USA NPN National Phenology Network

Taking the Pulse of Our Planet

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Eastern tent caterpillar consuming a leaf.

Eastern Tent Caterpillars are a native pest well known for the silk tents built by the caterpillars in deciduous trees.

Image credit:
Tom Potterfield (Wikipedia)

Eastern tent caterpillar Forecast

Eastern Tent Caterpillars are a native moth and while they can defoliate trees, the trees rarely die as a consequence.

Eastern tent caterpillar current day forecast

Eastern Tent Caterpillar Current Day Forecast.

Eastern tent caterpillar six day forecast

Eastern Tent Caterpillar 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

Eastern tent caterpillars (Malacosoma americanum) overwinter as an egg mass. After hatching, the caterpillars work together to build their silken tent, which they use for shelter during hot or rainy weather. After four to six weeks of feeding on leaves they pupate and the adult moths emerge three weeks later. Eastern tent caterpillar population size varies year to year, with large outbreaks every few years. This species is native to North America.

Cluster of eastern tent caterpillars. Photo credit: JR Carmichael.Caterpillar Forecast

Knowing the timing of caterpillar emergence can shed light on food availability for birds as well as guide control measures. For specific information on preferred treatment options in your region, we recommend contacting your local extension agent.  Additional resources are available through UMass Extension.



GDD threshold

Base temp

Start date

GDD method

Model origin


Caterpillar emergence



March 1

Simple average


Cornell Cooperative Extension

More information on map development and re-use policy.

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