Delaware Department of

Forest Health

Forest Health MonitoringForest Health Monitoring (Diseases and Pests)

The Delaware Forest Service strives to ensure that Delaware’s rural and urban forests are vigorous and as free from pests as possible. Our foresters diagnose forest pest problems and recommend treatments to landowners and homeowners. Our Forest Health Specialist monitors forest pest populations through annual aerial surveys and a statewide network of permanent plots to help detect trends in the long-term health of our forests.


Our forests are continuously threatened by a variety of harmful pests. Early detection is key to keeping these pests under control. You can help us keep our forests healthy by reporting any sign of the pests listed below:

Increase in Spongy (Gypsy) Moth Activity Detected For 2022
Defoliation predicted for the following May and June is as follows:

1-200 egg mass per acre (EM/ac) Very Light (1-3% of canopy leaves)
201 – 400 EM/ac Light (4-10%)
401 – 600 EM/ac Moderate (11-29%)
601 – 800 EM/ac Severe (30-50%)
801+ EM/ac Very Severe (> 50%)

Forest landowners who suspect they may have enough egg masses per acre to warrant a privately contracted spray may call the Forest Health Specialist at (302) 698-4553 for technical assistance.

Spring 2024 Proposed Spongy Moth Spray Program
Mimic Insect Growth Regulator Fact Sheet

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