FHB Alert Blog

FHB Update from MN, 07/19/19

Since the Fourth of July holiday temperatures and dew points have been unpleasantly high for small grains. Needless to say, the risk models for FHB have been high for all of Minnesota as the Northern Red River Valley has also received some much-needed rain since my last report two weeks ago.

I have been busy with field days and plot tours across the northern half of the state and scoring diseases in the rye and winter wheat trials in the southern locations. It wasn't difficult to find FHB in the southern trials and even in some of the northern trials the first few FHB infections could be found.

The first symptoms of FHB take about 7 to 10 days to develop. This week, therefore, is a good time to start accessing how much damage FHB may inflict this year as a lot the spring wheat across the state headed between the 4th and 10th of July.

These early FHB infections have the most impact on grain yield. First, the affected florets and spikelet will produce the tell-tale, chalky-white tombstone kernels. Secondly, these early infections have the best chance to grow into the rachis is cut off the nutrient flow to the developing kernels in the florets and spikelets above the initially infected floret, thereby halting grain fill.

One key difference between varieties that are rated very susceptible to FHB and those that are rated moderately resistant, is their ability to slow the disease development into to rachis and cutting off the development of the grain above the initial infection.

And although FHB is really a monocyclic disease, i.e. the current infections will not produce spore that will infect the current crop, the crop remains susceptible until you have the crop in the bin. The spores will come from the same sources of inoculum that provided the ascospores for these first infections. The yield losses of these later infections, however, are much less dramatic and the concern is more the presence of DON in the grain.

Finally, these high temperatures and dew points are already taking their toll on the yield potential of this crop. Especially the high nighttime temperatures shorten the grain fill period, resulting in fewer kernels and lower kernel weight.

--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 SD, 07/17/19

Spring wheat is mostly done flowering but for some of the fields that were planted late and are yet to reach flowering, these are still at risk for Fusarium head blight (FHB/Scab) to develop. The FHB prediction tool is showing moderate to high risk for FHB to develop for the northern half and the southeastern parts of the state. These fields should be protected from FHB by applying a fungicide when 50% of the plants are at flowering. The risk for FHB decreases with time after flowering. Some of the fungicides effective against scab include Caramba, Miravis Ace, Proline, and Prosaro.

--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 ND, 07/13/19

Rain and prolonged periods of high humidity have sustained moderate to high scab risk for susceptible and moderately susceptible varieties. There are a few pockets of moderate to high risk for moderately resistant varieties as well. For wheat that is flowering (or will be flowering soon) in moderate to high risk areas, protect fields with an effective fungicide. As a reminder, research suggests the most amount of FHB and DON suppression occurs when a fungicide is applied at early-flowering or within seven days of early-flowering initiation (seven day application window).

--Andrew Friskop, Cereal Extension Pathologist, NDSU Department of Plant Pathology

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, 07/09/19

The focus of the forecasting effort is now on spring wheat in North Dakota and Northern Minnesota. The risk map is currently showing areas of moderate and high risk in these areas of the country. 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. Much of the winter wheat in the southern US has already been harvested. These areas are now excluded from the analysis and displayed as gray areas on the risk maps.

--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 MN, 07/08/19

Small Grains Disease Update 07/03/2019

The risk assessment models for FHB continues to show a near continuous high risk for FHB in all of Minnesota but the northern half of Polk County and the counties of Marshall and Kittson and the eastern beach ridge of the Red River Valley between Thief River Falls and Fergus Falls. Like last week's update - much of the difference in risk can be explained by overall drier conditions in those areas.

Aphids, meanwhile, have reached the Canadian border. Scout later seeded spring wheat for aphids and treat fields if the threshold of 80% of the stems having one or more aphids is exceeded prior to heading.

Because of the aforementioned drier conditions in Polk, Marshall, and Kittson counties, grasshopper counts are also on the rise. The threshold to treat field margins is 30 nymphs or 20 adults per square yard. Check not just the field perimeter if the wheat was no-till seeded into standing soybean stubble. A threshold of 8 to 14 adults per square yard is used inside the field to start control.

I also found some armyworm larvae in my yard that were quite happy and growing. Check headlands and lodged areas in the field for feeding damage first and treat when 5 or more larvae are present per square foot. If the migrations were smaller and localized, you, again, may only need to treat field margins rather than whole fields.

Finally, this hot, humid weather is pushing the development of the wheat. Having some cooler night not only would lower the risk of FHB but also greatly help preserve the yield potential of this year's crop.

