Western bean cutworm moths are laying their eggs in corn fields in Pennsylvania. It is important to scout fields for eggs and young caterpillars to understand the threat that this pest species poses to your crops.
The highest numbers of moths have been found in Centre County, so growers in this region should prioritize scouting. High numbers of moths have also been captured in Indiana, Ohio, and Ontario.
Look for egg masses on the upper leaves of corn and young caterpillars feeding on reproductive tissue, including pollen in whorls, tassels, or silks. The caterpillars will eventually find their way to the developing ear.
Corn hybrids with the Herculex 1 trait can help suppress populations of western bean cutworm, but they often do not provide adequate levels of protection. The main Bt trait that can help control western bean cutworm is the Agri sure Viptera trait.
An economic threshold for western bean cutworm is 5% of plants having eggs or larvae. Corn grain and silage fields above this level would benefit from an insecticide application.
The timing of the insecticide application is important. It needs to occur after eggs hatch but before caterpillars enter their ears and are protected from insecticides by husks.
Fields that do not have populations that exceed the economic threshold are unlikely to benefit from insecticides. In fact, they may suffer if the insecticide flares aphid populations.
Young western bean cutworm caterpillars have black heads and yellow, spiny-looking bodies. Later in the season, more mature western bean caterpillars look like corn earworms but do not have lines down the sides of their bodies like corn earworms do. Cutworms also have three distinct light brown lines on their “neck” just behind the head.
By scouting your fields for western bean cutworm eggs and larvae, you can help protect your crops from this pest species.
Photo Credit: gettyimages-nes
Categories: Pennsylvania, Crops, Corn, Livestock