FHB Alert Blog

FHB Update from NY, 05/21/18

This is a critical week for management of Fusarium head blight (FHB) in winter malting barley in New York. Some winter barley fields in New York are fully headed now and many more will head out this later week. Even though we have had frequent rains, the Fusarium Risk Assessment Map (http://www.wheatscab.psu.edu/riskTool.html) shows mostly low risk of Fusarium infection in New York because temperatures have been considered too low for spore production in many areas. A moderate to high risk of FHB is indicated for areas of the Southern Tier, southern Hudson Valley, and Long Island. Maximal suppression of FHB and grain contamination by deoxynivalenol (DON) mycotoxin results when fully emerged heads of winter malting barley are sprayed with full label rates of Caramba or Prosaro fungicides. A heads emerged spray with these triazole fungicides also helps protect upper leaves against fungal leaf blotches, powdery mildew, and rust. Foliar sprays of Caramba or Prosaro up to seven days after head emergence may still result in significant FHB and DON suppression. Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain.

Winter wheat is generally a week or more behind in development from winter barley planted on the same fall date. Winter wheat in New York varies from stem elongation to flag leaf visible stages. We should reach the critical fungicide application window for winter wheat over the next two weeks. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and DON contamination when applied at flowering (emergence of 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 suppression can be expected. Check the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu/) and your local weather forecast frequently as your winter wheat crop approaches heading and flowering.

--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 IL, 05/21/18

The majority of wheat in the state started to flower at some point last week, with any remaining wheat likely to flower by the end of this week. The weather thusfar has not been conducive for FHB and model predictions indicate a low potential for outbreaks this season. Regardless, scouting for FHB should occur around 18-24 days after flowering, as this is the time when you are most likely to see the distinctive pink discoloration and bleaching contrasted with healthy, green heads. If a significant portion of the field contains FHB, that field should be scheduled for early harvest, and fan speeds increased to remove tombstones.

--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

FHB Update from PA, 05/21/18

Scab risk continues to be very high across PA this week. If your wheat has begun to flower, spray at your earliest opportunity to protect it from infection. Recent wet weather will cause spores to continue to form all week. Time your application on fields that are at the beginning of flowering, up to about 5 days following the beginning of flowering. Remember, sprays applied PRIOR to flowering will NOT provide significant suppression of scab or toxin production. Caramba or Prosaro are effective on scab and give control of most leaf diseases and glume blotch. They do not need to be tank mixed with another product to control these diseases. If these products are unavailable, Proline and Folicur (which together provide the same chemicals as Prosaro) may be tank mixed at a rate of 3 + 3 fl oz/A. 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. Do NOT use any strobilurin-containing fungicides at heading or beyond.

--Alyssa Collins, Extension Field Crops Pathologist, Penn 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 OK, 05/17/18

Although not as obvious as in previous weeks, powdery mildew is still hanging on in Oklahoma, and has even moved up onto the heads in some fields. One such field is my foliar fungicide trial here at Stillwater. Examining this trial yesterday revealed many of the lower heads were lightly to moderately infected with powdery mildew. This is one of the few times I have seen powdery mildew move onto wheat heads in Oklahoma. It is important to note that these infected heads are the ones produced on the lower tillers beneath the main, taller tillers. I did not find any powdery mildew on any of the higher heads. This appears to me to be a light to moderate infection severity, but I’ve not had a lot of experience with powdery mildew on wheat heads, so this is just my estimation. Exactly how much of an impact this powdery mildew will have on yield and test weight may be hard to determine because the level of powdery mildew on these heads seemed to be fairly constant across all treatments.

Yesterday, I also observed leaf rust on scattered leaves in the foliar fungicide trial at Stillwater (mostly in the not-sprayed control plots). Typically this was just a couple pustules scattered on a leaf. This indicates that leaf rust is starting to appear and may increase a bit over the next 7-10 days. However, this is a late infection as this trial is at late milk to early soft dough. Hence, the leaf rust will have only a minimal impact on yield even if it does increase significantly.

Finally, Brad Babek (County Educator, Washita County in southwestern Oklahoma) reported increasing areas of white heads in wheat fields. In cases where I have observed such heads this year, it has been due to dryland (Fusarium) root rot. Typically the roots will be rotted and often the lowest part of the stem is discolored (dark) and often there is a pinkish-purple color associated with the lower tiller and roots. Splitting such a tiller often reveals a stem filled with white or pinkish-white fungal growth.

