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Gypsy Moth
Important Gypsy Moth Information Photo of Gypsy Moth Egg Masses

Gypsy moth is now established in the City of Stevens Point. The gypsy moth is an aggressive feeder in the caterpillar stage. It will feed on nearly 500 different kinds of trees and shrubs, and can defoliate them quickly. The City of Stevens Point sprayed over 100 acres in 2004 in its effort to control the gypsy moth. Because the spraying was so effective, and with the help of Mother Nature, no land in the city has needed to be sprayed since then. The spring and early summer of 2004 were cool and moist, which is ideal for the growth of a fungus which attacks and kills gypsy moth. This fungus had a banner year in 2004 and wiped out much of the gypsy moth population throughout the city. Hopefully, it will be a couple years before the city will have to consider spraying again.

In early May, the gypsy moth caterpillars emerge from their egg masses and begin feeding on the leaves of trees. Their preferred tree is oak. As the caterpillar gets larger, so does its appetite.

By June, the caterpillars can be a real nuisance, just by their large numbers, as well as by the hairs they possess which can cause a rash to many humans when touched. Photo of Gypsy Moth Caterpillars

The caterpillars feed until late June to early July. This is when the defoliation from their feeding becomes very apparent - the trees will be stripped of all their leaves.

From late June to late July, the gypsy moth spends its life in a pupae stage, which is similar to a cocoon. From this emerges the adult moth, and those live until about September.

It is during this time, from August to September, that the female moth lays her eggs in masses. She will deposit her eggs anywhere and everywhere - in firewood piles, under campers, trailers, cars, in cracks of trees, etc. Each egg mass can contain between 600-1000 eggs. Photo of Gypsy Moth Laying Eggs

From September until May, the gypsy moth remains in the egg stage.

What Can You Do?

In areas where gypsy moth is known to exist, it is important to inspect outdoor materials for gypsy moth life stages, this is especially true when you are transporting items from one area to another. Be familiar with what the caterpillars look like (see above), and be familiar with what the egg masses look like (see above). If you're hauling firewood to your family cottage and you find gypsy moth caterpillars on the wood, crush them, spray them, but do not transport them to a new area.

If you find Gypsy moth egg masses, you can spray the eggs with a soy bean oil product call Golden Pest Spray Oil, or scrape the eggs into a microwaveable bag, "nuke" them for one minute, and then discard them. Simply scraping the eggs off and trying to crush them with your foot doesn't work. Photo of Gypsy Moth Egg Masses

Once the caterpillars hatch, there are a number of things you can do. When they first hatch in May, you can put a piece of duct tape around the infested tree at chest height, and then spread "Tanglefoot" onto the tape. The young caterpillars will get stuck in this as they move up and down the tree.

Or, you can try putting up burlap bands. Cut a strip of burlap 12-18 inches wide and wrap it around the infested tree at chest height. Then tie a string around the tree on top of the burlap with six inches of burlap overhanging the rope. Many caterpillars will seek cover under the burlap during the afternoon. Once a day, you can check the burlap bands and dispose of the caterpillars found inside. You can crush them, or brush them into a bucket of soapy water. Once the caterpillars are dead, drain the water and throw them in the trash. Photo of Gypsy Moth Spraying

The caterpillars can be sprayed with insecticide. Make sure the insecticide is labeled for controlling gypsy moth caterpillars. There are some insecticides that are more caterpillar specific than others, and will not harm other beneficial insects. Choose your insecticide wisely, and always follow the label.

What is the City of Stevens Point doing to Control this Pest?

The City of Stevens Point Forestry Dept is doing a number of things to help control the gypsy moth in our community. First, we have been monitoring gypsy moth populations within the city, as well as keeping track of populations state wide. Photo of Gypsy Moth Caterpillar Trap

One of the largest buildups of gypsy moth is at the city's east boundary. This means we can expect the populations of the pest to continue to grow in Stevens Point. Whenever the department is notified of a gypsy moth complaint, or our staff finds any life stage of the moth, it is recorded and plotted on a map. This helps identify potential spray areas.

A big thrust has been made to inform the public of the insect. The local newspapers and radio stations have been very helpful in covering this story. Residents have been kept up to date through the city newsletter and this web site. There are brochures on controlling the gypsy moth available at the Stevens Point Forestry Dept.

Forestry Department personnel have been spraying egg masses as we find them. The egg masses are sprayed with Golden Pest Spray Oil, which is available at most area garden centers. Very few egg masses have been found on city street trees. Their locations have been noted, and the egg masses will be sprayed once the temperature stays above 32 degrees. Photo of Gypsy Moth Spraying

There is a fungus disease (Entomophaga maimaiga) and a virus (NPV) that are specific to infecting gypsy moth caterpillars. The disease and virus are fatal to the caterpillar. The forestry department has been collecting caterpillars killed by the disease and fungus, blending them up, and introducing the "cocktail" to new pockets of gypsy moth infestations in the hopes of the virus or disease taking hold.

The city will continue to monitor this pest. We will try and keep our residents updated and informed of the gypsy moth. Hopefully, with a proactive approach, we can control the pest. If you have any questions, you can call the City of Stevens Point Forestry Department at 346-1532.

You can also find more information on the gypsy moth on the Wisconsin gypsy moth Website.

View the United States Department of Agriculture Gypsy Moth Handbook.

EEK! Environmental Education for Kids "Changing Faces of the Gypsy Moth"

City of Wonderful Water
City of Stevens Point, 1515 Strongs Ave., Stevens Point, WI 54481 | Phone 715-346-1569