University of Illinois Extension
Bruce Spangeberg

These articles are written to apply to the northeastern corner of Illinois. Problems and timing may not apply outside of this area.

Stateline Yard & Garden

Gypsy Moth Numbers
Up in Illinois—Part 2

April 23, 1998

Gypsy moth is a serious introduced insect pest and numbers are expected to be high in Illinois this year. Last week, the gypsy moth and its life cycle were discussed. This week focuses on what is being done about the problem.

For the past several years, the Illinois Department of Agriculture (IDA) has been monitoring the gypsy moth in Illinois. Female gypsy moths cannot fly and release pheromones to attract male moths. Gypsy moth traps are placed throughout suspect areas. Traps are cardboard and triangular in shape with open ends. The pheromone is placed inside, along with sticky material. Male gypsy moths are lured into the trap and then get stuck inside. IDA staff can monitor traps to determine the presence of gypsy moths and relative populations.

In 1996, 2,608 gypsy moths were trapped in McHenry, Lake, Kane, Cook, and DuPage counties. In 1997, that number jumped to 33,714, with the heaviest moth catches near the shore of Lake Michigan from Evanston northward. Michigan has had a significant problem for several years, and numbers also have been high in Wisconsin, especially along Lake Michigan.

When problem areas are identified, the IDA tries to pinpoint exactly where the infestation originated. Control may involve putting out more traps, removing egg masses (in winter), and spraying insecticide. Bacillus thuringiensis, a microbial (bacteria) insecticide is used.

If you suspect gypsy moth, the IDA can be contacted at (847) 294-4343. Remember, gypsy moth caterpillars do not make silken tents. You can also bring suspect caterpillars to your local University of Illinois Extension office for help with identification.

In addition, thoroughly inspect vehicles, campers, outdoor furniture, firewood, and other items coming from infested areas (vacations, corporate moves). Look for the buff-colored, hairy egg masses. Don't purchase trees and shrubs from outside of the area unless they have been inspected (buy from reputable nurseries).

While numbers of gypsy moth have increased significantly, this does not mean our entire area will be infested. Authorities are monitoring the situation and acting accordingly. Citizens and government need to work together to keep this pest under control.


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