Spray Block Maps and Information

DNR Aerial Treatments

The Wisconsin Department of Natural Resources (DNR) organizes aerial spray treatments on DNR-managed lands, such as state parks and forests. 

View DNR 2025 spray block maps.

Landowners, land managers and property ownership groups may decide to hire an aerial application business to conduct an aerial spray. The cost is about $80-100 per acre.

For more information, check out the Spongy Moth Resource Center [exit DNR] and view the DNR guide Organizing an Aerial Spray For Forest Pests: Recommendations And Regulations [PDF].

“Slow The Spread” Aerial Treatments

The Wisconsin Department of Agriculture, Trade and Consumer Protection (DATCP) uses aerial spraying every spring and summer, mainly in western Wisconsin, to treat low-level populations in non-quarantined counties as part of the national Slow the Spread program [PDF exit DNR].

• May-early June: A bacterial insecticide is aerially applied to kill young spongy moth caterpillars.
• Late June-July: A mating disruptor is aerially applied to prevent adult moths from mating.

View DATCP 2025 spray block maps [exit DNR].

View DATCP 2025 spray block book maps [PDF exit DNR].