Oct 2, 2019

Simpler trap for monitoring brown marmorated stink bugs eyed

What’s better than one scientist studying the optimal design for traps to detect brown marmorated stink bugs? How about 35 scientists conducting the same tests across 115 sites in 18 states across the country?

That’s the level of collaboration that went into a new study that establishes the reliability of a simpler, more cost-effective monitoring trap for brown marmorated stink bugs. The results of the project, published in September in the Journal of Economic Entomology, will make it easier for growers and integrated pest management (IPM) professionals to measure the presence of brown marmorated stink bugs and decide if and when management methods are necessary.

Since its arrival in North America in the 1990s, the invasive brown marmorated stink bug (Halyomorpha halys) has spread to 44 states in the U.S., becoming an agricultural pest in at least 25 states and causing nuisance problems in seven more. In 2014, researchers discovered the insect’s male aggregation pheromone, and others have later established its effectiveness in attracting the bugs using a black pyramid-style trap. That trap type, however, can be cumbersome to deploy.

So, a team of researchers led by Tracy Leskey, Ph.D., at the U.S. Department of Agriculture-Agricultural Research Service’s Appalachian Fruit Research Station in Kearneysville, West Virginia, got to work on a new-and-improved solution. In a study published in 2018, the team showed the similar effectiveness of a clear sticky-panel trap using the same H. halys aggregation pheromone. The next step was testing that result on a broader scale.

“We wanted to use enlist collaborators around the country to evaluate these two baited trap types in different agroecosystems and under varying climactic conditions,” Leskey says. “Not only would this tell us how each trap type performed, but it also would provide data nationwide on relative abundance and seasonal phenology of H. halys populations.”

Angelita L. Acebes-Doria, Ph.D., a postdoctoral researcher at Virginia Tech working with Leskey’s lab at the time (now an assistant professor of entomology at the University of Georgia), developed a standard protocol for testing the trap designs and coordinated the participation of colleagues across the country. In all, the traps were deployed at 115 sites in 18 states and checked weekly from April to November 2017. The resulting mountain of data showed consistent results with the earlier small-scale testing.

“Although the pheromone-baited black pyramid trap captured more H. halys than the baited clear sticky trap, the captures between the two traps are strongly correlated regardless of the relative population density,” Acebes-Doria says. “Thus, both trap designs are good options for monitoring brown marmorated stink bug populations, with sticky panel traps offering a simpler alternative.”

Leskey says the study is “the culmination of a decade of work on the chemical ecology” of H. halys. Now the simplified monitoring traps can be deployed in varied agricultural settings. “We want to develop standardized treatment thresholds – i.e., decision support tools – for cropping systems to improve integrated pest management programs,” she says. “While a threshold was developed using black pyramid traps, the lures used were experimental. Now, we have standardized traps and lures to establish thresholds for particular crops.”

The large, coordinated trapping of H. halys in 2017 also gave the researchers a chance to test models of the bug’s seasonal life cycle dynamics against real-world data. Acebes-Doria says the two were “reasonably comparable” for adults but not for nymphs. Continued trapping would allow the models to be further refined. “This would hopefully lead to development of more accurate H. halys population forecasting models, which could benefit agricultural production as well as the biosurveillance of this invasive pest,” says Acebes-Doria.

That monitoring will also be important as researchers track the effects of the parasitoid wasp Trissolcus japonicus, which is viewed as a strong potential natural enemy that could aid in bringing H. halys under control in the U.S.

“It is because of the cooperative, collaborative, and integrated approach to research and extension at a national level that we have made rapid advances for the management of the invasive H. halys,” Leskey says. “Programs that enable this type of dynamic, cross-institution project development and execution are key.”

– Journal of Economic Entomology

Photo at top: A new study conducted across 115 sites in 18 states in the U.S. shows a clear sticky-panel trap using the aggregation pheromone of the brown marmorated stink bug (Halyomorpha halys) as a lure to be a reliable tool for monitoring local populations of the bug in various agricultural and environmental settings. Photo: Tracy Leskey