Don't Sleep on Head Scab in 2025

Southern Pennsylvania is just past flowering in wheat and is watching its barley ripen. Meanwhile, our northern regions have small grains that are entering flowering or heading now. Don't let your guard down when it comes to small grain diseases, as now is the time to take action on Fusarium head blight (scab) if you haven't already. 

Flowering can occur about 3 to 5 days after heading, depending on variety and weather. Early flowering is the ideal time to spray a product to control head scab. Infection risk levels differ by region, but many parts of the state are in the "high risk" category for infection at this time (Figure 1). Miravis Ace, Prosaro, Prosaro Pro, and Sphaerex all provide very good scab suppression. The Miravis Ace label allows for earlier application than other fungicides, but best results are still achieved when application is timed after full heading in barley and flowering in wheat. If you missed a fungicide spray at flowering, you can still spray up to about six days later and still expect worthwhile efficacy to mitigate scab and mycotoxin production. Follow labels to determine post-harvest interval constraints for the fungicide you choose. Spray nozzles should be angled at 30 degrees down from horizontal, toward the grain heads, using forward- and backward-mounted nozzles or nozzles with a two-directional spray, such as Twinjet nozzles.

Additionally, a fungicide treatment at heading using any of these products will also give you excellent control of most leaf diseases as well. Do not use any of the strobilurins (Quadris, Headline), or strobilurin/triazole (Twinline, Quilt, Stratego) combination products at flowering or later. There is evidence that they may cause an increase in mycotoxin production. 

For helpful information about these and other wheat fungicides, download Fungicide Efficacy for Control of Wheat Diseases. This chart provides details on the best fungicides for each disease, when they may be used, and use rates. 

If your crop is well beyond flowering, the infection risk indicators can help you understand how favorable the environment is for the fungus to spread within the plant if it entered during flowering. While there's not much to be done beyond a week after flowering, it can be helpful to know how high disease pressure was during the time your grain was developing to give some clues as to how concerned you should be for your crop.

You can view your area's risk level at any time by visiting the Fusarium Risk Tool.