FHB Alert Blog

FHB Update from MN, 06/14/19

Scouts continue to find tan spot in both winter wheat and spring wheat in their second week of scouting. There were no reports for Septoria spp. or leaf rust. The reported incidence and severity of tan spot increased a bit from the previous week. The risk assessment models mirror their findings as conditions for septoria and leaf rust were not as favorable as they have been for tan spot.

As temperatures and relative humidities are forecasted to increase in immediate weather forecast so are the risk for all three leaf disease complexes are also trending higher.

If you have not completed weed control in spring wheat yet, consider tank-mixing half a labeled rate of a registered fungicide with your weed control program to control early season tan spot in spring wheat when tan spot can found in your fields.

Winter wheat is flowering or Feekes 10.51 in the southern half of Minnesota. To date, the risk model for FHB continues to be trending low, largely because of the cooler temperatures rather than the absence of precipitation. The immediate forecast continues to indicate a low risk of FHB.

However, the application of a fungicide at Feekes 10.51 to suppress FHB is the final opportunity to controls leaf diseases like tan spot, Septoria spp., and leaf rust. Previous research has shown that control of the leaf diseases usually pays in the case of winter wheat. Therefore, I suggest you scout your winter wheat now and consider a fungicide application if any leaf diseases can be found in the lower canopy.

--Jochum Wiersma, Extension Agronomist, University of Minnesota Crookston

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

FHB Update from MI, 06/11/19

Wheat is beginning to flower in the northcentral and thumb regions of Michigan, though some of the October- seeded crop is still a week away. Growers are encouraged to watch this risk map and consider using a fungicide to protect susceptible varieties. Also consider any leaf diseases that might pose a threat to the flag leaf in the weeks to come. Because flooding is preventing ground application in some areas, aerial application may be a reasonable alternative. Although there are few studies on applying fungicides to wheat by air, it is worth looking at the Extension bulletin called "Aerial Application of Fungicide for the Suppression of Fusarium Head Blight". This piece has a few suggestions for obtaining good coverage of the wheat heads including the use of: 1) a minimum of 5 gallons/acre of water; 2) a “large fine” to “fine medium” spray droplet; 3) a minimum pressure of 30 psi and 4) an application altitude of 8 to 12 feet depending or the aircraft.

--Martin Nagelkirk, Extension Educator, Michigan 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 https://www.scabusa.org

FHB Update from MN, 06/11/19

Commentary 06/10/2019

Scouts reported tan spot in both winter wheat and spring wheat in their first week of scouting. The risk assessment models mirror their findings as the cooler than normal temperatures were only favorable for tan spot.

The immediate weather forecast not only will increase the risk for tan spot but also for Septoria spp. and leaf rust infections. I expect leaf rust to make its way into at least southern Minnesota as severe leaf rust was reported on unsprayed and susceptible winter wheat varieties in eastern Nebraska.

Consider tank mixing half a labeled rate of a registered fungicide with your weed control program to control early season tan spot in spring wheat when tan spot can found in your fields.

Winter wheat is approaching flowering or Feekes 10.51 in the southern half of Minnesota. To date the risk model for FHB has been trending low, largely because of the cooler temperatures rather than the absence of precipitation. The immediate forecast continues to indicate low risk of FHB. However, the application of a fungicide at Feekes 10.51 to suppress FHB is the final opportunity to controls leaf diseases like tan spot, Septoria spp., and leaf rust.

Previous research has shown that control of the leaf diseases usually pays in the case of winter wheat. Therefore, I suggest you scout your winter wheat now and consider a fungicide application if any leaf diseases can be found in the lower canopy.

--Jochum Wiersma, Extension Agronomist, University of Minnesota Crookston

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

FHB Update from WI, 06/10/19

Most varieties of winter wheat are now at anthesis (flowering) in southern and south-central Wisconsin. Now is the time to manage Fusarium head blight (FHB or scab) and vomitoxin. The Fusarium head blight Risk Model (http://www.wheatscab.psu.edu) has tapered off in the last week in terms of predicted risk of FHB. However, there are still areas of moderate to high risk in the primary wheat growing region of the state. Weather conditions are projected to turn excessively wet over the next 3-5 days, thus I predict risk will rise again. FHB was severe in many wheat fields in 2018, and considering the weather this season and reports of FHB to our south, I anticipate 2019 being problematic. Fungicide products of choice to control FHB in Wisconsin include Caramba, Prosaro, and Miravis Ace. Multiple years of data in Wisconsin suggest that the best application window for any of these products begins at the start of anthesis until 5-7 days after the start of anthesis. Applying fungicide before anthesis or more than 7-10 days after anthesis will result in poor performance against vomitoxin accumulation. Information pertaining to recent fungicide studies on winter wheat in Wisconsin, can be found at this link: https://badgercropdoc.com/wp-content/uploads/sites/5/2018/12/2018-Fungic... and scrolling to page 12. Other reports can be found here: https://badgercropdoc.com/research-summaries/.

