Head Scab Risk has Increased Across Ohio.

Due largely to rainfall, high relative humidity, and warmer temperatures over the last several days, the risk for head scab is now moderate across most of the state of Ohio, and high across the south. The risk is low in NW Ohio. This would be the time to consider applying a fungicide to control head scab and reduce the risk of grain contamination with mycotoxins as fields reach anthesis in the northern third of the state. Even fields in the lower half of the state that flowered 5-7 days ago could benefit from a fungicide application. Most of the recommended fungicides for FHB management provide similar levels of FHB and vomitoxin suppression when applied between early anthesis (Feekes 10.5.1) and early grain-fill (up to six day after early anthesis).

The recommended, and most effective, fungicides for scab and vomitoxin control are Miravis Ace, Prosaro, Caramba, Proline, Sphaerex, and Prosaro Pro. These products provide comparable levels of scab and vomitoxin suppression when applied at early anthesis or shortly thereafter. Applications made to wheat at early or full head emergence (between Feekes 10.3 and 10.5) may also suppress scab (compared to no fungicide at all), but tend to be considerably less effective against vomitoxin. Several of these fungicides are also very effective against leaf diseases, which are also on the increase in some areas. Please read product labels carefully before making an application, in particular, pay close attention to the preharvest intervals.

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

Wheat is, or will soon be, flowering (Feekes growth stage 10.5.1) in parts of central and northern Ohio. Feekes 10.5.1 is the growth stage at which the crop is most susceptible to infection by the fungus that causes head scab and produces vomitoxin. However, most fields across the state are currently at low risk for head scab. This is likely because of the relatively low temperatures we have experienced over the last few days. The map indicates that the risk for head scab development is low (mostly yellow) in fields flowering today, May 26, and assessments based on 2-6 days of forecasted weather suggest that the risk will continue to be low in the western 2/3 of the state where most of the wheat is grown and moderate (specks of orange) in a few areas out east. Continue to look at the tool as more fields reach anthesis; the risk could change quickly as it warms up, particularly if the warmer weather is accompanied by high relative humidity and/or frequent rainfall.

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

In Illinois, wheat will start flowering within the next few days in much of the state. We are currently experiencing temperatures in the 90s after a long period of cool wet weather. Due to these temperature swings, it may be harder than usual to predict when flowering will begin. Wheat fields should be monitored every other day for flowering and a fungicide should be applied when most of the heads are at the early flowering stage or as soon as possible afterward.

--Jessica Rutkoski, Assistant Professor, University of Illinois at Urbana-Champaign

Depending on the location and the variety maturity, wheat in Kentucky is at Feekes growth stage 10.51 (early anthesis) or beyond. Most wheat fields in the most southern areas of Kentucky would likely have been at Feekes 10.51 last week or before. Many wheat fields that are closer to southern Indiana or southern Illinois would likely be at the Feekes 10.51 stage now or soon will be. For most of the state, FHB risk is low, but there are some areas that show medium to high risk. Many of these areas showing risk are those in which wheat likely was at Feekes 10.51 last week. The risk is likely due to weather that was received last week (rainy and cooler conditions). Within the next few days, the risk map model will likely account for the very hot and sunny days that currently are occurring, which will reduce the risk of FHB greatly.

--Dr. Carl A. Bradley, Professor and Extension Specialist, University of Kentucky

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

Several wheat fields in Kentucky currently are at the early anthesis stage (Feekes growth stage 10.51) or beyond that stage. Currently, the FHB risk map is showing a medium risk for FHB in some areas of Kentucky. With rainfall in the forecast in the upcoming days, this risk may increase and encompass a larger geography. Because of rainfall, soil is saturated in several fields, making it difficult for ground sprayers to apply fungicides. It is important to note that multi-state research trials have shown that effective fungicides registered for FHB control in wheat have been effective in reducing FHB and the associated mycotoxin DON when applied up to 7 days after the early anthesis stage. Please read all fungicide labels before making any applications to ensure that your crop is still at a stage where fungicides can be applied.

