USA NPN National Phenology Network

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Emerald ash borer adult

An invasive pest, emerald ash borer has killed millions of ash trees in the United States.

Image credit:
David Cappaert,

Emerald Ash Borer Forecast

Emerald ash borer is a beetle that causes significant harm to ash trees throughout the eastern United States. 

Emerald ash borer current day forecast

Emerald Ash Borer Current Day Forecast.

Emerald ash borer six day forecast

Emerald Ash Borer 6-Day Forecast.

Pheno Forecast maps predict key life cycle stages in invasive and pest species, to improve management efficacy.  For insect pest species, Pheno Forecasts are based on published growing degree day (GDD) thresholds for key points in species life cycles. These key points typically represent life cycle stages when management actions are most effective. These maps are updated daily and available 6 days in the future.

Help us improve these maps! Our Pheno Forecast map products are still in development, and we seek input on their performance in your area. Give your feedback on the sidebar on the right side of this page.

Species Background

Emerald Ash Borer (Agrilus planipennis) is non-native beetle from Asia which has spread across the eastern United States since 2002. In their larval stage, the beetles destroy the heartwood of ash trees, killing them within a few years. The pest is responsible for the death of hundreds of millions of ash trees.

Adult Forecast

EAB larvae, Photo:Pennsylvania Department of Conservation and Natural Resources - Forestry,

We forecast adult emergence based on growing degree days. Treatments are applied to control for adult beetles on infested trees, to reduce the spread of the pest. Adults lay eggs approximately 14 days after emergence, so treatment is critical in this window. For specific information on preferred treatment options in your region, we recommend contacting your local extension agent.  For more information on treatment guidance, visit Insecticide Options for Protecting Ash Trees from Emerald Ash Borer or Emerald Ash Borer Information Network.


GDD threshold

Base temp

Start date

GDD method

Model origin


Adult emergence

450-1500 oF


January 1

Double sine


Herms et al 2019

More information on map development and re-use policy.

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