Fusarium head blight risk for spring wheat varieties with a rating of 6 or worse will be high across much of the state through the end of the week. The heart of the Red River Valley is the only area with a low to moderate risk. A marked difference in the risk of infection exists between highly susceptible and moderately resistant varieties.

More info at: https://blog-crop-news.extension.umn.edu/2024/06/small-grains-disease-a…

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

Fusarium head blight risk continues to remain low for most of the state. If a very susceptible variety was grown (FHB score of 7 or higher in HRSW Variety Guide), moderate to high risk exists in northeast North Dakota (Figure 1). Most of the state received rain over the past couple days, and several areas of the state will receive more rain in the coming days. The precipitation in combination with higher relative humidity values projected next week will likely increase scab risk in the state. Based on field reports, the earliest planted spring wheat is at boot to heading stages with the late planted wheat in the early leaf stages. Given the large variation in growth stages, make sure to pay attention to the weather and scab risk as the barley crop starts to head and the spring wheat and durum crop enter heading to flowering.

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

The focus of the wheat scab (Fusarium head blight) prediction effort is currently on SD, MN and ND where wheat is approaching or already at the heading and flowering stages of growth that are critical to the development of Fusarium head blight. The risk maps are currently estimating a low risk of severe disease in these regions, but growers should monitor conditions carefully for extended periods of high relative humidity that favor disease development.

Below are a few tips for using the web-based tools: The website 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 view risk maps for wheat varieties with other levels of genetic resistance to Fusarium head blight. This menu also provides options for viewing additional map features or focusing on just areas with a high density of wheat production.

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.

You can activate graphs of recent weather and trends in disease risk by clicking on the base risk map. The bottom graph panel displays the disease risk for wheat varieties with different levels of genetic susceptibility to Fusarium head blight. The top graph panel displays trends in relative humidity that are conducive for disease development.S

--Erick DeWolf, Plant Pathologist, Kansas State University

Winter barley fields in New York are past the stage for fungicide treatment, and growers are getting ready for harvest in a couple of weeks. This is a good time to assess Fusarium head blight (FHB) symptoms to anticipate issues of mycotoxin contamination in grain. Barley leaf rust, powdery mildew, scald, yellow dwarf, and Stagonospora nodorum blotch have been observed in some fields, generally at low levels.

Winter wheat continues to develop ahead of most years. Harvest is projected to begin in earliest July. Most, but not all, wheat fields are past the stage when fungicide application is effective. There is an application window of approximately 7 days from the start of flowering of wheat in which reasonable FHB and DON suppression can be expected from application of fungicide products Miravis Ace, Prosaro, Prosaro Plus, or Sphaerex. The calculated risk of FHB infection currently ranges from low to high in wheat growing regions of New York, but a drying trend is expected for the next week. Be sure to check the Fusarium Risk Assessment Tool (www.wheatscab.psu.edu) and your local weather forecast frequently. Kernel soft dough stage (approximately three weeks after flowering) is an excellent time to assess wheat for symptoms of FHB and to anticipate issues of mycotoxin contamination in grain. Stripe rust has been observed in a broad area of western New York and the Finger Lakes. Powder y mildew has been more severe than usual in some varieties this season.

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

Most winter wheat fields in New York have heads fully emerged from the boot, and plants in a significant number of fields have initiated flowering (yellow anthers visible). This is a critical time for making a fungicide spray decision. The fungicide products 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 beginning at start of flowering of wheat in which reasonable FHB and DON suppression can be expected. The calculated risk of FHB infection is currently high for wheat flowering today in several wheat growing regions of New York. Of course, the risk level may change in followi ng days. Check the Fusarium Risk Assessment Tool (www.wheatscab.psu.edu) and your local weather forecast frequently.

The presence of stripe rust, a potentially yield-limiting disease, in your field or vicinity is an added factor in considering a flowering-timed fungicide spray this year. The fungicides mentioned above are effective against stripe rust. Stripe rust has been confirmed in Genesee, Seneca, and Tompkins Counties this week and I suspect it is much more widespread. I urge wheat growers to scout their fields for stripe rust and to report occurrences to their field crops extension educator.

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

The head scab model is currently showing low risk across most of Michigan, however this may change with predicted moisture.

Stripe rust has been detected in several counties across Michigan, and growers are urged to scout fields. Stripe rust can develop quickly and result in significant yield loss. Be sure to scout your fields and be aware of disease pressure in your area. The goal is to keep the flag leaf as free of disease as possible throughout the flowering and grain-fill periods. To achieve this, a fungicide may be warranted during or soon after the flag leaf stage, particularly when a fast-moving disease such as stripe rust is present. If stripe rust is detected in your fields and there is still some time before a head scab fungicide application, a fungicide application now may be warranted. There are plenty of fungicide products that do and excellent job of managing stripe rust, for the complete list, see our multi-state fungicide efficacy guide: https://cropprotectionnetwork.org/publications/fungicide-efficacy-for-c….

