FHB Alert Blog

FHB Update from NY, 06/04/14

Much of the winter wheat and barley in New York State has initiated flowering in the last few days and the remainder of fields are likely to flower over the next week. So the next week remains critical for farmers making fungicide spray decisions for suppression of Fusarium head blight (FHB) and protection of flag leaves from foliar diseases. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and deoxynivalenol (DON) toxin contamination when applied at wheat flowering (emergence of anthers on heads) or at full head emergence in barley (anthers begin to appear on barley before heads emerge from the boot). A flowering application of triazole fungicide should be based on Fusarium head blight (FHB) risk as well as the risks of powdery mildew, rust, and fungal leaf blotches in the upper canopy based on scouting of individual fields. There is an application window of approximately 5-6 days from the beginning of flowering in which reasonable FHB suppression can be expected. Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain. So far the risk of FHB epidemics forecast by the model has remained
low through the early flowering period. And the forecast for precipitation remains low for the next few days. But I urge growers to check the Fusarium Risk Assessment Tool (http://www.wheatscab.psu.edu/) and your local weather forecast frequently as your crop approaches flowering. We will consider the risk of FHB infection of spring wheat and barley in New York in a few more weeks.

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

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

FHB Update from OH, 06/02/14

A June 2 Update: Wheat across Ohio is now between anthesis and early grain-fill. Barring a few late-planted fields in some parts of Northern Ohio that are now at the flowering growth stage, most of our wheat reached anthesis late last week and during the weekend. During that time, the risk for scab remained low, and will likely continue to be low this week, as indicated by the scab risk tool. This is probably because we have had at least 4 rain-free days over the last week. Interestingly, however, relative humidity was very high on several of those days and continues to be high in some areas of the state. In spite of the low risk prediction, Prosaro was still applied to some fields over the weekend. As the wheat enters early grain-fill, the risk for scab decreases considerably, even though late infections may still occur, especially if conditions remain humid, and such late infection may still lead vomitoxin contamination of the grain. However,
at this point, the model seems to suggest that 2014 will likely be a low scab and vomitoxin year in Ohio.

--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

FHB Update from MI, 06/02/14

Wheat heads and flowers will be emerging over the next 2 to 3 weeks in Michigan depending on location. Be sure to have someone in your operation check this site regularly. It is not only helpful in deciding whether or not to spray, but the extent of the risk may also influence the rate of the product you elect to use. In addition, double check your variety's level of susceptibility to the disease as this should also enter into your decision. Our standard fungicide recommendation for the suppression of Fusarium head scab remains Caramba (13.5 oz/ac) or Prosaro (6.5 oz/ac) when half of the dominant heads have at least one flower (anther). These rates can be increased where severe disease pressure is anticipated. How the products are applied matters. Use a nozzle configuration that provides both a forward and backward spray delivering a droplet size classified between the medium and fine rating under moderate pressure. Keep in mind that, as a practical matter, the decision to apply a fungicide needs to also consider leaf diseases that nearly always infect the flag leaves of varieties grown in MI and under MI conditions. Again, check your variety's susceptibility to our most common leaf diseases (see fact sheets at (http://fieldcrop.msu.edu/wheat/ ) )

--Martin Nagelkirk, Extension Educator, Michigan State University

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

FHB Update from WI, 06/02/14

Winter wheat in the southern portion of Wisconsin is at, or past, the flag leaf stage of growth. Disease reports have been few and far between this year. This is because wheat looks very healthy. No diseases where observed on the wheat I inspected this weekend. Septoria leaf blotch I had observed very early this season has subsided and cannot be found now. No powdery mildew was observed in these fields. However, there have been several reports of very minor powdery mildew on wheat near the Janesville area. Weather conditions have been very conducive for powdery mildew, so continue to scout for this disease. If powdery mildew is observed at high levels of severity on flag leaves, then a fungicide application might be warranted.

No wheat rusts have been observed in the fields I have scouted this season. I have received no reports of rusts on wheat in Wisconsin either.

In the next week or two, much of the wheat in Southern Wisconsin will be heading and flowering. This is a critical time to control Fusarium head blight (scab). If conditions are wet and warm during the flowering (anthesis) period, the risk for scab will be higher. To assist in making decisions about scab management, consult the Fusarium Head Blight Prediction Center at http://www.wheatscab.psu.edu. Currently, the risk for scab is low in most of the state. However, as temperatures get warmer and if it continues to rain, the risk can increase quickly.

If a fungicide is warranted for control of scab, products such Prosaro, Caramba, or similar that contain triazole active ingredients can offer suppression of scab and reduce deoxynivalenol (DON) accumulation in harvested grain. These products should be applied within a week or so of the beginning of flowering for reasonable control. Products containing strobilurin fungicides should be avoided on wheat that has headed. Research has demonstrated that levels of DON can be higher after treatment with strobilurin products after heading.

Continue to scout wheat regularly over the next couple of weeks. This will be a critical time to make in-season disease management decisions.

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

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

FHB Update from AL, 06/02/14

Getting ready to harvest wheat as dry down is rapidly progressing statewide with harvesting getting started in southern counties. Seeing low to moderate levels of scab in wheat variety trials at two North Alabama research units. More scab statewide this year than ever before.

