Most of the winter wheat in South Dakota is now at flowering. The predicted FHB risk continues to be low due to dry and hot conditions currently being experienced in the state. A fungicide for wheat that is at flowing would not be necessary at this time. However, it is advisable to keep checking the predicted FHB risk until wheat has completed the flowering to determine the need of a fungicide.

--Emmanuel Byamukama, Assistant Professor and Plant Pathology Extension Specialist, South Dakota State University

Head scab risk has been low across Michigan, likely driven by the exceptionally dry conditions experienced across most of the state. Flowering in our head scab trials in central Michigan (East Lansing) began May 27th. It should be remembered that best fungicide timing for head scab control occurs from flowering (10.5.1) through seven days post the beginning of flowering. Fungicides applied at this time will also assist with protection of the flag leaf and foliage from late season diseases.

--Martin Chilvers, Associate Professor, Field Crop Pathology, Michigan State University

Winter wheat in New York began flowering this week and much acreage was sprayed with Caramba, Prosaro, or Miravis Ace. There is an application window of approximately 7 days from the beginning of flowering in which reasonable FHB and DON suppression can be expected from these fungicides. The risk of FHB infection in winter wheat has increased in some areas of New York over the last few days. Check the Fusarium Risk Assessment Tool (www.wheatscab.psu.edu) and your local weather forecast frequently as your winter wheat crop approaches flowering.

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

Scab infection risk is growing across the state, but especially in the West and North for all resistance classes of wheat. If your wheat in these areas is heading and approaching flowering, stay alert and consider a fungicide application. Caramba, Prosaro and Miravis Ace give good control of most leaf and head diseases, in addition to suppressing scab. Spray nozzles should be angled at 30° down from horizontal, toward the grain heads, using forward- and backward mounted nozzles or nozzles with a two directional spray, such as Twinjet nozzles.

Continue to visit wheatscab.psu.edu to use the Fusarium Head Blight Prediction Center for estimating your crop’s scab risk.

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

Flowering is all 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 high in these areas and so FHB fungicides (Prosaro/ Miravis-Ace/ Caramba) should be applied here. For most parts, wheat is now in the grain filling stage and should be ready for harvesting in the next couple of weeks. For most parts of the flowering season, we stayed relatively dry, and so far, we have not observed symptom development in terms of bleached spikelets. However, with the recent rains DON content of grains may escalate. It is advisable to get the DON content of the harvested grain analyzed before taking it to the market.

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

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

Winter wheat in South Dakota has started flowering, which is also a period when Fusarium head blight (FHB) starts to develop. FHB can cause significant grain yield loss through reduced grain weight and poor quality due to accumulation of mycotoxins mainly deoxynivalenol (DON). The only in-season FHB management practice is by applying a fungicide when the risk for FHB is moderate to high. The timing of the fungicide is crucial in order to maximize protection against FHB. The fungicide needs to be applied at the flowering time, if the risk for FHB is moderate or high. Currently the FHB prediction tool is showing low to high for risk depending on the FHB resistance in the variety planted. Some areas in the state are relatively dry hence the low FHB risk in these areas. However, the FHB risk is likely to change as weather changes. It is advisable to keep checking the predicted FHB risk until wheat has completed the flowering (about 6 days prior to flowering and 6 days after flowering) to be out of danger for FHB. Best fungicides to apply to manage FHB include Prosaro, Miravis Ace, Caramaba.

--Emmanuel Byamukama, Assistant Professor and Plant Pathology Extension Specialist, South Dakota State University

Welcome to the 2021 Fusarium Head Blight Prediction Center. The Prediction Center was renovated this past year and you may need to refresh your web browser to enjoy some of the new features. Please take a few minutes to familiarize yourself with the locations of help documents (“?” Button), assessment date selection calendar, and model selection tools (menu button in the upper left).

The Prediction Center is currently focused on an KS, NE, MI, NY, and WI. Wheat in parts of these states likely at or approaching the flowering stages of growth when the crop is most vulnerable for infection by the Fusarium fungus. Currently, the risk maps indicate the risk is low east of the Mississippi river. However, recent rainy and humid weather in the Great Plains has increased the risk of disease in areas of KS, NE and parts of WI. Growers in these areas should check the growth stage of their crop and consult local advisors for additional information about the risk of disease in their area.

--Erick DeWolf, Plant Pathologist, Kansas State University

Much of the winter wheat in New York will begin flowering (emergence of yellow anthers on heads) over the next week. The DMI (FRAC Group 3) containing fungicides Caramba, Prosaro, or Miravis Ace (latter includes a FRAC Group 7 fungicide) are the most effective fungicides for suppression of FHB and DON contamination when applied at flowering. A flowering application of these fungicide products should be based on Fusarium head blight (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 from the beginning of flowering in which reasonable FHB and DON suppression can be expected. Severe powdery mildew has been observed in some mildew-susceptible varieties. Risk of FHB infection has remained low primarily because of low temperatures which could change over the next several days. Check the Fusarium Risk Assessment Tool (www.wheatscab.psu.edu) and your local weather forecast frequently as your winter wheat crop approaches heading and flowering.

Winter malting barley is generally beyond growth stages at which a foliar fungicide application should be considered

Be sure to join us for Cornell’s Virtual Small Grains Management Field Day on June 3 at 10 AM EDT (https://blogs.cornell.edu/ccefieldcropnews/2021/05/19/2021-small-grains…).

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

Pockets of higher scab infection risk exist in Western and Northern PA as we wrap up May. Those growers who are working with highly susceptible varieties that are about to flower should consider a fungicide application on those crops. Generally, recent dry weather has driven down risk levels for most varieties across the state, but central and Northern growers should keep an eye on their risk map as rain-generating weather fronts become more frequent.

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

Predicted Risk for Head Scab Continues to be Low Across Ohio. Although it has rained over the last few days, temperatures have dropped into the upper 50s and lower 60s, with nighttime temperatures in the mid-to-upper 40s in some places. Cold temperatures between anthesis and early grain fill usually reduce the risk for scab, as the disease develops best under warm, wet, or humid conditions. However, do keep your eyes on the weather and the forecasting system as the crop continues to go through the anthesis growth stage over the next few days, particularly in the northern third of the state. The forecast is for warmer temperatures and isolated showers over the Memorial Day weekend and into next week (the week of May 31). Late-developing fields may still be at risk for head scab as temperatures increase, particularly if it stays wet and humid. You may need to consider applying Prosaro, Caramba, or Miravis Ace, but remember, these fungicides are most effective against head scab when th ey are applied at or a few days after anthesis.

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