FHB Alert Blog

FHB Update from IL, 05/15/14

In my travels in the southeastern part of Illinois earlier this week, wheat fields from Pope to Clay Counties were headed out and many were also flowering. The risk of Fusarium head blight (FHB) has recently changed to a moderate risk for much of southern Illinois. Based on the rainy and cloudy conditions that have occurred in these areas, spraying an effective fungicide for FHB management is encouraged. Research at the University of Illinois and other universities has shown that Caramba and Prosaro fungicides are the most efficacious fungicides available in reducing FHB and the associated mycotoxin, deoxynivalenol (DON; a.k.a "vomitoxin"), that can contaminate grain. The best fungicide application timing for FHB management is when flowering is beginning to occur (Feekes growth stage 10.5.1), when anthers are beginning to extrude from the middle part of the wheat heads.

--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

FHB Update from DE, 05/15/14

Delaware and parts of Maryland are now in a moderate to high risk level for scab. I expect this risk to continue through the weekend with heavy rains expected tonight and Friday. Fields entering flowering are at the highest risk for scab. The best fungicides for scab are Prosaro, Caramba, and Proline. Do not apply products containing a strobilurin (e.g. Aproach Prima, Quilt, Stratego, Headline, Quadris, etc.) as strobilurins have been associated with elevated DON levels when applied to the head and scab occurs. There is a 5-6 day window after the majority of a field is flowering and conducive weather occurs to make a fungicide application and maximize efficacy. Ground rigs should have nozzles angled at least 15 degrees in the forward direction and apply at least 10 gallons per acre, with 15-20 being optimal. Aerial applicators should apply at 5 gallons per acre. Shoot for 300 to 350 micron droplet size. Prosaro, Caramba, and Proline will control foliar diseases.

--Nathan Kleczewski, Extension Specialist, University of Delaware

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

FHB Update from AL, 05/15/14

Wheat in North Alabama is just about done flowering. Moderate to high scab risk in Northwest and Northeast corners of Alabama. Yield potential across the Tennessee Valley is high. Very high head counts. Most of wheat in this area was treated with a fungicide for scab within the past two weeks. A few scattered scabby heads were seen in wheat variety trials on Sand Mountain and Tennessee Valley research stations. Some tan spot and glume blotch also seen.

--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 KY, 05/14/14

A lot of wheat has headed out and has been flowering during spotted to heavy rain over a multi-day period. The current models are showing low FHB risk across the state of KY, but I think the models may be underestimating risk at this time. I have seen them switch from green (low risk) to red (high risk) over a very short time. I suspect this is what will happen in the next few days. The bottom line: I think that FHB will be a player in fields that have been flowering during the past 4-5 days, assuming rain has occurred. Time will tell, but I have seen similar conditions in past years lead to at least moderate occurrence of FHB/DON in fields.

It is my understanding that spraying has been hampered by the wet conditions. All I can say is that data from multiple states over the last few years has shown generally good results in FHB/DON control if applications of Prosaro or Caramba are made even 5 days after the onset of flowering. So some fields that were scheduled to be sprayed, might still benefit. Note, the fungicide label will dictate how late in the seasons applications can be made (see days to harvest restriction section on product labels). Even if spraying is possible, I do not encourage applications later than 5 days past the onset of crop flowering. There simply are no data to support later applications.

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

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

FHB Update from DE, 05/14/14

Current forecasts are calling for an 70-80% chance of heavy rain on Thursday-Friday. Fields entering flowering around this time will likely be at risk for scab. You have a 5-6 day window from the start of flowering (Feekes 10.5.1 yellow anthers from the center of heads) where fields are most susceptible and fungicides are most efficacious for suppression of vomitoxin (DON) IF conditions favorable for development of FHB occur. The best fungicides for DON suppression are Prosaro, Caramba, and Proline. Do not use fungicides containing a strobilurin active ingredient (e.g. Quilt, Aproach Prima, Stratego, Headline, Quadris, etc.) as strobilurins have been associated with increased DON levels when applied to heads. Remember that fungicide use gets you on average 42-45% control of DON when applied within that 5 day window of the start of flowering AND the environment is conducive for disease. If recommended fungicides are applied to a moderately resistant variety over 70% control may be achievable. Prosaro, Caramba, and Proline will also control common foliar diseases.

