Spongy Moth

Notice of Aerial Spraying for Spongy Moth Larvae in Selected Areas of Walker

Certain areas in the City of Walker are scheduled to receive aerial application of the bacterial agent Bacillus thuringiensis (B.t.) for the suppression of Spongy Moth larvae. The good news is that previous applications over the years have dramatically decreased the treatment area. 

The applicator for the program is Hamilton Helicopters, Inc., P.O. Box 264, Hamilton, MI 49419, 616-291-5808. The B.t. brand will be Foray, supplied by Valent Biosciences Corporation. The spraying will be done by aircraft when the weather conditions are suitable. There is no cost to be included in the spray program. At this time, spraying is tentatively scheduled for mid-May and early June. The exact date and time of spraying depend on weather conditions, the insect stage, and leaf development.

The insecticide B.t. is derived from a naturally occurring bacteria and is known only to affect caterpillars by destroying their stomachs after they eat the material. It does not affect honeybees or other non-leaf-eating insects, birds, fish, or mammals. The B.t. is applied in a very fine mist that targets the trees. The carrier liquid is water and drying usually takes place within a few minutes. Additional information regarding Foray and Spongy (Gypsy) Moths in general:

Spraying in the West Michigan area typically takes place in mid-to-late May, weather permitting. It is challenging to say exactly which blocks will be sprayed at a given time. The applicators usually begin around 7 am and stop for the day when weather conditions become unsatisfactory, such as high wind, possible rain, or low humidity. 

• Spongy (Gypsy) Moth Summary (B.t.) (DOC)
• Spongy (Gypsy) Moth Life Cycle Guide (DOC)
• Foray Insecticide Brochure (PDF)

For questions, please reach out to the City of Walker.