Fusarium Head Blight
Wheat growers have struggled to combat Fusarium head blight (FHB) for years, and recent outbreaks have caused increased concern about prevention. Fusarium head blight, also called head scab or simply scab, is a problem not only because of its impact on yield potential but also because of its ability to produce the mycotoxin deoxynivalenol, or DON. High levels of DON can lead to significant dockage and even rejection at the elevator if levels are above thresholds, because it can adversely affect livestock and human health when ingested. Make sure that you take these steps to prevent FHB from negatively impacting your harvest and your bottom line.
1. Choose Seed That Protects Your Yield Potential
When choosing your wheat seed, select varieties with moderate to high levels of resistance to alleviate concerns about FHB later in the season. Look to university trials, third-party data and previous crop reports to validate a variety’s resistance.
Planting Certified Seed, which is clean and free from diseases, can also ensure that you aren’t replanting infected seed, which can spread and negatively impact your season. Even saved seed that has been cleaned of all shriveled and small seeds can still contain grain that was infected later in the season when kernels were close to full weight.
2. Plant on Tilled Fields
FHB survives through residue left on or above the soil surface, most commonly after a corn crop, but also following wheat or barley crops. Tillage can help incorporate the residue from these crops and prevent spread by infected stubble if FHB has been a problem in your area. Tilling the soil also breaks up the spores through which the disease normally travels, reducing the risk of it transferring to other fields.
3. Use Crop Rotation and Stagger Maturities
In areas where FHB is known to be an issue, stagger wheat planting dates and maturities of your varieties so they flower at different times. This can help reduce the risk of the entire crop becoming infected.
Planting wheat in a field that has not recently held a host crop, such as a prior soybean crop, can also help to break up the disease cycle in areas where FHB is known to thrive.
4. Scout Early and Often
The critical period for FHB infection occurs before flowering, when high humidity and moderate temperatures are present. Initial symptoms appear as bleached, tan to brown spikelets that when peeled back produce “scabby” grain that looks pinkish and shriveled—these are sometimes referred to as ‘tombstones’. In severe cases, spikelets may not produce grain at all. The severity of the infection varies, but if infections occur on the stem immediately below the head, the entire head may become infected.
If conditions in your area are likely to cause infection, it is important that you scout early and often to help you locate the disease before it spreads. Monitor disease reports and weather reports in your area and surrounding areas to time your scouting efforts.
5. Apply Fungicide
Before deciding to use a fungicide, consider your variety’s susceptibility, your crop production practices and local crop report and weather forecasts. Several fungicides are available for use against FHB that vary in effectiveness depending on application timing, spray coverage and disease pressure. If fungicide is necessary, there is a short window where applications will be most effective. The application should occur at early flowering when conditions are favorable for infection.
Though FHB can be a devastating disease, it can be prevented. Keep FHB from spoiling your harvest by taking the necessary steps before and during the season to ensure a healthy wheat crop.
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