It’s time for soybean farmers to be on the lookout for stink bug as the crop develops pods, say Ohio State University Extension entomologists Kelley Tilmon and Andy Michel.
Scouting now is critical because soybean damage often goes undetected until harvest.
“In 2016 a number of farmers had significant stink bug damage but didn’t realize it until harvest, when they discovered shriveled, blasted seeds,” Tilmon and Michel report in the latest issue of C.O.R.N. newsletter. “Both nymphs (immatures) and adults feed on the developing seed by using their piercing/sucking mouthparts to poke through the pod. Seed that is fed upon will take a flat or shriveled appearance.”
There are several species of stink bugs that can be found in soybean, including the green, the brown, the red-shouldered and the brown marmorated stink bug (BMSB).
The heaviest populations of stink bug are usually found in the Eastern Corn Belt, particularly in the mid-Atlantic region, but the BMSB is increasingly found in the central U.S.
University of Nebraska-Lincoln Extension entomologists are encouraging soybean farmers in the state to scout for stink bug this season. “Planting dates were late in many areas and cool weather has slowed plant growth, leading to delayed maturity in many areas. These late maturing crops may remain vulnerable to pest injury longer than usual,” they write in the online newsletter Cropwatch.
Ohio’s Tilmon and Michel write that seed damage can be prevented by scouting and treatment at appropriate threshold levels:
“Most insecticides labeled for soybean include stink bugs on the label, and most are adequately effective. Keep in mind it is easier to kill immatures than adults. To sample for stink bugs, take multiple 10-sweep samples with a sweep net in multiple locations throughout the field. Average the number of stink bugs in the 10-sweep samples. The threshold to treat is four or more stink bugs (adults and nymphs combined). If soybeans are being grown for seed, the threshold can be dropped to two or more stink bugs.”
DuPont Pioneer offers these additional management considerations, with particular emphasis on the BMSB:
- Scout soybeans from R2 till mid-August.
- Scout field edges especially, and treat them separately if warranted.
- In soybean, the threshold is 2.5 to 3.5 brown marmorated stink bugs every 15 sweeps.
- Populations will be highest at dusk and dawn, and reinvasion is possible after a pesticide treatment.
- Many insecticides are labeled for stink bug control; however, brown marmorated stink bug may be more tolerant of many pesticides than other stinkbugs.
- Nymphs are more sensitive to insecticides than adults.
- Check local control recommendations, and always read and follow label instructions