Wheat and barley in most of Pennsylvania, Maryland, Delaware and New Jersey plus eastern New York are at medium to high risk of developing head scab during flowering. "Our current weather forecast includes a few more days of wet, mild weather," says Penn State Extension Agronomist Paul Craig.
Warm weather and high humidity at flowering puts the risk of Fusarium head blight infection very high, he warns. Pathologists are suggesting that wheat no-tilled into fields with high levels of corn residues should be priorities for treatment.
Penn State's web-based scab risk assessment tool is a disease forecasting tool that can be helpful in making control decisions. It's part of the "scab alert" system set up last year by the U.S. Wheat and Barley Scab Initiative. It covers the whole nation, but allows you to localize risk predictions
Here's the link: http://www.wheatscab.psu.edu/riskTool_2011.html. With a few clicks, you can get a prediction of the cereal crop risk level for your area over the next seven days.
Be prepared to spray a fungicide on fields that are at medium to high risk at flowering, suggests Craig. Caramba, Proline and Prosaro are effective on scab and give control of most leaf diseases and glume blotch.
But remember, sprays applied before flowering will not provide significant suppression of scab or toxin production. Also, the labels of these products do not allow spraying after mid-flowering. And, there is a 30-day to harvest restriction.
Craig adds that in Pennsylvania, some suppliers are out of the fungicide Prosaro. Caramba is becoming short. As a substitute, growers can tank mix Proline and Folicur at a rate of 3 ounces of Proline plus 3 ounces of Folicur per acre.