Stink bugs, known for their “sweaty feet” smell when squashed or irritated, have now made their way into Ohio soybean fields in numbers not previously experienced in the Buckeye State, said Ron Hammond, an Ohio State University Extension entomologist. Because the problem has gotten so bad, college entomologists are working on a new fact sheet to address growers’ concerns, he said. http://entomology.osu.edu/ag/images/StB_Factsheet_June_26.pdf The brown marmorated stink bug was finally found in several soybean fields last year in populations large enough to notice after having entered the state a few years ago, said Hammond, who also has an appointment with the Ohio Agricultural Research and Development Center (OARDC).
OSU Extension and OARDC are the outreach and research arms, respectively, of the college.
A native of eastern Asia, the brown marmorated stink bug was first identified in the U.S. in Allentown, Pa., in 2001. The brown, three-quarter-inch insects are known to feed on a wide range of crops, including apples, peaches, tomatoes and soybeans.
Likewise, Hammond said, sightings of larger-than-usual numbers of green stink bugs have also been reported in Ohio soybean fields, as well as reports of the red-shouldered stink bug, which is a newer pest in Ohio.
“Up until recently, stink bugs weren’t in populations large enough to cause a concern in Ohio,” he said. “But as these bugs begin to increase in numbers across the state, the concern for soybean growers is the potential for yield declines due to the pests, which use their piercing-sucking mouthparts to feed on the plant seeds.
“Since these bugs can cause direct damage to the seed, it doesn’t take a huge number of the pests to cause an economic loss, particularly for food-grade soybeans and soybeans grown for seed.”
Hammond said last year was the first time that Ohio growers reported larger amounts of green stink bugs in their fields as the bugs are typically more prevalent in southern states. But with warmer temperatures in recent winters and summers, more of the bugs have begun traveling north, he said.
“We had reports of fields at economic levels last year in Ohio, which are fairly rare to see in our area,” Hammond said. “And we anticipate that to become more prevalent throughout the state.”
To deal with the problems, growers can sample their fields for the bugs, he said.
To do that, growers need to take multiple, 10-sweep samples with a sweep net in multiple locations throughout the field, he said. Then, average the number of stink bugs in the samples.
“The threshold to treat is four or more stink bugs, adults or nymphs,” Hammond said. “If soybeans are food-grade soybeans or being grown for seed, the threshold can be dropped to two or more stink bugs.”
Because stink bugs often occur mainly on the field edges, especially next to woody areas, growers should sample both the field edge and within the field to determine which parts of the field may require treatment, he said.
More information can be found at: http://entomology.osu.edu/ag/images/StB_Factsheet_June_26.pdf .