Most of the winter wheat has flowered and is entering stages of kernel fill. Scab risk was low and has remained low for susceptible varieties. This is likely attributed to the sporadic rain from pop-up showers and low relative humidity. Some of the heat and water stressed spring wheat is starting to head and the scab risk looks remain low in the coming days. Given the variation in planting dates and growing conditions, we will see a wide range of flowering in spring wheat this year.

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

Winter wheat heads have emerged from the boot nearly everywhere and many are now flowering (yellow anthers visible) in fields across New York State. This is a critical time for making a fungicide spray decision. The fungicide products Caramba, Miravis Ace, Prosaro, Prosaro Plus, and Sphaerex are each labeled on wheat in New York and are effective in suppression of Fusarium head blight (FHB) and deoxynivalenol (DON) mycotoxin contamination. An application of these fungicide products should be based on FHB risk as well as the risks of powdery mildew, rusts, and fungal leaf blotches in the upper canopy based on scouting of individual fields. There is an application window of approximately 7 days starting at beginning of flowering in which reasonable FHB and DON suppression can be expected. Though the calculated risk of FHB infection is currently low due to dry conditions, the risk level may change in following days. Also consider microenvironments near lakes, in river valleys and n ext to woods that tend to have persistent dew, and other fields that have a history of mycotoxin contamination. Check the Fusarium Risk Assessment Tool (www.w.heatscab.psu.edu/ ) and your local weather forecast frequently.

You are invited to attend Cornell’s 35th Annual Small Grains Management Field Day at Fleur De Lis Brewery in Seneca Falls on June 8. Visit https://cals.cornell.edu/2023-small-grains-managment-field-day to view the agenda and pre-register (free)!

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

Flowering is finished across all counties of Maryland now, except for a few late-planted fields in the northern part of MD that may still be flowering. Currently, the risk of FHB is low in these areas and so no fungicide application is needed. For most parts, wheat is now in the grain-filling stage and should be ready for harvesting in the next couple of weeks. We experienced some showers this season, but the temperatures remained low, so symptom development in terms of bleached spikelets is limited especially if the planted variety is resistant. It is advisable to get the DON content of the harvested grain samples analyzed before taking it to the market.

This is the last FHB risk commentary of the season for MD, but feel free to contact me (email: nidhirwt@umd.edu) if you have any questions related to wheat or barley diseases any time of the year! Wish you a plentiful harvest!

--Nidhi Rawat, Small Grains Pathologist, University of Maryland

The FHB risk map is showing moderate to high risk in parts of western Nebraska. There have been significant amounts of rainfall in some areas in the region in recent weeks. In the southwest wheat is flowering or just past flowering. In the Panhandle (northwest), growth stage is at Feekes 9 to boot to just starting to head depending on the location, and therefore it is too early for infections to occur at this time. Growers in the southwest and Panhandle regions of Nebraska should monitor the weather and their wheat fields, especially irrigated fields. Additional precipitation will increase the risk of FHB in these two regions. In the eastern half of the state, wheat is past the flowering growth stage in most fields; it has been too dry in this part of the state, which has kept FHB risk low.

--Stephen Wegulo, Professor/Extension Plant Pathologist, University of Nebraska-Lincoln

Flowering continues in wheat this week across the northern half of the state of Ohio. This is the growth stage as which the crop is most susceptible to infection by Fusarium graminearum, the fungus that cases Fusarium head blight (FHB), also known as head scab. Consequently, questions are being asked about applying a fungicide to control FHB and minimize grain contamination with mycotoxins. However, according to the FHB forecasting system, the risk for head scab development has been low across the state over the past week. This is likely due, at least in part, to the cool, relatively dry conditions we have experienced in most area. The extended forecast suggests that dry (rain-free) conditions will persist over the next week or so. Remember, warm and consistently wet or humid conditions are required for FHB to develop. So, do continue to monitor the weather and use the scab forecasting system to determine if the risk for scab is increasing at the crop flowers in northern, late-plante d fields.

