Spongy Moth Pheno Forecast, Contiguous United States, 2016 - Current Year

Pheno Forecast maps predict key life cycle stages in a range of species to improve conservation and management outcomes. 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. We forecast caterpillar emergence in spongy moth (Lymantria dispar) at 571F growing degree days (base 37.5F, upper threshold 104F, start date: January 1, double sine GDD method). Forecasts are available for the current and prior year in the USA-NPN Visualization Tool (https://www.usanpn.org/data/visualizations) and 2016-present through USA-NPN Geo Web Services (available upon request). Spongy moth egg masses hatch in late spring and the caterpillars feed extensively on many types of trees. Certain control measures are most effective when caterpillars have recently emerged from their egg masses.