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:

Spongy Moth (formerly Gypsy Moth)
Defoliation in May and June is predicted by over-wintering “fresh” egg mass densities.
Do not count faded and tattered egg masses from the previous year.

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.

Related Topics:  , , , , , ,