European spongy moth (formerly gypsy moth) caterpillars feed on deciduous trees, causing major defoliation and tree mortality. They are considered one of the worst forest pests in the United States.

Spongy Moth Current Day Forecast

Spongy Moth Six-Day Forecast

WHAT ARE PHENO FORECASTS?

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 at the bottom of the page.


SPECIES BACKGROUND

Spongy moth (Lymantria dispar) egg masses hatch in late spring and the caterpillars feed extensively on many types of trees, favoring oaks, birches and poplars.  Spongy moth caterpillars spend the day hidden in leaf litter or under bark, and ascend their tree at night to feed. Spongy moths are native to Europe and Asia. 


Credits: Scott Bauer, USDA Agricultural Research Service via Bugwood.org
Image
A spongy moth caterpillar is seen moving vertically on a partially eaten leaf.

CATERPILLAR FORECAST

We forecast caterpillar emergence based on growing degree days. Certain control measures are most effective when caterpillars have recently emerged from their egg masses. For specific information on preferred treatment options in your region, we recommend contacting your local extension agent. Additional identification and treatment resources are available through USDA APHIS and UMass Extension.


EXPLORE THIS FORECAST

Learn more about this forecast using our visualization tool!

Phenophase

GDD threshold

Base temp

Upper threshold

Start date

GDD method

Model origin

Source

Caterpillar emergence

571oF

37.5oF

104oF

Jan 1

Double sine

PA, WV

Russo et al (1993)

More information on map development and re-use policy.

TRACK THIS SPECIES WITH NATURE'S NOTEBOOK

 

You can help verify this forecast by checking trees for this species and reporting your findings in Nature’s Notebook via the Pest Patrol campaign. Your observations will help scientists better understand when this species is active and susceptible to treatment.

 

Learn more about Pest Patrol

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