Thanks to last week’s rain, the area of medium to high scab risk for NC wheat currently flowering includes much of the southern Coastal Plain and Tidewater region from Robeson through Sampson and Lenoir counties, with heavier risk farther east. With the relatively dry forecast, however, risk will likely decline in the coming days. To monitor risk, go to the web site www.wheatscab.psu.edu. In the upper left corner, the plus key lets you zoom in. Just above it, clicking on the square allows you to choose the resistance of your wheat variety. Risk level is given for wheat flowering on the date selected at the top.

Apply a scab-targeted fungicide if your wheat is beginning to flower and your scab risk is medium to high. Wheat heads are susceptible to Fusarium infection from early flowering through about 7 days after mid-flowering. Fungicides containing QoIs (strobilurins) should be avoided after flag leaf stage, as they can increase DON (vomitoxin) in a scab epidemic. Miravis Ace, Sphaerex and Prosaro Pro are the most effective in reducing scab and should be applied at early wheat flowering or up to several days later, or about 6 days after full heading in barley.

--Christina Cowger, Small Grains Pathologist, North Carolina State University

The FHB risk forecast model indicates moderate to high risk for the main wheat- producing areas of the state. Wheat growth is primarily in the heading and/or flowering stages, therefore this time is crucial to protect against FHB. Consider making a fungicide application on susceptible varieties if fields in your county are flowering. Check the Wheat Production Guide 2022-2023 https://grains.caes.uga.edu/content/dam/caes-subsite/grains/docs/wheat/… or the 2023 Georgia Pest Management Handbook for FHB fungicide selection. Follow label instructions. Symptoms of frost damage are already showing up in some counties.

--Alfredo Martinez-Espinoza, Professor and Extension Specialist , University of Georgia

NC wheat is mostly at boot to flag leaf stage, with the earliest fields in the south-central part of the state headed but not yet flowering (thanks to Angela Post for observations). FHB risk is estimated for wheat that is at early flowering on that day (www.wheatscab.psu.edu). In south-central NC, risk is currently low; stay tuned, as a rainy period is forecast in the next 10 days. If fungicides for FHB are needed, which is not clear yet, the timing is early to mid-flowering.

--Christina Cowger, Small Grains Pathologist, North Carolina State University

The Fusarium Head Blight Prediction Center provide daily estimates of disease risk for wheat and barley in 35 states. The map displays the probability of severe disease with red and orange areas of the map having the greatest risk. States along the gulf coast are the current focus of the prediction effort because wheat in these areas is likely at vulnerable stages of growth. The risk map is currently showing low risk for most of these areas.

Tips of using the tool: The prediction center uses a wheat growth model to focus the estimates of disease risk on areas where the crop is at or approaching the vulnerable stages of growth for Fusarium infection. Areas in the central and eastern US where the crop is too young, or is already approaching harvest are displayed as a gray color on the map.

The tool shows the disease risk for susceptible wheat varieties for today’s date. You can select earlier assessment dates by clicking on the calendar menu at the top of the risk map. Use the menu button on the upper left to active risk maps for wheat varieties with moderate levels of genetic resistance to Fusarium head blight.

Risk maps based on 2, 4 or 6 days of forecasted weather can help users anticipate future trends in disease risk. These maps are available by selecting the 2d, 4d and 6d buttons to the right of the calendar menu.

--Erick DeWolf, Plant Pathologist, Kansas State University

In most of the southern part of the state, wheat is generally at late booth and/or early heading, but cold temperatures have slowed the crop down some. The effect of recent freezing temperatures remains to be seen. This is especially true in the northern part of the state. Several incidences of powdery mildew have been reported. The FHB risk forecast tool is currently showing “low risk”. However, with rising temperatures, projected rainfall, and the crop soon reaching critical stages for FHB infection, there is a need for continued vigilance. For the northwest part of the state, wheat growth stage is at early booth.

--Alfredo Martinez-Espinoza, Professor and Extension Specialist , University of Georgia

With rain and warm temperatures in the forecast, risk to scab is moderate in headed and flowering wheat; however, farmers are probably trying to decide whether or not to put anymore money in the crop after the freeze on Sunday/Monday. Lots of wheat in the state was at boot or later and temperatures got down in the upper 20s across wheat areas. We will know the extent of the damage in the coming week or two.

--Trey Price, Associate Professor, Agronomic Crop Pathology, LSU AgCenter

As of March 6, 2023, wheat is at flag leaf emergence and /or early boot stage in some areas of South Georgia, which is ahead compared to other growing seasons. Early incidences of leaf rust have been documented. The FHB risk forecast tool is currently showing medium risk (with spotty high risk) in the Southwest part of the state. Remain vigilant as the crop will soon reach critical stages for FHB infection in this main wheat producing area of the state. For the northwest part of the state, growth stage is at/or nearing stem elongation.

--Alfredo Martinez-Espinoza, Professor and Extension Specialist , University of Georgia

Although the map shows moderate risk at the moment, the majority of our crop is not flowering. Weather does not look conducive for scab over the next several days. Wheat stages in most varieties range from jointing to boot with a few heading in the southernmost part of the state. The condition of the crop is fair to good. We have seen a lot of herbicide and fertilizer injury up to this point…no rust yet.

--Trey Price, Associate Professor, Agronomic Crop Pathology, LSU AgCenter

The Fusarium Head Blight Prediction Center is active for the 2023 growing season. These tools provide daily estimates of disease risk for wheat and barley in 35 states. The risk map is currently showing areas of moderate and high risk in the Southern US. Growers in these areas should consult with local University Extension or other advisors to evaluate the need for fungicide applications.

Tips of using the tool: The tool shows the disease risk for susceptible wheat varieties for todays date. You can select earlier assessment dates by clicking on the calendar menu at the top of the risk map. Use the menu button on the upper left to active risk maps for wheat varieties with other levels of genetic resistance to Fusarium head blight.

Risk maps based on 2, 4 or 6 days of forecasted weather can help users anticipate future trends in disease risk. These maps are available by selecting the 2d, 4d and 6d buttons to the right of the calendar menu.

--Erick DeWolf, Plant Pathologist, Kansas State University

Scab risk remains moderate to high for several areas of the state. The areas of greatest concern are east of the Missouri River, northwest ND, and northeast ND. Sporadic rain storms and long dew periods will likely keep risk elevated for the northern third of ND.

--Andrew Friskop, Associate Professor and Cereal Extension Pathologist, North Dakota State University