--Bob Hunger, Extension Plant Pathologist, Oklahoma 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 MD, 05/15/18

Wheat is anywhere from beginning to heading to past-flowering in Maryland. With the current wet weather, the risk of FHB is increasing in the region. Farmers who currently have their wheat flowering are advised to spray for FHB. Those who will have flowering in the coming week or so are advised to be prepared to spray, keeping a close watch on the risk forecast. If the wheat is already past flowering, you don’t need to spray. The fungicides recommended for FHB are Prosaro, Caramba, or Proline. Do not apply a strobilurin-containing fungicide.

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

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 VA, 05/15/18

FHB risk is increasing in Virginia and will continue to increase over the next several days. Risk is highest on the Eastern Shore, but susceptible varieties such as Shirley that are flowering over the next week will be at moderate to high risk in many portions of the state. Growers should monitor the FHB risk tool as their wheat crop begins to flower and consider applying a fungicide if risk is moderate to high. Wheat that has completed flowering is no longer susceptible to infection. Fungicides should be applied at early flowering or up to one week later. Do not apply a strobilurin-containing fungicide since this can increase DON contamination. Recommended fungicides include Prosaro, Caramba, and Proline.

--Hillary Mehl, Extension Plant Pathologist, Virginia Tech

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, 05/15/18

Although the wheat crop is now flowering in some southern counties, the scab forecasting system (http://www.wheatscab.psu.edu/) indicates that the risk of head scab is low (the map is green), suggesting that conditions have not been favorable for the scab fungus to infect. However, if you still plan to spray for head scab, Prosaro or Caramba should be your fungicides of choice. The new fungicide, Miravis Ace, which seems to be just as effective as Prosaro and Caramba, based on a limited number of trials, is probably not yet available. STAY AWAY from the strobilurins when it comes to head scab management. These fungicides tend to increase rather than reduce vomitoxin contamination.

Continue to monitor the crop and the weather in the north. Barley will begin heading-out later this week and into next week, while wheat is still about a week away from heading in the north and about two to three weeks away from flowering. There is still ample time to apply a fungicide for head scab and vomitoxin control, if conditions become favorable during the next few weeks.

--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 PA, 05/14/18

If you have wheat flowering this week or barley heading this week in DelMarVa or most of Pennsylvania, please consider spraying your crop for scab if you have not done so already. Persistent wet weather and warm temperatures are triggering Medium to High risk levels in many areas of the region. Time your application on fields that are at the beginning of flowering, up to about 5 days following the beginning of flowering. Remember, sprays applied PRIOR to flowering will NOT provide significant suppression of scab or toxin production. Caramba or Prosaro are effective on scab and give control of most leaf diseases and glume blotch. They do not need to be tank mixed with another product to control these diseases. If these products are unavailable, Proline and Folicur (which together provide the same chemicals as Prosaro) may be tank mixed at a rate of 3 + 3 fl oz/A. 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. Do NOT use any strobilurin-containing fungicides at heading or beyond.

--Alyssa Collins, Extension Field Crops Pathologist, Penn 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 MO, 05/14/18

In Missouri, FHB risk predictions have indicated that risk of infection was low throughout this past week as wheat has begun to flower in much of the southern part of the state. However, as the humidity begins to increase and the forecast calls for intermittent rain events, the risk of FHB could increase in some areas. If a fungicide application is considered, the fungicides Prosaro and Caramba applied at Feekes 10.5.1 (50% of the plants in the field are beginning to flower) are considered the best options for FHB management. University research also has shown that the application of a fungicide up to 5 days after Feekes 10.5.1 may provide similar control. Strobilurin-containing fungicides are not labelled for control of Fusarium head blight and, if applied at later growth stages such as Feekes 10.5.1, may result in increased DON levels in the grain.

--Kaitlyn Bissonnette, Extension Plant Pathologist, University of Missouri

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 VA, 05/09/18

The FHB risk for Virginia remains low in most areas. However, risk is moderate to high for wheat currently flowering in coastal areas. For FHB control in wheat, apply Prosaro, Caramba, or Proline at beginning flowering or up to one week later. For barley, fungicides should be applied at head emergence. Do not apply a strobilurin containing fungicide after the flag leaf emergence stage since this can increase DON levels in the grain.

--Hillary Mehl, Extension Plant Pathologist, Virginia Tech

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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