USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Pheno Forecast maps estimate the appropriate time to treat insect pests. For example, for emerald ash borer, the maps forecast when to spray pesticide on infested trees to reduce the spread of this pest. 

Image credit:
David Cappaert, Bugwood.org

Pheno Forecasts

The USA-NPN Pheno Forecasts can help you determine when it is time to treat insect pests. 


Emerald Ash Borer 6-Day Forecast.

Pheno Forecast maps show when management actions should be taken for key pest species. These maps are updated daily and are available 6 days in the future.  Pheno Forecasts are based on published growing degree day (GDD) thresholds for points in pest life cycles when management actions are most effective.

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

Find out when to treat your trees for pests

Are you concerned about pests damaging your plants?  These maps will help you determine when your site will reach critical heat accumulation for the detection, management, and treatment of insect pests.  Maps are available via the USA-NPN visualization tool and on the individual species landing pages below. 

Available maps

Apple Maggot
Emerald Ash Borer
Hemlock Woolly Adelgid
Lilac Borer
Winter Moth

More Information 

These forecasts are based on USA-NPN Accumulated Growing Degree Day (AGDD) map products and published GDD thresholds. References for the published thresholds used to generate the forecasts appear on the individual species pages.

These maps are intended to provide a broad-scale prediction regarding when management action may be necessary and are intended to supplement local knowledge. Forecast accuracy may vary locally based on microclimatic variation. In addition, thresholds may perform with variable accuracy across species ranges. For more information about these pests and others, specific to your state, contact your local Cooperative Extension program.

We invite your feedback on the performance of these forecasts at your location. You can help us improve the accuracy of these forecasts by letting us know when pests undergo life cycle stages at your location. You can report observations of hemlock woolly adelgid and lilac borer in Nature's Notebook

Re-use of Maps and Data

Content, maps, and data accessible via usanpn.org are openly and universally available to all users. USA-NPN is not responsible for the content or the use of the data. Content may be re-used and modified with appropriate attribution (e.g., "source: USA National Phenology Network, www.usanpn.org"; see our complete Content Policy). See our Data Use Policy for suggested citation and attribution of the underlying data products.