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

This past week's hot and humid weather continues to be forecasted for the next five to seven days. Both the National FHB Risk model as well as the NDSU Small Grain Disease Forecasting Model are, and will likely continue, to indicate moderate to high risk for for spring wheat varieties that are rated as very susceptible and susceptible to Fusarium head blight varieties and moderate risk for the spring wheat varieties that are rated as moderately susceptible and moderately resistant across Minnesota and eastern North Dakota.

Meanwhile, there are a few confirmed reports of leaf rust in wheat and crown rust in oats. I suspect that most oat cares are past the window of a fungicide application. If, however, you find your combine turn an orange/brown color during harvest a fungicide would have been an input with a high return in investment. And while hindsight might be the rear end of a cow, remember it for next year's oat crop.

Bacterial leaf streak (BLS) is starting to show in barley and wheat. The easiest way to confirm BLS is to look for the disease when there is still dew on the leaves. If you suspect BLS lesions, simply out your finger behind the leaf and pull the leaf over your finger BLS lesions will almost be transparent and you can see your finger through the leaf tissue. Understand that fungicides do not control BLS and that you can find BLS in field treated with a fungicide.

Finally, a fourth flight if armyworm into NW Minnesota was reported by Dave Grafstrom at the Magnusson Research Farm near Roseau. With the recent storms there is now plenty of lodged grain that would be very attractive to armyworms. If you see feeding on leaves, check not just for grasshoppers and armyworms, especially in those areas that have lodged.

--Jochum Wiersma, Small Grains Specialist, University of Minnesota

Andrew Friskop, Extension Plant Pathologist at NDSU, shared my concern that the risk models were underestimating the risk of FHB last week. Since the weekend the models have started to trend towards moderate to high risk across much of North Dakota and Northwest Minnesota. Below are his thoughts and my two cents about the current risk situation, a summary of the efficacy of the different fungicides, and some thoughts about if and when to spray fungicides in lodged grain.

Risk Models: This past weekend’s weather for most of the state presented conditions of high humidity, rain, and prolonged dews. These three factors greatly contribute to scab risk and now an elevated scab risk exists for small grains (click here to see the most recent maps). According to the NDSU Small Grain Disease Forecasting Model, the greatest scab risk exists for spring wheat varieties that are rated as very susceptible and susceptible to Fusarium head blight varieties. This includes varieties like AP Murdock, SY Longmire, WB 9479, and WB9590. However, there is still a moderate risk for the spring wheat varieties that are rated as moderately susceptible and moderately resistant in parts of North Dakota (and Minnesota).

When looking at the immediate forecast, high humidity levels will be sporadic amongst the days, yet prolonged morning dews are still likely to occur at least a couple times this week. Given this past weekend’s weather and the forecast, scab risk will likely remain elevated for this week.

Fungicide Efficacy: There are several labeled fungicides that provide *good* scab suppression of scab. These include Caramba®, Proline®, Prosaro®, Prosaro Pro®, Miravis Ace®, and Sphaerex®. Fungicides with the sole active ingredient of tebuconazole are rated as *fair*. The active ingredient propiconazole has *poor* efficacy on scab. To put this in terms of percentage reduction of scab and deoxynivalenol (DON/VOM), *good* fungicides provide about 45-60% suppression, *fair* fungicides may only offer 20-25% suppression, and *poor* fungicides provide only about 10% suppression. Understand that tank mixing fungicides does not mean that the efficacy of the tank mix is the sum of both products. In other words, adding tebuconazole to Caramba does not increase the level suppression of scab to 80% or more. Finally, remember that the premixes that do contain tebuconazole are to create a product that provides good to excellent control of other fungal pathogens, including tan spot an d leaf rust.

--Jochum Wiersma, Small Grains Specialist, University of Minnesota