Fusarium head blight (FHB) or head scab has been reported in western Ohio. As we approach wheat harvest, there are strategies to reduce the effect of FHB and DON (or vomitoxin) contamination on grain quality.
Prior to harvest, it is important to scout fields, especially those with varieties with poor resistance to FHB and where no fungicide was applied at flowering. The main symptoms of FHB are bleached spikelets and shriveled kernels. In some cases, pinkish fungal growth may also be observed at the base of the infected spikelets (Figure 1).
If you suspect FHB, thresh 2-3 handfuls of heads from multiple areas of the field and check for shriveled, whitish-pink colored grain. In fields infected with FHB where high DON levels are anticipated, take the following measures to avoid quality losses:
- Increase the combine fan speed to remove lightweight, diseased kernels. The level of damaged kernels is highly correlated with DON levels, so physically removing smaller and lighter kernels will reduce DON contamination. Typically, if more than 5% of your grain sample contains Fusarium-damaged kernels, you will benefit from increasing the fan speed and air flow through the combine.
- Harvest fields with high FHB levels early. If the weather cooperates, harvest at 18 to 20 percent moisture.
Dry-harvest grain to below 15 percent moisture before storage and store at cool temperatures (35 to 45 degrees Fahrenheit) to reduce additional fungal growth and DON contamination.