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Cankerworms Causing Defoliation in Southern Maryland Trees Most Affected Trees Expected to Recover Fully



Canker Worm

ANNAPOLIS, MD – An infestation of spring cankerworms have eaten the leaves off of many trees in Prince George’s, Charles and St. Mary’s Counties; however, entomologists with the Maryland Department of Agriculture (MDA) expect most trees to survive the defoliation without difficulty.

“These green caterpillars are often mistaken for the much more destructive gypsy moth,” said MDA Forest Pest Management Program Manager Bob Tatman, “Their presence, coupled with the obvious defoliation, has led some local residents to express concern about what’s going on. Trees experiencing defoliation due to cankerworms usually recover completely if they are not otherwise stressed.”

Gypsy Moth catapillar

Gypsy Moth Caterpillar

Cankerworms are native insects that have exhibited small one- or two-year outbreaks around Maryland, the last one was in 2007 in Anne Arundel and Cecil Counties. The outbreaks are difficult to predict and more likely to be gone after the second year than to persist. Residents who are concerned about the cankerworm’s impact on high-value trees may want to consider insecticide treatment by a licensed pesticide applicator. In addition, watering and fertilizing may also help keep trees healthy.

For a list of licensed pesticide applicators near you.

To see the difference between gypsy moths and canker worms.

For more info on Maryland Forest Pest Management. Or call (410) 841-5922.


Contact Information

If you have any questions, need additional information or would like to arrange an interview, please contact:

Jason Schellhardt
Director of Communications
Telephone: 410-841-5888

Megan Guilfoyle
Public Information Officer
Telephone: 410-841-5889

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