--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 ND, 07/08/19

There is a high risk for scab for susceptible spring wheat varieties in several areas across North Dakota. In addition to elevated scab risk levels in northwest and southeast ND, new pockets of elevated scab risk formed in east central and southwest ND. Over the past couple days, several acres of wheat received a fungicide and it is likely more acres will be sprayed with a fungicide this week. If a moderately resistant variety was sown, scab risk f is moderate to high for a pocket in southeast and southwest North Dakota. Rain and high humidity this week (in the forecast) will likely maintain a moderate to high risk for the most problematic areas.

--Andrew Friskop, Cereal Extension Pathologist, NDSU Department of Plant Pathology

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, 07/03/19

Small Grains Disease Update 07/03/2019

The risk assessment models for FHB is, as was expected, trending higher in the first part of this week, with many parts of the state showing a near continuous high risk for FHB. The only exception being the northern half of Polk County and the counties of Marshall and Kittson. I'm sure the lack of any measurable precipitation since the middle of May is the cause of this lower risk for that part of the State

The hot, humid weather is pushing the development of the wheat. I suspect that many of you will be spending the coming days, including tomorrow's holiday, either scouting fields to determine when to spray or in a tractor making an application at Feekes 10.51.

Consult NDSU's Extension bulletin 'Ground Application of Fungicides for Suppression of Fusarium Head Blight in Small Grains' (https://www.ag.ndsu.edu/publications/crops/ground-application-of-fungici...) to set up your sprayer correctly and get the most benefit of your fungicide application.

Prosaro, Caramba, or Miravis Ace applied at Feekes 10.51 (beginning of anthesis) will provide the best suppression of FHB. Tebuconazole will provide slightly less suppression of FHB. All products mentioned will give very good to excellent control of leaf diseases for the remainder of the season.

--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 SD, 07/01/19

Most of the winter wheat crop is past the window for fungicide application for FHB (scab) management. However, spring wheat in SD varies from jointing to flowering across the state; therefore, spring wheat may have a long window of exposure to conducive weather conditions for scab to develop. Currently, several areas in the eastern half of state and scattered areas West River are showing moderate to high risk for the scab to develop. Spring wheat in the moderate to high risk (yellow and red) areas that is at flowering or will be flowering in the next few days would benefit from a fungicide application to protect against scab and DON development. Also, several winter wheat fields scouted were found with leaf rust, therefore leaf rust inoculum is abundant for spring wheat which still has several weeks of development. A fungicide applied against scab will also protect against leaf rust and other fungal leaf diseases.

--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 MN, 06/28/19

Small Grains Disease Update 06/28/2019

I visited the different yield trials near Rochester, LeCenter, Kimball, and Benson this week past week and talk with producers about their small grains so far this season at the different field days held at those trials.

Both the crops in the trials and in fields I visited look very good. The earliest barley, oat, and spring wheat fields have started to head across not just the south but even northwest Minnesota. These fields will quickly approach anthesis if they did not already with the rapid increase in daytime highs over the past few days.

Overall very little if any disease or insect problems could be found in the trials. The only exception being leaf rust in the lower canopy on susceptible rye varieties in the rye variety trials, a few stripe rust pustules on Prosper HRSW, and the start of net blotch on Pinnacle barley.

The scouts continue to find tan spot and aphids south of the US Hwy 2. Aphids counts are increasing and approaching threshold in a few instances.

The risk assessment models for all three leaf diseases had been trending higher this past week across most of the State. The expected daytime highs over the weekend and early next week will likely mean that the infection risk for tan spot will trend much lower while the risk for leaf rust, and Septoria infections will decline as well.

In contrast, the infection risk for FHB will likely continue to increase. Most of the state has, depending on the level of genetic resistance of the variety, had seen moderate to high risk for FHB in the past couple of days. Keep an eye on the risk models and seriously consider a fungicide treatment at Feekes 10.51 or beginning of anthesis.

--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 ND, 06/28/19

Several spring barley fields are starting to head and spring wheat growth stages range from tillering to boot stages. Some of the earliest planted spring wheat may be heading and potentially flowering next week. The greatest amount of scab risk is on the eastern half of the state with another scab risk pocket in northwest ND. Rain is projected several times in the next week, and this combined with high dew point temperatures, will likely increase scab risk for some. Scout spring wheat fields to determine growth stage and start planning a fungicide application at early flowering in areas with the the greatest amount of scab risk. For barley, an application should be timed at complete full-spike emergence. With both spring wheat and barley, scab and DON suppression can still be achieved if a fungicide is applied 3-7 days after early flowering in wheat or full-head in barley.

--Andrew Friskop, Cereal Extension Pathologist, NDSU Department of Plant Pathology

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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