By: Pierce Paul, OSU Extension
The head scab risk tool can be used to assess the risk of head scab and to help guide fungicide application decisions. Here are a few guidelines for using the system and interpret the output:
1.) Go to the website at www.wheatscab.psu.edu. You will see a map of the United States with some states in green, yellow, red, or gray.
2.) STOP. Before you try to interpret the map, make sure that you select:
- The flowering (anthesis) date for your field,
- Winter wheat (the class of wheat we grow in Ohio), and
- The susceptibility of the variety planted in your field.
3.) Zoom in to Ohio and move the “Counties” slider over to the right to see county lines.
4). Zoom in further to your county and move the “Streets” slider over to the right to see major highways.
5.) Find the approximate location of your field and assess the risk for head scab (*susceptible variety):
- Scab susceptible soft red winter wheat variety planted in my field in Wooster, OH.
- Flowering on May 26, 2020.
*Map is red in the area of my field, meaning that scab risk is high.
6.) Find the approximate location of your field and assess the risk for head scab (**moderately resistant variety):
- Moderately resistant soft red winter wheat variety planted in my field in Wooster, OH.
- Flowering today, May 26.
**Map is green in the area of my field, meaning that scab risk is low.
Continue to use the tool to monitor the risk of head scab over the next several days as more fields in the northern half of the state approach anthesis. If the risk is moderate-high (the map is yellow or red) at the time of flowering, you should consider applying Prosaro, Caramba, or Miravis Ace, at anthesis (flowering) or within the first 4-6 days after flowering. Learn how to identify the flowering or anthesis growth stage here: