of the remaining species made up less than 1% of the total.

Two other stink bugs have been detected in Missouri soybeans over the past 25 years: the red-banded stink bug and the brown marmorated stink bug, with the latter detected in the present study.

Edges tell the story

Populations of green stink bugs were significantly higher along field edges than in field interiors. Stink bugs typically move into soybean fields from nearby wooded areas, crop residue and other protected habitats before spreading inward.

These findings suggest that field borders are important early scouting locations, although whole-field scouting remains necessary to monitor population dynamics and make accurate management decisions, says Valmorbida.

Watch the calendar

Timing is just as important as location.

Stink bug numbers remain low early in the season but increase rapidly beginning at the reproductive growth stages, and peaking at R6, or full seed. This is also when soybeans are most vulnerable. Stink bugs feed on pods and developing seeds. This can reduce yield, damage seed quality and delay maturity and timely harvest.

Different landscapes, different pressure

Missouri’s varied soils and landscapes play a role in stink bug pressure.

The study found that the abundance and diversity of stink bugs varied by ecoregion. Some areas had higher overall populations, while others had greater species diversity.

More diverse landscapes with forests, pasture and cropland may offer more habitat for different stink bug species.

Invasive species not yet major players

While invasive stink bugs have raised concerns in other regions, Missouri growers are seeing limited impact for now.

According to the study, the brown marmorated stink bug was found in only a few locations and at low levels. The red-banded stink bug, another potential pest, was not detected in this study.

Economic impact

Missouri ranks as the seventh-largest producer of soybean in the United States, with more than 5 million acres grown annually. The stink bug complex is considered the costliest pest across 19 major soybean-producing states, with estimated yield losses exceeding 12 million bushels.

Smarter scouting, better decisions

The findings give growers a roadmap for managing stink bugs:

• Start scouting at field edges.
• Increase monitoring during pod fill and seed development.
• Adjust management based on regional differences.

According to the study, these patterns can help farmers optimize scouting efforts and improve management decisions across Missouri soybean fields.

“For Missouri producers, the takeaway is simple: pay close attention to field edges, monitor fields carefully during reproductive growth stages, and continue scouting throughout the field as the season progresses,” says Valmorbida.

Photo

The green stink bug accounted for more than 80% of all stink bugs collected in a recent MU study of Missouri soybean fields. Photo by MU Extension state field crops and forage entomologist Ivair Valmorbida.