Fusarium head blight (FHB), called head scab, has been found in multiple wheat fields throughout Dickinson County.
Fusarium head blight is normally a disease more concentrated in the eastern third of Kansas, but because of weather patterns this spring, we are seeing higher levels of incidence in central Kansas.
“We may see problems with Fusarium head blight this year in many parts of eastern and central Kansas. However, the full extent of the damage is unknown at this time,” said Erick DeWolf, K-State wheat disease specialist.
A little background
FHB is a fungal disease that attacks the wheat head around the time of flowering, generally during wet spring weather. FHB typically overwinters in the soil or on host crop residue. It can also survive on stored wheat seed. Wheat that follows corn can be more susceptible to FHB; however, the Fusariumpathogen is found in most fields at lower levels.
Symptoms of FHB include large tan lesions or bleaching of the parts or all of the wheat head, brown color on the stem just below the head, and pink or orange fungal growth around the kernels.
The tan lesions or bleaching of the heads can often resemble hail damage, but a closer look around the kernels can differentiate hail damage from FHB.
The infection can lead to shriveled, discolored kernels, commonly referred to as “tombstones.”
If infections occur late enough, the kernels may look normal but can still be infected with FHB.
The overall damage to the kernels will be dependent on just how severe the infection is. The greater the severity, the more likely to have high numbers of damaged kernels.
Grain infected with FHB can be a problem to market because the FHB damage can lead to lower test weight and quality. It also reduces milling quality by lowering flour yield and baking quality, discoloring flour and causing odor.
Can be toxic
Another issue with FHB is that it can produce a toxin called deoxynivalenol (DON), more commonly known as vomitoxin. Elevators can test for vomitoxinby using prepackaged kits or by sending grain samples to certified labs.
With most grain contracts, the levels of vomitoxinsare are usually stipulated, and if levels are above that, the loads can be docked or even rejected.
Another toxin, zearalenonecan be found along with vomitoxin but is not as common. Both of these toxins can lead to problems with animal performance including feeding, digestion problems and breeding.
If you planted wheat for the purpose of using it for seed this fall, it would be good to scout that now and see if you can find any FHB.
Seed that has been infected or damaged by FHB could pose a problem for seed wheat this fall.
That seed could have poor germination, poor health, and seedling blights. You can adjust your combines to try to remove as many of the light-weight and diseased kernels as possible.
Also, if you keep seed, make sure it is cleaned several times later this summer to try to remove as many of the infected kernels as possible.
Fungicide seed treatments should also be used to reduce chances of seedling blight and can reduce buildup of FHB fungus in the soil. If a seed is already infected, a seed treatment will have no effect on FHB later in the season, so the disease may still be a problem. Have all of your seed wheat tested for germination rates to make sure you plant enough seed to achieve the desired stand.
There are some cultural practices and environmental factors that would potentially increase the chances of a FHB epidemic in the future.
Some of the cultural practices that would lead to FHB include irrigation, planting wheat after corn, planting wheat after wheat that was infested, no-till or reduced tillage and planting susceptible varieties.
We do not have varieties that are considered resistant, but there are some that are considered moderately resistant, meaning most years, those would be adequate, however, this year even those varieties are showing signs of FHB.
If environmental conditions are favoring FHB, a fungicide can be applied at flowering. However, check with your chemical supplier, crop consultant, or myself to make sure you select the right product for FHB. Most fungicides used this year for rust would not have provided adequate control of FHB.