Penn State partners to address Republic of Georgia's invasive stink bug problem

October 25, 2017

UNIVERSITY PARK, Pa. — Entomologists from Penn State are working to apply what they have learned by studying the Mid-Atlantic region's brown marmorated stink bug infestation — which peaked between 2010 and 2013 — to  similar recent problems impacting the Republic of Georgia in eastern Europe.

Greg Krawczyk, an extension tree-fruit entomologist and research associate professor in the College of Agricultural Sciences, was at Penn State when the invasive pest first was detected in North America, in Allentown, Pennsylvania, during the summer of 2001. As the state's stink bug population grew, significantly depleting fruit, vegetable, corn and soybean yields, Krawczyk was one of several scientists from more than 10 universities and organizations who formed a task force, funded by USDA, to combat the problem. In 2011, the team received a multi-year grant to study various options for brown marmorated stink bug monitoring and management.

"Stink bug damage on fruit was so significant, some growers were forced not to harvest fruit as no marketable crop was available," he said. "And with no information available about brown marmorated stink bug biology or behavior, we first had to learn about it before we could develop effective management strategies for our farmers."

Nearly 20 years after surfacing in the U.S., brown marmorated stink bugs, and their impact on crop production, are generally under control in Pennsylvania and the other Mid-Atlantic states. "We haven't eradicated stink bugs from our agricultural systems, but we've learned how to manage them," Krawczyk explained.

Some European countries, however, have begun to see the same insect species invading their fields and farms. When combined with fluctuations in climate and some specific local factors, the effects of stink bug infestation can be particularly damaging.

In the Republic of Georgia, the brown marmorated stink bug has taken a particular toll on farmers, who have relied on the government for pest and disease management since the country gained independence from the Soviet Union in 1990. With independence came land reform, during which the government divided arable land into small plots —many only a few acres or smaller — between roughly 700,000 farmers.

These small-scale operations have been unwilling or unable to implement up-to-date scientific advancements or best-practices for controlling insect pests, both native and invasive. After nearly two years of wetter-than-average weather, however, a combination of fungal and bacterial diseases and the now-pervasive stink bug has had a devastating impact on the production and livelihood of these farmers, many of whom rely on a single crop to support their families.

Nikoloz Meskhi, head of the plant protection department at the National Food Agency — a governmental unit in the Republic of Georgia responsible for addressing the detection and presence of invasive pests, registration of new and existing pesticides and farmers education — said that in the past year, the country's production of hazelnuts, its most important export, and corn, a significant source of food for people and animals, has declined dramatically.

"In the western part of Georgia we have about 60,000 hectares (150,000 acres) of hazelnut orchards, and they are the main income for the farmers living there," he said. "In 2015, hazelnut exports accounted for about 150 million U.S. dollars for our country. Last year, damage to the hazelnut crop from diseases and insect pests, including the brown marmorated stink bug, reduced that income by about a third. In some areas, up to 90 percent of the crop was lost."

Responding to what has become an agricultural crisis in the country, Georgian officials representing government and academia reached out to U.S.-based specialists for recommendations and potential solutions for how to monitor and manage the stink bug problem. In November 2016, Krawczyk made his first visit to Georgia on a trip organized by Cultivating National Frontiers in Agriculture, an organization associated with the U.S. Agency for International Development.

In cooperation with researchers from Italy and Switzerland, Krawczyk helped to develop a plan to combat the brown marmorated stink bug in Georgia and to organize training courses at the national, regional and organizational levels for the government and USAID personnel. His recommendations and other written materials quickly were translated into Georgian so they could be communicated to the relevant agencies and farmers.

Since that visit, the Georgian government has implemented many of these recommendations, conducting countrywide monitoring of the pest to get an idea of population size and behaviors, helping farmers adopt management practices and implementing relevant educational programs. Reversing the brown marmorated stink bug infestation in Georgia, however, will not be so simple. The nation's severe infestation indicates that an almost complete shift in management methods and mindset is needed — a joint effort of state, education and extension to help farmers while encouraging them to become more proactive and independent.

Maka Murvanidze, a researcher and associate professor at the Agricultural University of Georgia, Tbilisi, explained how the government, academic and private institutions and USAID are working together to change the way Georgian farmers think about managing their farms.

"The government is trying to change the attitude from doing nothing and waiting for the government to take care of them, to taking care of their farms themselves," she said. "They're doing this by providing advising services, education, extension services and direct action where it is necessary. And our role is to provide recommendations based on what we have learned by working with experts from the United States and Europe and from the results of monitoring activities that have been conducted in Georgia so far."

Meshki and Murvanidze learned firsthand about brown marmorated stink bugs in Pennsylvania when they visited Krawczyk's laboratory and observed activities at the Penn State Fruit Research and Extension Center in Biglerville this fall. At University Park, the visitors met with Shelby Fleisher, a professor in the Department of Entomology, to learn about new aspects of modelling applicable to brown marmorated stink bug populations. Off campus, they visited fruit growers in Pennsylvania to learn from their experience and practices in managing stink bug infestations and interacted with entomologists at Virginia Tech University and USDA's Agricultural Research Service, who are involved with cutting-edge efforts to manage stink bugs in agricultural crops. The experience made them more optimistic about their country's ability to take the necessary steps to overcome the effect of insect pests, including invasive stink bugs, they said.

"The value of the help provided by Penn State in dealing with this issue has been huge," said Murvanidze. "We are very grateful to Dr. Greg because he organized our meetings with people at USDA and Virginia Tech who are dealing with the same problems, so now we also have different perspectives. We will incorporate the knowledge gained during this visit when we are back in Georgia, because it was a huge experience indeed."

Added Meshki, "We know it is difficult to control this pest, but step by step, gradually, we will mitigate the damage. And we are happy because we are working with the exact right people to help us with this problem."

Travel for the Georgian visitors was facilitated by the College of Agricultural Sciences' Office of International Programs.

  • Greg Krawczyk

    Greg Krawczyk is an extension tree-fruit entomologist and research associate professor in the College of Agricultural Sciences. His work includes study of the brown marmorated stink bug, an invasive pest originally from Asia and now present in parts of the United States and Europe.

    IMAGE: Michael Houtz
  • Brown marmorated stink bug

    The brown marmorated stink bug, an invasive pest first discovered in Pennsylvania in the early 2000's, caused extensive damage to fruit and other crops in the Mid-Atlantic area.

    IMAGE: Greg Krawcyzk
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Last Updated October 27, 2017