Gypsy Moth Threatening Northern Illinois

Gypsy Moth Threatening Northern Illinois

The gypsy moth is migrating west, and it has established itself in Illinois.

And the Illinois Department​ of Agriculture is trying to do something about it.

  • If you see a Gypsy Moth in any stage of life, call toll free: 1-866-296-MOTH (6684). 

The Illinois Department of Agriculture will hold two open houses to explain its most recent plan to treat parts of northern Illinois for the destructive gypsy moth.

The two upcoming open houses are outside of Kane County but close enough to get to if you want to learn more.

Voracious Feeders

tree damage by a gypsy moth

The gypsy moth is a non-native pest that feasts on more than 250 species of trees and shrubs, but its preferred food source is oak leaves. Large populations are capable of stripping plants bare, leaving them vulnerable to secondary insect and disease attacks. Severe defoliation also can cause tree death.

Gypsy moth caterpillars consume as much leaf tissue as they can, as quickly as they can, to obtain nourishment to become reproducing adults. Since the caterpillars’ feeding period lasts seven to ten weeks through spring and summer, they can do a lot of damage to young tree leaves. If a tree loses more than 50% of its leaves for more than two years in a row, it will certainly be weakened and may not survive.

A single gypsy moth caterpillar can consume 11 square feet of vegetation during its lifetime so the presence of millions of caterpillars can severely affect trees and forests

Some Background

Lake County, Illinois was quarantined in 2000. Three Kane County neighbors — McHenry, Cook and DuPage — were added in 2007.

A quarantine requires all nursery stock and firewood being shipped out of the affected counties to be inspected and certified, which is a difficult and time-consuming procedure. All nurseries and nursery dealers are also required to treat their property and/or stock, and persons leaving quarantined counties must have all outdoor equipment inspected.

Today, the Illinois Department of Agriculture, along with the STS Foundation, places more than 7,000 traps to monitor populations each year. Each year, the monitoring is tabulated and eradication treatments are decided for the following year.

What The State Is Doing

Infested sites will be treated with applications of either BtK (Bacillus thuringiensis var. Kurstaki), a naturally-occurring bacteria used by gardeners as an environmentally-friendly alternative to chemical pesticides.

The BtK product, Valent Foray 48B – Organic, will be applied by helicopter in mid-May with a second application being done within the following two weeks. It’s important to note that BtK has an excellent safety record and is not harmful to people or animals.

Anyone with any questions regarding treatment is encouraged to attend an open house where any and all questions will be answered. Presentations are scheduled as follows to discuss and answer any questions about treatments in the surrounding areas.

Job Opportunities

For summer job opportunities, email Nancy Johnson at or call her at 815-787-5476.