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Look for wheat streak mosaic virus

Carlos Sanchez Pereyra/Getty images Close-up of wheat
SUMMER’S EFFECT: Symptoms of the virus may worsen with stress caused by dry and hot weather.
South Dakota State University Plant Diagnostic Clinic has detected WSMV in recent samples.

Experts at the South Dakota State University Plant Diagnostic Clinic have found wheat streak mosaic virus in recently submitted samples.

WSMV is transmitted by wheat curl mites, and it is also easily transmissible through sap by mechanical inoculation. The mite vector feeds on young wheat growth. Mites develop from eggs to adults within eight to 10 days, and their numbers can increase markedly during relatively short periods when the environment is favorable.

The major symptoms of wheat streak mosaic are:

  • stunted plants with mottled and streaked leaves
  • light- and dark-green, or yellow and green mosaics that coalesce into streaks, which may become necrotic as disease progresses
  • reduced tillering
  • spreading rather than erect growth (prostrating)

Symptoms may worsen with stress caused by dry and hot weather. The extent of yield loss depends on the severity of the symptoms and the proportion of the field that is affected. Sometimes an entire field can be infected, while in other instances, a few scattered plants may be symptomatic.

Wheat streak mosaic can also infect oats, barley, corn, sorghum, millets and other grass species.


If your field is infected with WSMV, foliar fungicides do not offer protection against viral diseases. Fungicides only work to control a fungal disease. This disease is best managed by:

Destruction. Destroy volunteer wheat and grassy weeds before planting winter wheat in the fall. Volunteer wheat and grassy weeds are typically destroyed through a burndown herbicide. A two-week break after the burndown to eliminate the green living bridge is recommended to stop the wheat curl mite’s life cycle.

Later planting. Avoid planting winter wheat before mid-September. Planting early in the fall, especially when temperatures are mild, increases the risk of wheat curl mites still being active and able to land and transmit viruses in emerging winter wheat.

Resistant varieties. Plant wheat varieties that are resistant or tolerant to WSMV.

Crop rotation. Rotating wheat with a broad-leaf crop can help break the disease cycle.

Find more information about managing WSMV and other diseases from SDSU Extension.

Source: South Dakota State University Extension, which is responsible for the information provided and is wholly owned by the source. Informa Business Media and its subsidiaries aren't responsible for any of the content contained in this information asset.


TAGS: Crop Disease
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