Scouting for Brown Tail Moth Egg Sacks

Wendy Reinemann

Scouting for Brown Tail Moths can help protect the plants in our gardens and help to reduce next years caterpillar population.

By now most of us living in Midcoast Maine have come to despise the Brown Tail Moth due to the awful rash that comes from contact with the toxic hairs that cover the caterpillar. While the majority of the moths are living in the forests in the area, they do invade our yards and gardens. We can do our small part to help minimize next seasons impact and protect our trees and shrubs by doing some scouting now for the egg sacks.

First a bit of background on their lifecycle. This is the time of year when the adult Brown Tail Moth begin to lay their eggs that will mature next spring in the caterpillar. Each female will lay between 200 – 400 eggs in a fuzzy light brown egg sack. These egg sack will mature over several weeks prior to the larvae hatching in late August through early September. The larvae will minimally feed on the plants before spinning their winter webs. To make things more complicated the moths will lay their eggs on a wide variety of trees and shrubs. They tend to prefer trees like oak and birch, as well as fruit trees like apple and cherry, but also prefer plants in the rose family.

So, now is the time to scout your gardens and destroy the egg sacks. To scout for the egg sacks, look at the underside of the leaves for a fuzzy light brown egg sack and scrap it from the plant. This will prevent the eggs from maturing into larvae. Scouting should happen every week if possible, through mid-August. While scouting for the egg sacks, you can also scout for other insect and diseases that maybe effecting your plants. Once the hatched there are some organic sprays that can be used to kill the larvae.

It does take time and effort, but it will help protect your plants and help reduce the population of caterpillars next spring.

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