Potato Late Blight and Early Blight Fungicide Intervals

The page links listed below use site-specific hourly weather observations and forecasts to estimate severity and management timing for potato late blight and early blight. Updates will resume in June 2024.

Weather data from AgEye Weather, Sean D. Birkel, Maine Climate Office,
Potato site assistance by G.W. Koehler, UMaine Extension.

Model calculations, design, web posting, and updates by AgRadar, Glen W. Koehler.

Liaison to Maine Potato Board:  Andrew Plant.

Late blight spray intervals based on “Potato Facts: Late Blight Prediction in Maine”, Steven B. Johnson, 2005.  University of Maine Cooperative Extension Bulletin #2418.

Early blight P-values based on “Comparison of forecasting methods for control of potato early blight in Wisconsin” (PDF).  J. W. Pscheidt, and W.R. Stevenson, 1986.  Plant Disease 70:915-920.