--Damon Smith, Extension Plant Pathologist, University of Wisconsin-Madison

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

FHB Update from SD, 06/10/19

Winter wheat in South Dakota ranges from flag leaf to flowering as of the week of June 10. Wheat that is heading or flowering is most prone to Fusarium head blight (FHB or scab) development provided the weather conditions are conducive, since the source of inoculum is plenty in the environment. Based on the FHB prediction tool, the risk for FHB is currently low in South Dakota with exception of few scattered areas along the Missouri River in Lyman, Brule, Buffalo and Hughes Counties where the risk is mainly moderate. The decision to apply a fungicide to manage FHB should be based on the current risk and also on the weather forecast in the next several days if wheat is at heading or flowering. High humidity or rainfall in the forest can change the risk for FHB from low to high in a short time. If a susceptible or moderately susceptible cultivar was planted, a fungicide is advised for areas in moderate or high risk for FHB. The best fungicide timing for FHB management is at flowering (50% of the plants are flowering). Follow this link for fungicides effective against FHB shorturl.at/hlDU5

--Emmanuel Byamukama, Extension Plant Pathologist , South Dakota 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 https://www.scabusa.org

FHB Update from MI, 06/06/19

The weather pattern has been quite favorable for Head scab during the past couple weeks so growers are encouraged to consider fungicide use if conditions warrant. Heads and flowers will likely emerge in southern counties during the next week. We may still be a week or more away in the Thumb and north-central counties. We now have three main products from which to choose: Caramba, Miravis Ace and Prosaro. If one elects to treat:: apply a few days after the first flowers emerge; target the heads by raising the boom to 8 to 12 inches above the heads; use dual nozzles directed both forward and backward ( or, if using single nozzle, at least direct it forward to achieve as much spray deposition on heads as possible); and create a moderately fine spray (if a misty vapor is rolling off the boom, the particles are too small and adjustments should be made).

--Martin Nagelkirk, Extension Educator, Michigan 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 https://www.scabusa.org

FHB Update from NY, 06/04/19

The Fusarium Risk Assessment Map (http://www.wheatscab.psu.edu/riskTool.html) continues to indicate a moderate to high risk of Fusarium head blight (FHB) for several areas of New York. Much of the state’s winter wheat will initiate flowering this week. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and deoxynivalenol (DON) mycotoxin contamination when applied at flowering (emergence of yellow anthers on heads). A flowering application of triazole fungicide 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.

All but the latest planted winter barley is beyond the timing for a fungicide application. In barley, maximal suppression of FHB and grain contamination by DON results when fully emerged heads are sprayed with full label rates of Caramba or Prosaro fungicides. Application up to 7 days after full head emergence may still result in significant suppression of FHB and DON.

Attend Cornell’s Small Grain Management Field Day (http://events.cornell.edu/event/2019_small_grains_management_field_day ) on June 6 to learn more about integrated management of FHB and DON and to view the leading varieties of winter wheat, barley, and rye.

--Gary Bergstrom, Extension Plant Pathologist, Cornell 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 https://www.scabusa.org

FHB Update from US, 06/03/19

The focus of the forecasting effort shifts north this week to MI, NY and WI. The risk map is showing some moderate to high risk in these areas today. Growers in these areas should consult with local university extension and other advisors to further evaluate the risk of disease and need for fungicide treatment. Selecting the state of interest from the menu to the left of the map will zoom to show more detail and display commentary from local disease specialists.

--Erick DeWolf, Extension Plant Pathologist, Kansas 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 https://www.scabusa.org

FHB Update from OH, 06/03/19

Most of the wheat fields in the northern half of the state reached anthesis last week. The remaining fields will reach this critical growth stage during this week. The risk for Fusarium head blight (FHB) has been moderate-to-high over the last 5-7 days on susceptible varieties planted in the northwest corner of the state. However, persistent rainfall, soggy fields, and difficulties scheduling an aerial application, prevented some fields from being sprayed to control scab and vomitoxin at the anthesis/flowering growth stage. If the risk for scab was high a few days ago when your field reached anthesis, but you were unable to apply a recommended fungicide, you can still make an application up to 6 days after anthesis and see good results in terms of scab and vomitoxin control. This is true for Prosaro, Caramba, and Miravis Ace. Applications made 4-6 days after anthesis are effective against scab and vomitoxin and are particularly useful when the weather following anthesis is consistently favorable for scab. In fact, even if the scab risk had decreased over the last few days, a late application would still be warranted, given that conditions were favorable for scab during the week leading up to anthesis.

--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 https://www.scabusa.org

FHB Update from IL, 06/03/19

Much of the wheat has flowered in the S and Central parts of IL. Expect late flowering wheat in the N most parts of IL to flower within the next 7-10 days. Over that period of time additional rains are forecast, which may slightly elevate risk levels. Wheat that flowered approximately 3 weeks ago should be showing symptoms of disease if infections occurred. For more on harvest-based management strategies for FHB go to http://cropdisease.cropsciences.illinois.edu/?p=908

Remember to switch the model to best approximate the resistance level of your varieties. The map defaults to susceptible, but your risk will change substantially if you planted moderately resistant or even moderately susceptible varieties.

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

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

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