Michigan potato late blight forecast – June 12, 2018

Potato late blight risk is moderate in southwest and central Michigan growing regions.

Figure 1. June 12, 2018 – Michigan late blight forecast based on accumulation of disease severity values (DSVs). Yellow pins on the map indicate medium risk areas and currently include southwest and central regions. Green pins indicate low risk areas. Image provided by Jaime Willbur, MSU Extension.
Figure 1. June 12, 2018 – Michigan late blight forecast based on accumulation of disease severity values (DSVs). Yellow pins on the map indicate medium risk areas and currently include southwest and central regions. Green pins indicate low risk areas.

The Michigan Late Blight Forecast Tool is currently calculating 2018 risk predictions. Due to the warm, wet weather this season, late blight risk has risen to moderate levels in some areas (Fig. 1).

Late blight is caused by Phytophthora infestans, which favors 60-80 degrees Fahrenheit temperatures, high humidity and frequent rainfall. This online forecasting tool calculates disease severity values (DSVs) based on the duration of temperature and relative humidity conditions that are favorable for disease development.

Accumulated DSVs are used to determine the local late blight risk level, indicated by the color of the map marker pins:

Low risk
(Green)

Medium risk
(Yellow)

High risk
(Orange)

Late blight detected within 2-5 miles
(Purple/Pink)

Late blight detected within 1 mile
(Red)

This tool was developed by Baker et al. 2002 and weather data used in this model is provided by the Michigan State University Enviroweather.

Please visit the MSU Potato Disease website for more information. Answers to frequently asked questions about this forecast tool are available.


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