--Dr. Carl A. Bradley, Professor and Extension Specialist, University of Kentucky

Wheat in the Northern part of the state has started to flower this week, whereas wheat in the central part of the state has just finished flowering. Warm, wet weather will continue to elevate FHB risk in flowering wheat, and a fungicide application of Caramba, Prosaro, Proline, or Miravis Ace are suggested at this time. Applications are most efficacious when made following label directions between the start of flowering and 5 days after this point in time. Flowering is defined as the point in time when 50% of main tillers have started to push anthers. Do not apply products containing strobilurins for FHB management.

Wheat in the southern part of the state should now be showing symptoms and signs of FHB if severe infection occurred (bleached heads/portions or heads/spikelets with salmon colored growth). Recent surveys indicate that overall FHB levels are likely low in this part of the state. The central part of Illinois however, was under high risk across wheat resistance levels during the critical flowering period and should be monitored closely over the coming days. Symptoms of FHB will be most observable 18-24 days after flowering. If severe FHB is detected, you should be prepared to take measures to remove contaminated grain. These include increasing combine fan speeds and openings to blow out lightweight, FHB-infested grain, harvesting infected fields as early as possible (and preferably first) and if possible, storing grain from infested fields separately from quality grain. Ensure that grain is dried (15% optimal) to minimize continued growth of pathogen and DON accumulation in storage.

-- Nathan Kleczewski Ph.D., University of Illinois, Research Assistant Professor and Extension Specialist

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

 

According to the head scab forecasting system (http://www.wheatscab.psu.edu/), the risk for head scab, and consequently , vomitoxin contamination of grain is current high across the state for wheat flowering today. I fact, the risk for scab has been high throughout the week due to the fact that it has been wet and warm. Most of the wheat in northern OH it either at or will soon be at the critical anthesis or flowering growth stage when infection by the scab fungus typically occurs. There is more rain and warm weather in the forecast, meaning that the risk will likely continue to be high as more fields in the northern third of the state reach anthesis. Plan to apply either Prosaro, Caramba, or Miravis Ace at or within the first 4-5 days after anthesis. This will reduce scab and vomitoxin by 50% of more.

Click on the link below to learn how to interpret the foresting system and identify the anthesis growth stage. https://agcrops.osu.edu/newsletter/corn-newsletter/2020-15/using-forecas...
--Pierce Paul, Extension Plant Pathologist, Ohio State University
For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu
For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to http://www.scabusa.org

High scab risk is predicted for all wheat of all resistance levels across much of the state according to the current risk model. Additionally, many varieties are moving into flowering or are currently flowering in much of the state with high risk. Now is the time to consider a fungicide application for fields that are flowering or are soon to be. With rains predicted in the coming days, it is important to remember that the optimal time for a fungicide application is at or within 5 days of flowering, so find the window to apply an effective triazole or triazole + SDHI fungicide when possible. Be sure to keep in mind the rainfast period when applying during these windows. DO NOT apply a strobilurin-containing fungicide as these fungicides can increase mycotoxin levels in the grain. Always read and follow label instructions when applying fungicides.

-- Kaitlyn Bissonnette, University of Missouri, State Field Crop Plant Pathologist

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org

Wheat in the southern part of Illinois is currently flowering to past flowering. Wheat in the central part of the state is approaching heading in many fields. With warmer temperatures forecast I expect many fields in the central part of the state to flower next week. Rains are forecast during this time as well, which may elevate risk for FHB in wheat flowering during this period. Replicated research indicates all suggested fungicides for suppressing FHB are most efficacious in suppressing vomitoxin when applied between FGS 10.5.1 through 5 days after 10.5.1. FGS 10.5.1 is defined as the point where 50% of the main tillers have started to flower in a field. Symptoms of FHB are typically most pronounced 18-24 days after flowering.

Suggested fungicide products for suppressing FHB and vomitoxin include Prosaro, Caramba, Miravis Ace, and Proline (if following with vegetables). Ensure that all label directions are being followed to ensure proper application and to ensure optimal performance. Do not apply fungicides that contain a strobilurin (FRAC group 11) as these have been associated with enhanced DON in replicated research trials. Continue to monitor your fields and the FHB prediction center as you approach the most critical times for applying in season fungicides for FHB.

-- Nathan Kleczewski Ph.D., University of Illinois, Research Assistant Professor and Extension Specialist

For more details, go to the FHB Risk assessment tool at http://www.wheatscab.psu.edu

For the latest news and updates from the U.S. Wheat & Barley Scab Initiative, go to https://www.scabusa.org