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Illinois Department of Agriculture

Spongy Moth Treatment Program

Open House presentations to cover spray treatments in northern Illinois

SPRINGFIELD, IL – The Illinois Department of Agriculture will hold eleven open house events to explain its most recent plan to treat parts of northern Illinois for the destructive Spongy Moth (historically gypsy moth).
Spongy Moth is a non-native tree pest. Large populations of the pest are capable of stripping plants bare, leaving them susceptible to disease and environmental stressors. Severe or repeated defoliation can cause tree death. Unlike the Emerald Ash Borer, another non-native pest which feeds exclusively on ash trees, the Spongy Moth is not a picky eater. Though its caterpillars will devour almost anything leafy and green as they feed on over 250 species of plants, they especially prefer many of our trees including oak and willow and even pines.

Male Spongy Moths are brown with black chevron-like markings on their wings and have a wingspan of an inch-and-a-half. Female Spongy Moths are slightly larger and typically white or cream-colored with similar markings. The females cannot fly because of the weight of their eggs.

Infested sites will be treated with applications of either BtK or mating disruption (MD) based upon the determined level of the infestation.

The BtK product is Valent Foray 48B – Organic and it will be applied by helicopter in mid-May, with a second application within the following two weeks. BtK (Bacillus thuringiensis var. Kurstaki) is a naturally occurring bacteria used by gardeners as an environmentally friendly alternative to chemical pesticides. It is important to note that BtK has an excellent safety record and is not harmful to people or animals.

In late June, airplanes will apply the mating disruption product Splat GM-Organic, which is a Spongy Moth-specific pheromone that acts as a sexual attractant and prevents male Spongy Moths from finding females and breeding.
Anyone interested in learning more about either treatment method is encouraged to attend an open house where IDOA staff will be available to answer questions. Those events are scheduled, as follows, to discuss and answer any questions about treatments in the surrounding areas.

Click here for a list of all scheduled open houses in the area.

Our DeKalb Office can be contacted at 815.787.5476. Or email with questions. Keep in mind that our Spongy Moth specialists will be in the field for the spray program as it occurs. You can view treatment blocks (areas) online at the Slow the Spread website.

updated Aug 03, 2023