Weather and Potato Disease Models
We use gridded hourly NOAA weather data available on AgWeather and VDIFN to run predictive disease severity models for early blight and late blight to give growers the information they need to mitigate disease risk in potato production. Select a location page below for interactive weather and disease severity charts.
Select a weather data location:
Disease model interpretation:
DSVs: Late blight risk can be modeled using disease severity values (DSVs). First, select your nearest weather station. On the chart shown, highlight the date of your last spray and note the cumulative DSVs at that point. Then subtract that number from the most recent cumulative DSV value to get the accumulated DSVs since your last spray. When this value exceeds 18, late blight management action is recommended. You can download each chart by clicking on the menu button on the upper right corner. Visit VDIFN and select the Late Blight model for a statewide map of late blight risk.
P-Days: Early blight risk is elevated after 300 P-Days (physiological days) have accumulated after crop emergence. Early blight management actions are recommended beyond that point. You may need to subtract accumulated P-Days from prior to your specific crop emergence date from the weather station report. Visit VDIFN and select the Early Blight model for a statewide map of P-Days and early blight risk.
More information:
- Visit our Disease Profiles page for more information about common plant diseases afflicting vegetable crops.
- Visit the Vegetable Crop Entomology webpage for more information about common vegetable insect pests and how to manage them.
- Visit AgWeather for access to weather data and degree day models for the upper Midwest, as well as to subscribe to daily weather data emails.
- Visit the Vegetable Disease and Insect Forecasting Network (VDIFN) website for an interactive map-based tool for viewing plant disease and insect pest risk models as well as degree day data for the upper Midwest.
- Use the Wisconsin Irrigation Scheduling Program website for managing irrigation on your farm.