• How did gypsy moths get here?
• What is so bad about gypsy moths?
• When should I look for the caterpillars?
• What do their eggs look like?
• What kind of trees to the gyspy moths kill?
• How do I get rid of gypsy moths?
• Who do I contact if I need more information?
• Where can I get more information?

How did gypsy moths get here?

Gypsy moths are an exotic species brought to the US in 1869. They were brought to this County by a French entrepreneur for silk production. Unfortunately, the species escaped the lab. Having been familiar with the moths, he warned the authorities of their voracious appetites. The Ag authorities did not take the problem serious and thus, we have them here today.

The gypsy moth itself is harmless. The caterpiller however, may cause some allergic reations. The main problem is their voracious appetite. In additon, the female can lay thousands of eggs. Because of this, they have been know to wipe out entire forests. Trees need their leaves to carry on photosynthesis. Defoliation can weaken already stressed trees and they will not survive.


Widespread defoliation allows for the sun to dry soil and futher add to stress. Forest life may depend on these trees and the cover they provide for survival.

The caterpillers most heavily defoliate trees from mid-June to mid-July. It is easiest to see the caterpillars as they grow to about 1 1/2" to 2". They are "hairy". There are very noticable blue and red dots of colors on their backs. The set of blue dots are towards the head, the set of red towards the back.

Egg masses are easily spotted once you know what you are looking for. The masses can be found just about anywhere including lawn furniture, playground equipment, houses. rock walls, cars, and shutters. Most ofen, I have noticed them on oak trees and log piles. They are produced in July and August and remain on the tree until spring and persist well after the caterpillars hatch in May. They are buff yellow, light tan in color, resembling that of a manila envelope or just a bit darker. They also appear "fuzzy" or "furry" almost like felt (these hairs are from the female moth's body used to make the nest). When the "fur" is rubbed, tiny round, hard clearish balls are found underneath (eggs). Masses are usually tear drop in shape and range in size from 1" to 3" long.

Preferred species include:


alder, aspen, white birch, oaks, willow, apple, basswood, hawthorn, tamarack, and witch hazel.


Tree species that are acceptible to the caterpillar, but not preferred include:


beech, yellow birch, black birch, butternut, chestnut, elms, hickories, juniper, pines, walnut, box elder, cherries, cottonwood, hemlock, ironwood, maples, and spruces.


Tree species avoided by the caterpiller include:


ash, red and white cedar, locusts, scotch pine, balsam fir, dogwoods, and mountain maple.

There are several means of control for the moths and caterpillers. I have tried to break them down. I am sorry if I have missed any. Please let me know.


Aerial Spraying:



This is probably the most effective method of control for blocks of areas. A spray by the brand name "Gypchek" is used in our area. It is a virus that settles on leaves, is eaten by the caterpiller, and destroys the gut.


There are limitations and costs to getting into the program to have your area sprayed. First, you must have at least 20 contiguous acres in a compact and regular shape (or have neighbors willing to participate that would equal the same). The lands to be sprayed must have a canopy of cover at least 50%. At least 50% of this cover must be of the gypsy moth's preferred species listed by the State of Wisconsin. Finally, you must have at least 1000 egg masses per acre (500 per residential area).


Costs associated with aerial spraying are can be somewhat estimated. The application fee for the DNR to come out and check the eligibility of a property is $150 at last check. If the eligibility inspection reveals that you are not accepted into the spray program, you will not be returned the fee. However, if you are eligible, the fee is applied towards the spraying cost sharing fee. Right now that cost sharing fee runs approximatly $20-$30 per acre. Latest estimates this year put it at $22.50 per. Note that in Waushara County, a DNR volunteer will come out to appropriate properties to see if an application should be filed. If he determines that it is not, you will avoid having to pay a fee and lose it.



Physical Removal or Spraying of Egg Masses:


This is a very effective method of control but requires some work. Each egg mass destroyed is about 600 to 1000 less caterpillers. In fall, examine trees for the egg masses. Masses you can reach can be scraped into a coffee can, being careful not to drop any on the ground. The eggs should be soaked in soapy water for 2 days or microwaved for 2 minutes to kill them. They then can be discarded in the trash.


If you prefer, the eggs can also be sprayed with a special soybean oil. The DNR recommends using Golden Pest Spray Oil by Stoller Enterprises. The active ingredient in the product coats the eggs and suffocates the larva. Dispersants in the product keep a fine emulsion so that it penetrates the egg. SOYBEAN OIL BY ITSELF WILL NOT PENETRATE THE EGG MASS HAIRS! The only drawback to using this product is that it is only effective applied in temperatures above 40 degrees F. For a GPSO distributer, contact Prince Corporation at 1-800-777-2486. NOTE that if you are planning on applying for the spraying program, don't remove the masses. The DNR will be counting the masses to make a determination as to whether your application is accepted. After they come out to your property, you may start removing masses if you'd like.



Moth Trapping:


Male moths can be killed in specialized traps that are available to the public. These traps are baited with a phermone lure that attracts the males. Females cannot fly. If you would like more information on the traps, please contact me.



Reduce Breeding and Nesting Sites:


Another effective means of control is to remove dead trees and branches, thourougly cover firewood, remove signs, decorations, bird houses nailed to trees, and get rid of tires, barres, cans, garbage, trash, and debris.



Place Barrier Bands:


Barrier bands are sticky bands that entangle caterpillers as they crawl up trees. These bands should be placed in late April and not taken down until August. Be sure to use duct tape around the tree first to prevent the barrier jelly from staining or damaging the tree's bark. A brand name of barrier jelly is Tanglefoot.



Burlap Band:


Burlap bands are used to collect older caterpillers (June or July) that crawl down the trees early in the morning to hide from predators. Caterpillers crawling back up the tree, encounter the burlap flap and hide in the fold. A band can be constructed and caterpillers disposed of in the following manner:


1. Cut a strip of burlap about 18 inches wide and long enough to go around the tree. Wrap the burlap around the tree where it will be easily examined. Tie a string or duct tape around the bottom of the burlap band. Tie a string around the burlap about 6-8 inches from the top. Allow for the top 6-8 inches to flop back over the string you just tied to form a two teired skirt.


2. Check the bands every day from about noon to 7 P.M. Use a stick or other instument (gyspy moth caterpillers can cause an irritating allergic rash if touched) to flick them into a coffee can filled with soapy water. They can be buried or dispoed of in the trash.


Plant non-Preferred Trees and Bushes:



Planting non-preferred trees and bushes can help to limit caterpillers by removing ideal food sources. Competition for food can break high caterpiller populations. Gypsy moth populations are cyclic, surging about every 10 years. During two cycles, trees in a lot can be established to limit impact of the moth. Certainly, increasing tree diversity in woodlots is a good thing.



Do Nothing:


Many beleive that doing nothing is a form of control. They believe that allowiing for the natual course of the insect will produce resistant trees. More likely, non-preferred species will replace preferred ones. Either way, this natural progression will, in theory, limit the progression and damage done to the forest canopy over time. The problem with the theory is that a genetic mutation that changes the diet of the moth may be very likely. The higher the poplation (generation) rate, the more likely a mutation.

Our area contact for the gypsy moth suppression program is Bill McNee. He can be reached at 1(920)492-5930.

Wisconsin has a great Website dedicated to gypsy moth education. It can be found at http://www.gypsymoth.wi.gov/.