By Dusty Sonnenberg, CCA, Field Leader, a project of the Ohio Soybean Council and soybean check-off
Some Insect pests in soybeans can be very evident, such as defoliators feeding on leaf tissue. Others such as stink bugs can be more stealth in their feeding. Kelley Tilmon, professor of Entomology at The Ohio State University has been doing research, funded by the Ohio Soybean Check-off, to develop more efficient ways of scouting for stinkbugs in soybeans.
“I call stinkbugs a stealth pest because the damage they cause is not obvious to the naked eye as you look across a field like you would see from a leaf feeding insect,” Tilmon said. “The way that stinkbugs feed is that they punch their sharp straw like mouth part directly through the pod wall into the seed and suck on the developing seed and can destroy that seed. It can go unnoticed unless you are looking at the pod very closely.”
Often the issue is not realized until the yield monitor indicates the lower yields, or the farmer sees shriveled up seeds in the grain tank. There is good news for management of stink bugs in soybeans.
“The good news is that stink bugs are a pest that can be managed fairly effectively with insecticides, but you need to know it is there,” Tilmon said. “We have been working on methods to make scouting for stink bugs easier.”
Historically stink bug scouting was done with a sweep net in the standing beans. The challenge has been, that in Ohio, stink bugs are typically emerging as a problem in August when the beans are tall and growing together and difficult to walk through much less use a sweep net in.
“We have been working on a method that allows a farmer to keep tabs on a stink bug population without going into the field with a sweep net,” Tilmon said. “The method involves using a pheromone bait for stink bugs that was actually developed for stink bug monitoring in orchards, and we are trying to adapt it to soybeans.” The bait is paired with a sicky trap that should allow farmers and consultants to monitor the stink bug population from the edge of the field.
Tilmon said there is a good deal more to learn about monitoring stink bugs using sticky traps. “There are a lot more research questions to be answered with this technique, such as how many stink bugs captured are considered to be a problem,” Tilmon said. “Those are the questions we are trying to answer before we role this out as a management monitoring recommendation.”
There are different species of stink bugs found in Ohio feeding on soybean pods. Tilmon said while identifying the species of stink bug can be useful information, at this point, the management is more dependent on the population of the pest.
“It is always good to know what populations of stink bugs are there, particularly if we start to find some resistance to insecticides along the way, but right now the focus should be more on numbers and less on the species when making the management decisions,” she said. “All these species feed in a similar way.”
The common stink bug species found in Ohio soybean fields include Brown Marmorated Stink Bugs, Green Stink Bugs, Redshouldererd Stink Bugs, Brown Stink Bugs and the Spined Soldier Stink Bugs. The Spined Soldier Stink Bug is a predatory stink bug.
A stink bug identification card can be found here.