--Nathan Kleczewski, Extension Specialist, University of Delaware

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

FHB Update from DE, 05/14/14

The rain that was forecast earlier in the week did not manifest. However, current forecasts are calling for an 80% chance of heavy rain on Friday. Fields entering flowering around this time will likely be at risk for scab. You have a 5-6 day window from the start of flowering (Feekes 10.5.1 yellow anthers from the center of heads) where fields are most susceptible and fungicides are most efficacious for suppression of vomitoxin (DON). Applications to fully headed fields may have some efficacy, but it is not likely to be optimal. Sparse data exist on heading applications and until we have a more complete picture I do not recommend them. The best fungicides for DON suppression are Prosaro, Caramba, and Proline. Do not use fungicides containing a strobilurin active ingredient (e.g. Quilt, Aproach Prima, Stratego, Headline, Quadris, etc.) as strobilurins have been associated with increased DON levels when applied to heads. Remember that fungicide use gets you around 42-45% suppression of DON when applied within that 5 day window of the start of flowering unless they are applied to a moderately resistant variety, in which case 75% control is achievable.

--Nathan Kleczewski, Extension Specialist, University of Delaware

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

FHB Update from OK, 05/13/14

Oklahoma: At field days yesterday (Cherokee) and the end of last week (Kildare and Lahoma) in north central Oklahoma, wheat was at or approaching the milk stage. Some rain has fallen in local areas where it may help the wheat, but mostly the rain was either too late (southwestern/western OK) or nothing fell. Temperature this week is forecast to be cool (70s), but little chance of widespread rain. No foliar diseases were observed at any of the field days this or last week. We continue to receive samples testing positive for mite transmitted viruses and/or barley yellow dwarf virus, but now that the wheat is turning these samples are becoming infrequent. At the field day yesterday (Cherokee), whiteheads in the trial were observed that were the result of freeze damage, but an occasional plant/tiller also could be found with a dark discoloration of the lower stem. Sometimes this discoloration was indicative of dryland root rot but occasionally a lesion more typical of sharp eyespot also could be found.

--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 TN, 05/13/14

Most wheat south of I-40 has flowered and north of I-40 has or will be flowering over the next week. West and Middle Tennessee are still at low risk for FHB, with some medium risk in East Tennessee. Although there might be an increase in risk with the rain that some areas are receiving, especially if wheat is flowering during that time. Specifically, rain coupled with the warmer temperatures could equate to higher FHB risk for wheat in the northern half of the state where wheat is blooming or about to bloom. Application of a triazole fungicide, like Caramba or Prosaro, can be applied at beginning bloom (FK10.5.1) or shortly after to reduce FHB infection.

--Heather Young-Kelly, Extension Plant Pathologist, University of Tennessee

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

FHB Update from AR, 05/12/14

The risk of scab remains low across all wheat-growing regions of Arkansas. Most wheat in the state is past flowering and likely will not be affected by scab. There is no need for a fungicide specifically for scab, and most wheat is beyond the growth stage when a fungicide can be applied..

--Gene Milus, Plant Pathologist, University of Arkansas

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

FHB Update from KS, 05/12/14

The wheat southern Kansas was more advanced in growth stage than I estimated last week. The hot, dry conditions last week really pressed the wheat growth stages ahead and most wheat in South Central Kansas is already past flowering. Wheat in the central and north central regions of the state are likely at flowering and some fields may already be at the grain filling stages of growth. Parts of central KS received rain over the weekend; however, the risk of severe Fusarium head blight remains low based on dry conditions preceding these rains.

--Erick DeWolf, Extension Plant Pathologist, Kansas State University

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

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