Worst Weevil Outbreak Since 1968 Threatens Trees in Northeastern US

By Mark Leberfinger, AccuWeather.com Staff Writer

July 22,2015; 9:36PM,EDT

 

 

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Parts of the Northeast United States have been overrun this year by the yellow poplar weevil, a native insect that can damage yellow poplar, magnolia and sassafras trees.
The insect is found from Massachusetts, New York, Michigan, Iowa and Missouri southward to the Gulf of Mexico, said Greg Hoover, an ornamental entomologist at Penn State University.
It's unclear why the number of weevils, which may be the largest since 1968, has dramatically increased.
In the northern parts of the yellow poplar weevil's range, cold spring weather can limit the size of this insect's population, Hoover said. However, the cool spring in the Northeast this year didn't limit the population.
A yellow poplar weevil adult and its feeding injury on a tuliptree, or yellow poplar, leaf. (Photo/Greg Hoover)
"In addition to Pennsylvania, this year's outbreak has been reported in Maryland, North Carolina, Ohio, Virginia and West Virginia," Hoover said.
When the weather warms in the spring, adults emerge and may feed on the swelling host plant buds. Mating and egg laying occur from May to early June, Hoover said.
"Following the very active and cooler-than-normal summer we have had up to this point across the Northeast, the rest of the summer into the early fall look to offer near- to above-normal temperatures with less rainfall overall," AccuWeather Senior Meteorologist Jack Boston said.
The large outbreak is causing concern for trees in the region, both for homeowners and for parks and forests.
"Yellow poplar contributes more total volume to West Virginia's forests than any other species; therefore, there is reason for concern," West Virginia State Forester Randy Dye said in a news release.
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"Eggs are laid in the midrib on the lower leaf surface, and newly hatched larvae bore into the leaf tissue to feed as leaf miners," he said.
Up to 19 larvae may develop in one leaf-mining area. Adults feed on plant tissue and may cause the most damage to the plant, Hoover said.
A homeowner may handpick adults from the lower leaf surface on small trees in their landscape, Hoover said.
"If indicated, yellow poplar weevil adults may be managed with registered insecticide formulations containing the active ingredients bifenthrin or carbaryl that should be applied in late June to early July according to all label directions," Hoover said.