Tree-killing gypsy moth caterpillars at it again, what it means for your foliage

Local News

IRONDEQUOIT, N.Y. (WROC) — You might have gypsy moths, or gypsy moth caterpillars and not know it. If left untreated, it could mean a beloved tree at your house could eventually die.

If you’ve got some leaves sprinkled with holes, it might be time to call in a tree specialist.

Arborist Noreen Riordan with Monster Tree Service says the gypsy moth made its way over here by accident from the old world in the 1860s. In North America, it does not have any natural predators. 

“The gypsy moths tend to come in series of three-four years or eruption in a row,” says Riordan.

There is a virus that spreads and kills them off, but when conditions are right, the virus isn’t effective. That’s been the case this year. 

“They lay these little egg casings that are filled with 200 to 1,000 eggs,” Riordan says.

As caterpillars, they feed on leaves, killing the foliage. Riordan says if a tree loses its leaves, where its food is made, it could die.

The caterpillars and moths are also irritating to human skin, people tend to think the reaction is from poison ivy at first.

“I met someone who was out camping and their neck was all covered in a rash,” says Riordan.

When they become moths, the egg-laying process starts all over again. Some trees they like to attach themselves to are white oak, maple, pine, and spruce.

“I saw a number of them, all over the tree, so we were very concerned,” says Sue McCarthy, her tree covered in white sacks and ‘swiss leaves’.

McCarthy is getting an insecticide injection done to get rid of the insects. She says they’d hate to lose a tree in their front yard.

“That’s one of the reasons we bought this house, because of the foliage,” she said.

It could also mean a dip in their property value.

Riordan says to also look for pupal cases and egg masses

In Canandaigua, the Canandaigua Lake Watershed Association rallied participants to do a ‘scrape-a-thon’ and get rid of the egg masses on trees.

In a press release, they said, “CLWA calculated the events in total prevented 22,014,400 gypsy moth caterpillars from reaching adulthood and continuing to negatively affect already stressed hardwood trees in the parks.” The full CLWA article can be found here.

Riordan says if left untreated, the gypsy moths and all their offspring will soon return, and in greater numbers for years on end. “A tree this big is not going to able to survive,” she says pointing at the oak next to her.

Riordan says there is a limited window to get your tree an insecticide injection by a certified applicator. When the caterpillars start to feed on the foliage, she says they will die, and hopefully rid the tree of the pests.

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