--Austin Hagan, Extension Plant Pathologist, Auburn University

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

FHB Update from MI, 06/01/14

Wheat heads and flowers will be emerging over the next 2 to 3 weeks in Michigan depending on location. Be sure to have someone in your operation check this site regularly. It is not only helpful in deciding whether or not to spray, but the extent of the risk may also influence the rate of the product you elect to use. In addition, double check your variety's level of susceptibility to the disease as this should also enter into your decision.

Our standard fungicide recommendation for the suppression of Fusarium head scab remains to use Caramba (13.5 oz/ac) or Prosaro (10.5 oz/ac) when half of the dominant heads have at least one flower (anther). These rates can be increased where severe disease pressure is anticipated. How the products are applied matters. Generally speaking, use a forward and backward oriented nozzle that delivers a moderate/fine droplet under moderate pressure.

Keep in mind that, as a practical matter, the decision to apply a fungicide needs to also consider leaf diseases that nearly always infect the flag leaves of varieties grown in MI and under MI conditions. Again, check your variety's susceptibility to our most common leaf diseases (see fact sheets at (http://fieldcrop.msu.edu/wheat/)).

--Martin Nagelkirk, Extension Educator, Michigan State University

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

FHB Update from OK, 05/31/14

This is likely my last report on diseases for this season. Last week Nathalia Grachet (OSU graduate student) and I traveled to the Oklahoma panhandle for field days and wheat viewing. Although at a low incidence, we did see scattered whiteheads in a few fields indicating root rot. Based on the symptoms, the cause most likely was Fusarium. We also saw symptoms indicative of wheat streak mosaic/high plains disease, but this was in irrigated wheat Jen Olson suggested testing not only for these virus diseases but also for bacteria, which she currently is doing.

Wheat from Stillwater to the panhandle ranged from various stages of dough to approaching full maturity. Many fields obviously will not be harvested, but irrigated wheat in the panhandle looked decent and there were a few (very few) fields of dryland wheat that appeared relatively decent considering the year. I have had one report of a dryland field (nearly a section in size) of ‘Duster’ located just north of the Red River that yielded 33 bu/acre with 61-62 test weight. Apparently this field lies in an area where it picked up some timely showers that helped it considerably.

--Bob Hunger, Extension Plant Pathologist, Oklahoma State University

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

FHB Update from IL, 05/30/14

Wheat in central Illinois is now flowering. The current risk of FHB is low, but this risk will increase if the weather changes to rainy and cloudy with high relative humidity. If the decision to apply a fungicide for FHB management is made, university research has shown that Prosaro and Caramba fungicides are the most effective fungicides available when applied at early anthesis (Feekes growth stage 10.5.1) in reducing FHB disease and DON (vomitoxin) contamination in harvested grain.

Symptoms of FHB are beginning to show up in fields in southern Illinois, but at this time, it is not clear how severe or widespread the disease is.

--Carl Bradley, Associate Professor / Extension Plant Pathologist, 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 http://www.scabusa.org

FHB Update from NY, 05/29/14

Winter wheat and barley in much of New York State are at the flag leaf emerged to boot stages of development and heads will emerge over the next week. The next 14 days will be critical for farmers making fungicide spray decisions for suppression of Fusarium head blight (FHB) and protection of flag leaves from foliar diseases. The triazole products Caramba and Prosaro are the most effective fungicides for suppression of FHB and deoxynivalenol (DON) toxin contamination when applied at wheat flowering (emergence of anthers on heads) or at full head emergence in barley (anthers begin to appear on barley before heads emerge from the boot). A flowering application of triazole fungicide should be based on Fusarium head blight (FHB) risk as well as the risks of powdery mildew, rust, and fungal leaf blotches in the upper canopy based on scouting of individual fields. There is an application window of approximately 5-6 days from the beginning of flowering in which reasonable FHB suppression can be expected. Fungicide products containing strobilurins should not be applied to headed wheat or barley as they may result in increased levels of DON in grain. While the current risk of FHB epidemics is low to moderate over most of the state, that risk could increase with warming temperatures and scattered storms forecast for the first half of next week. Check the Fusarium Risk Assessment Tool and your local weather forecast frequently as your crop approaches flowering.

--Gary Bergstrom, Extension Plant Pathologist, Cornell University

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

FHB Update from KY, 05/29/14

The vast majority of wheat in KY is now passed the most susceptible period for FHB (i.e., flowering, more technically called anthesis). In the far west, symptom expression is almost complete. In many other fields, symptom expression is still developing. Based on what I have seen so far, it looks like most fields have escaped serious damage, but some fields do have moderate incidence of the disease. DON contamination in grain should not be a widespread problem, but it will be an issue in some fields as we approach maturity.

Generally, levels of other diseases are low. Exceptions are that some fields and portions of fields have extensive development of speckled leaf blotch. This is especially true where fungicides were not sprayed. Speckled leaf blotch is a cool season disease and has apparently been favored by the cooler than normal season we are experiencing (overall) thus far. Fortunately, this disease is not very aggressive in terms of yield damage unless it is quite extensive on the flag leaf. Unlike nodorum blotch, which is at currently at very low levels in the state, speckled leaf blotch will NOT move up to the head and cause damage.

Leaf rut can be found in many fields at this time, but incidence and severity are spotty, certainly too little, too late to cause significant yield loss in fields that were not treated with a fungicide. Fields that were treated with a fungicide should be good to go. I have not seen either stripe or stem rust so far this season.

--Don Hershman, Extension Plant Pathologist, University of Kentucky

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

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