University Park, Pa. -- A researcher in Penn State's College of Agricultural Sciences has received funding to study how Pennsylvania fruit growers can limit crop damage caused by brown marmorated stink bugs.
Funded by a $50,000 grant from the Pennsylvania Apple Marketing Board, Greg Krawczyk, extension tree-fruit entomologist, has begun a two-year investigation into the increasingly serious problem posed by this invasive stink bug species.
Pennsylvania is the fourth largest apple-producing state in the country, and experts estimate that 10 to 20 percent of the state's 2010 fruit crop was affected by the pest.
"As the brown marmorated stink bug population continues to increase in our state, so does the devastation that they bring to our apple crops," said Karin Rodriguez, executive director of the apple-marketing program, in announcing the grant. "We need to start combating this problem now to help our growers minimize future crop loss."
Krawczyk, whose laboratory is located at Penn State's Fruit Research and Extension Center in Biglerville, Pa., pointed out that the brown marmorated stink bug presents a formidable challenge because it is so adaptable to mid-Atlantic conditions.
"Its presence has been confirmed in 32 states, with the mid-Atlantic states feeling the greatest impact," he said. "And because the number of plants on which it can feed is so great, there is a tremendous challenge in developing effective control strategies."
The timing of Krawczyk's field research is critical, according to Mark Seetin, director of regulatory and industry affairs for the U.S. Apple Association.
"More than 50 of the country's scientists at state and federal research institutions have joined together to seek a $9.6 million research competitive grant under the U.S. Department of Agriculture's Specialty Crop Research Initiative," he said. "But those funds to study control of stink bugs, if granted, will not be available until October of this year."
The funds that Pennsylvania's apple growers are dedicating to this problem allow Krawczyk to immediately begin stink-bug research, according to Rodriquez. "He has started to look for ways to control the pest in the short-term, and he will continue the research effort long-term by studying the species' biology and life cycle," she said.
When Pennsylvania's plant infestation began last summer, Krawczyk conducted two short-term field projects to evaluate the effect the brown marmorated stink bug was having on the apple and peach crops. Now, as the problem continues to grow, the focus has turned to studying and understanding the biology and nature of the insect in hopes of creating a longer-term solution.
But the necessary short-term management options in orchards still need to be developed and evaluated, and that's why this research is so important, Rodriquez noted.
Unlike other stink bug species that are indigenous to Pennsylvania and the mid-Atlantic region, the brown marmorated stink bug does not have an effective native natural predator or parasitoid, Krawczyk pointed out. The pests overwinter in houses, barns and old structures, and in the spring they move freely to the fields and other vegetation to reproduce.
"They are constantly in motion, and there is no exact timeframe for reproduction -- it begins sometime in May and continues through mid-October, depending on weather and food sources," he said. "The brown marmorated stink bug is able to feed and develop on more than 300 different host plants, making this a problem for the entire agricultural community, as well as for homeowners."
"Put these factors all together and this creates a pest that is extremely hard to control."
Krawczyk's immediate research will focus on possible management options while still trying to understand the biology and behavior of the pest. "Available pesticides are effective in controlling this stink bug, but we hope to find ways to manage brown marmorated stink bugs by preventing or deterring them from even entering the fields or orchards," he said.
"We’re hoping to learn many things, such as what factors tell the stink bug to move from one place to another. Also, what impact does the surrounding vegetation have on their migration from one orchard to the next? We are investigating whether we can control the population when they are at the first few rows of vegetation -- before they reach the center of the orchard."
Krawczyk is now working in his lab, evaluating currently available products that can be recommended to fruit growers for the best possible management options for this year's crop.
"Pesticides are a temporary stop for a growing problem," he said. "But as more scientists across the country begin to bring attention to the brown marmorated stink bug, I am optimistic that within a few years, a longer-term solution will be found and utilized."