HARRISBURG, Pa. — Every year, soybean growers face two formidable foes in their fields: Insect pests and disease.
To give growers an edge on dealing with these potentially yield-robbing problems, the Pennsylvania Soybean Board, in collaboration with Penn State Extension, is funding a sentinel plot project. The sentinel project involves scouting 18 fields every week for insect and pest populations, and will be executed by a team of 13 county-based Extension Educators, with assistance from college student interns.
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Weekly results are available online at Penn State Department of Entomology’s website at http://ento.psu.edu/extension/field-crops. Regular summaries will also be included in Field Crop News, a weekly email newsletter produced by Penn State’s Crop Management Team. (To receive Field Crop News or articles, see http://extension.psu.edu/plants/crops/news.)
“By one estimate, annual soybean yields are decreased approximately 10 percent by insects, and a further 10 percent by plant pathogens,” says John Tooker, assistant professor of entomology at Penn State, who heads the program. “But in outbreak years, these pests hold the potential to reduce yields by as much as 25-30 percent.”
To manage these threats to crop production, extension specialists typically recommend an integrated pest management program that relies heavily on understanding local populations of pests and the threats they pose to crop fields.
The information gathered by scouting is critically important in determining whether it’s in the growers’ best economic interest to apply a management tactic. Tooker notes that although the Pennsylvania PIPE (Pest Information Platform for Extension and Education) online system can assist growers by indicating when certain pest species may be active based on temperature and weather data, it does not provide what he calls “ground-truthing.”
“Just because a pest should be active does not mean it will colonize fields and cause economic losses,” said Tooker. “The state-wide sentinel program’s scouting efforts will help growers understand what pest populations are doing on a regional basis, which should prompt growers to initiate their own scouting efforts to gauge actual population sizes and risk to their fields.”
Last year, scouting efforts discovered a range of insects and other pests, including slugs, bean leaf beetles, grasshoppers, brown marmorated stink bugs, and a few diseases, including Downy mildew, Cercospora leaf blight and Septoria leaf spot, though few of these pest species ended up causing economic damage.
“It’s an important message for growers to hear: Pest populations do not develop in every field every year,” said Tooker. “In fact, in many locations pest populations do not develop and pesticide use should provide no advantage. Last year, for example, none of the pest populations exceeded economic thresholds in the sentinel fields we scouted, so none of the fields required pesticide treatments.”
