A dry summer helped gypsy moth populations in Wisconsin and set back efforts to prevent the pest from spreading.

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) caught 99,647 gypsy moths this summer in traps as part of a program to slow the spread. It was the second consecutive year of increases and the most since more than 108,000 were captured in 2017.

“Wisconsin experienced far less rainfall than usual during the spring and early summer,” said Michael Falk, DATCP’s trapping coordinator. “These dry conditions limited the spread of diseases known to kill L. dispar caterpillars. As a result, more caterpillars survived to adulthood and populations increased for a second consecutive year.”

Officials are asking people to keep an eye open over the winter months for moth egg masses, which are tan, oval or bulb-shaped, and usually a little bigger than a quarter. The egg masses are velvety and are found on trees, vehicles, fences, playground equipment and buildings.

To remove an egg mass, use a putty knife, stiff brush, or similar hand tool and place the mass into warm, soapy water. Soak for a few days and then discard in the trash. You can also spray horticultural oil onto egg masses. Simply crushing an egg mass will not destroy it.

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