Wheat Streak Mosaic Disease Complex in Nebraska-Strategies for Effective Prevention

Friday, June 30, 2023

A severe case of the wheat streak mosaic disease complex (WSMVDC) was recently found in a wheat field in Kimball County, Nebraska. The WSMVDC is caused by three viruses that are transmitted by wheat curl mites (WCMs). The viruses can cause severe damage to wheat crops, resulting in stunted plants, yellow mosaic patterns on leaves, and lateral growth of tillers. The severity of the disease can be increased by co-infections with multiple viruses and by environmental factors such as cool, wet summers and early planting of wheat.

Symptoms:

Wheat streak mosaic disease complex includes three viruses transmitted by wheat curl mites: WSMV, TriMV, and HPWMoV. Symptoms include stunted plant growth and yellow mosaic patterns on leaves. Severe infections can cause lateral tiller growth, exacerbating damage. Co-infections can increase severity, leading to total crop loss. Identifying symptoms is crucial for effective management.

Risk Factors:

Volunteer wheat emerges in wheat fields soon before harvest after a hailstorm, which poses the greatest risk to the WSMVDC. Hail breaks apart grain that is mature enough to germinate. WCMs migrate from the ripening wheat crop to the young volunteer after germination, and both the mites and virus proliferate on it throughout the summer. Volunteer wheat in summer crops like sunflower increases the danger of WSMV.

Other risk factors for the WSMVDC include:

• Crops or grassy weeds that are hosts of WCMs or WSMV

• Cool, wet summers

• Prolonged falls with above-normal temperatures

• Early planting of wheat

There are several management strategies that can be used to reduce the risk of the WSMVDC these includes:

• Controlling volunteer wheat

• Controlling grassy weeds

• Avoiding planting wheat too early

• Avoiding planting wheat next to late maturing summer crops

• Planting wheat varieties with greater resistance or tolerance to WSMV

• Planting high risk fields last

The WSMVDC is a serious disease that can cause significant damage to wheat crops. By understanding the symptoms, risk factors, and management strategies, growers can help to protect their crops from this disease.