--Pierce Anderson Paul, Extension Plant Pathologist, The Ohio State University

The risk map is currently showing some areas of high to moderate risk for areas of Southeastern and Northwestern Kansas. The wheat in the Southeastern region of the state is now past the flowering and early growth stages of grain development that are most vulnerable to Fusarium head blight. In contrast, the region of Northwestern Kansas that is at high risk is too immature to be at a high risk for disease. Wheat in this area of the state is still at flag leaf emergence through the boot stage of development. Growers in the Northwestern region of the state should be monitoring the situation carefully especially in irrigated fields where the additional moisture has helped preserve yield potential through the dry soil conditions earlier this spring.

--Erick DeWolf, Plant Pathologist, Kansas State University

Wheat in the Eastern shore and the Southern part of the Western shore of Maryland has finished flowering, except for a few late-planted fields. Up in the Northwestern counties of the state (Frederick, Howard, Carroll, Harford) also wheat is either flowering currently or is already past flowering. In spite of the sporadic rain events, the risk for FHB is low currently, mostly because of the cool spring season that we are experiencing. We are observing some powdery mildew, rusts, and Barley Yellow Dwarf Virus (BYDV) in some of our test plots at Wye right now. If you are noticing these foliar diseases and thinking of controlling them, it is important to remember that Strobulurin-containing fungicides should not be applied at this stage even for controlling these. BYDV cannot be controlled by fungicides as it is a viral disease. The FHB fungicides (Prosaro/ Miravis-Ace/ Sphaerex/ Prosaro-Pro) will be able to control the other fungal foliar diseases as well.

--Nidhi Rawat, Small Grains Pathologist, University of Maryland

Wheat in Maryland is mostly either flowering or finishing up flowering. As I always say, genetic resistance goes a long way in FHB management. If you planted a resistant variety the FHB risk is minimal at this point, whereas if you have a susceptible variety, the risk is catching up. So, if your wheat is flowering currently, and you have a susceptible variety, it is suggested to consider fungicide application for FHB management. The recommended stage for application of fungicides on wheat is at flowering (50% of the main tillers showing yellow anthers) or within 4-5 days of that. The fungicides effective for FHB are Miravis-Ace/ Prosaro/ Prosaro-Pro/ Sphaerex). These fungicides do not need to be tank mixed with another product for spraying. The fungicide products should be applied at the full rate recommended by the manufacturers. Strobilurin containing fungicides should not be sprayed at this stage. If your wheat is past flowering already, you don’t need to spray these fungicides. However, if it is not flowering yet, it's a good idea to keep a watch on the weather and the FHB risk.

--Nidhi Rawat, Small Grains Pathologist, University of Maryland

Scab infection risk is growing across the state for all resistance classes of wheat and barley, but it is variable by location. If your barley or wheat in high risk areas is heading and approaching flowering, stay alert and consider a fungicide application. Caramba, Miravis Ace, Prosaro, Prosaro Pro, and Sphaerex all provide very good scab suppression. The Miravis Ace label allows for earlier application than Caramba or Prosaro, but best results are still achieved when application is timed after full heading in barley and flowering in wheat. If weather conditions prevent fungicide application at ideal timing, an application as soon as conditions allow will still be quite effective in reducing scab and DON production. Follow labels to determine post-harvest interval constraints for the fungicide you choose.

--Alyssa A. Collins, Associate Professor, Plant Pathology and Environmental Microbiology, The Pennsylvania State University

With the recent showers in the state, the risk of Fusarium Head Blight has increased slightly. However, the low temperatures have prevented the risk from being too high presently. Wheat is anywhere from heading to flowering to the end of flowering in the state right now. If you have planted an FHB-resistant variety, you should be okay to skip the fungicide sprays currently. Growers who planted susceptible wheat with their wheat flowering or are within a window of 4-5 days of flowering are advised to spray head scab fungicides: Prosaro/ Prosaro-Pro/ Miravis-Ace/ Sphaerex. These fungicides do not need to be tank mixed with another product for spraying and should be applied at the full rate recommended by the manufacturers. Strobilurin-containing fungicides should not be sprayed at this stage. With more rain coming, keep an eye on the FHB risk if your wheat is not flowering yet.

--Nidhi Rawat, Small Grains Pathologist, University of Maryland