August 6, 2010

Wheat producers whose crop was damaged or destroyed by hail this year need to take special precautions soon to prevent viruses such as wheat streak mosaic and High Plains virus from damaging their 2011 winter wheat crop.

This spring wheat producers in western Nebraska had the great fortune of ample precipitation, leading to above normal yields. However, for some, this precipitation fell in the form of destructive hail.

It is critical to plan now for volunteer wheat control prior to sowing next year’s wheat crop, especially in these hail-damaged areas. Here is why.

During wheat harvest, some grain always falls to the ground to produce volunteer wheat. This volunteer wheat does not raise concerns about viruses in the following crop, but rather's it's the volunteer wheat produced by hail damage that is a problem. This wheat has had much more time to grow and serve as habitat for wheat curl mites, which can transmit viruses such as wheat streak mosaic virus and high plains virus to the 2011 winter wheat crop.

Prior to harvest, mites will be carried on the wind out of old wheat to green volunteer plants. If these volunteer plants are not controlled, they will serve as a host for infestations and viruses for seedling winter wheat.

Volunteer Control

Timing is crucial. Control volunteer wheat early, before next year’s crop emerges. When herbicides are applied to volunteer wheat after the new crop emerges, mites will just move from the dying volunteer wheat to the young seedlings. Inoculation of seedling wheat by wheat streak mosaic and high plains viruses can cause significant damage to the crop.

To effectively manage wheat streak mosaic virus:

1. Control volunteer wheat after harvest. This is particularly important this year because many fields suffered hail damage
2. Avoid early planting. Do not plant winter wheat too early for your growing area. Allow herbicides to effectively kill off volunteer wheat to prevent the spread of wheat curl mites into the new crop.
3. Avoid planting winter wheat next to late-maturing, green corn, which is also a host for the mite as well as wheat streak mosaic virus.

For more information on wheat production and management, visit the Wheat Production section of CropWatch at  wheat/

Jeff Bradshaw, Extension Entomology Specialist, Panhandle REC
Steven Wegulo, Extension Plant Pathologist
Greg Kruger, Cropping Systems Specialist, West Central REC
Robert Klein, Cropping Systems Specialist, West Central REC