Mahoney's Garden Center / Lawn + Garden  / Winter Moth: What You Need to Know

May 17, 2018

Winter Moth: What You Need to Know

winter moth products

Originally introduced to North America from Europe, winter moths, and the devastation they bring can be found  throughout New England – especially in areas around Boston and Cape Cod. They seem to prefer apple, blueberry, cherry and crab-apple fruit trees, but they also feed on oaks, maples and ash. There is no gentle way to say this; it’s a very serious problem.

 

Adult moths emerge from the soil in late November, and females lay their eggs on tree trunks, house siding, and other outdoor surfaces through January. These eggs hatch just before spring buds begin to break. The young larvae—tiny inchworm caterpillars—tunnel directly into the buds to feed, often before the buds even have a chance to open. After consuming a bud, the larvae drift on wind and silk strands—a process known as “ballooning”—to reach the next one. This feeding cycle can cause partial or severe defoliation, and trees that lose their foliage for three consecutive years face a high risk of death.

What You Can Do

There’s no single easy solution, but taking action is critical, as affected trees face serious risk without intervention. In early spring (late March through bud break), spray All Seasons Horticultural Oil from Bonide. This all-natural oil helps prevent winter moth eggs from hatching. If you noticed adult moths last December, don’t wait—larvae can cause significant damage long before they’re easily visible.

Once leaves begin to open, horticultural oil is no longer effective. At that point, switch to Bonide Thuricide or Captain Jack’s Deadbug Brew, both all-natural treatments that control winter moth caterpillars. Thuricide is effective on young larvae, while Captain Jack’s continues to work even as caterpillars grow larger.

To support trees and shrubs that have experienced defoliation, be sure to water deeply once a week throughout the summer. Although all three Bonide products are all-natural, it’s still important to protect pollinators. Never spray plants while they are in bloom. Apply treatments early morning or after sunset, when bees are not active.