If the crop is very close to flowering a fungicide applied at flowering to reduce risk of head scab and DON will also do a great job at providing protection of the flag leaf.

Winter wheat development in Michigan ranges from flag leaf to head emergence, with flowering expected within the next week or two. Leaf diseases have been minimal to date, with only limited reports of powdery mildew, Septoria blotch and leaf rust. To date stripe rust has not been reported in Michigan. For optimal head scab and DON suppression fungicides should be applied from the beginning of flowering up to 7 days post the beginning of flowering. Fungicides applied for head scab management will also provide protection of the flag leaf.

Winter barley is heading in central Michigan. The Fusarium Risk Assessment Map currently shows low risk, however moisture may increase risk potential. Fungicides for management of head scab should be applied once heads have fully emerged, up to 7 days post head emergence, with recent research demonstrating 4 days post head emergence being optimal for head scab and DON suppression. Fungicide products that provide good protection from head scab and stripe rust include Miravis Ace, Prosaro, Prosaro Pro, and Sphaerex. If applying fungicide products for head scab protection, don’t forget to use directional nozzles to increase coverage of the heads. Fungicides applied for head scab suppression will also assist in protecting the foliage.

A discussion on managing wheat and barley diseases and head scab can be found as part of our MSU virtual breakfast series https://www.canr.msu.edu/field_crops/virtual-breakfast/

Wheat and barley disease management discussion for 2023 is posted here: https://www.youtube.com/watch?v=I-TanpnqtEE&t=59s

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

The current focus of the prediction effort is on areas of central IL, IN; southern OH and portions of southeastern PA where wheat is approaching or already at the heading and flowering stages of growth that are critical to the development of Fusarium head blight. The risk map indicates large areas of moderate and high risk of severe disease for much of this region. Growers in these states 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 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 view risk maps for wheat varieties with other levels of genetic resistance to Fusarium head blight. This menu also provides options for viewing additional map features or restricting areas displayed.

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.

You can activate graphs of recent weather and trends in disease risk by clicking on the map. The bottom graph panel displays the disease risk for wheat varieties with different levels of genetic susceptibility to Fusarium head blight.

--Erick DeWolf, Plant Pathologist, Kansas State University

Wheat in Maryland has either already flowered or is finishing-up flowering. The FHB prediction map shows high FHB risk. If your wheat is still in the window for FHB fungicide application (from flowering up to the following 4-7 days) you should consider the application of FHB fungicides: Miravis-Ace, Prosaro, Prosaro-Pro, or Sphaerex. These fungicides are also effective against other foliar fungal diseases such as stripe rust, powdery mildew, and tan-spot etc. Strobilurin-containing fungicides are not recommended for application at this stage.

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

Scab infection risk is high this week across the entire commonwealth as a result of increased precipitation and humidity. Risk levels subside as the week progresses in the central portion of the state, but remain elevated across the south and to the east and west. Most wheat in the south is now flowering, and if your barley or wheat in high risk areas is heading and approaching flowering, consider a fungicide application when the weather allows. Miravis Ace, Prosaro, Prosaro Pro, and Sphaerex all provide very good scab suppression. The Miravis Ace label allows for earlier application than other fungicides, 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. Spray nozzles should be angled at 30 deg down from horizontal, toward the grain heads, using forward- and backward-mounted nozzles or nozzles with a two-directional spray, such as Twinjet nozzles. Additionally, a fungicide treatment at heading using any of these products will also give you excellent control of most leaf diseases as well.

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

Wheat is mostly ending flowering across Maryland now, except for some late-planted fields. The FHB prediction map shows enhanced FHB risk. If your wheat flowered within the past 4-7 days, you are still in the window for FHB fungicide application. This season, we are also observing several foliar diseases such as stripe rust, powdery mildew, BYDV, and tan-spot in our variety trial plots. Some farmers are also reporting these issues from their fields. If you are considering the application of fungicides at this stage, use FHB fungicides: Miravis-Ace, Prosaro, Prosaro-Pro, or Sphaerex. These will control other fungal diseases, in addition to FHB, but not BYDV. For BYDV none of the fungicides can provide control, as it is a viral disease. Genetic resistance is the only real solution for BYDV. Strobilurin-containing fungicides are not recommended for application at this stage.

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