Controlling volunteer winter wheat now is critical
Some summer annual grassy weeds also can act as mite and virus hosts. The greater the density of these grasses, the greater the risk. Controlling them will reduce the risk.
Additional Losses Associated with Volunteer Wheat
Aphids. Volunteer wheat also attracts the Russian wheat aphid and other cereal aphids. If allowed to remain until the new wheat crop emerges, the risk of aphid infestation and barley yellow dwarf increases.
Hessian Flies. Volunteer wheat allowed to survive through late summer and fall also dramatically increases the risk from Hessian fly.
Wheat Stem Sawflies. Some weedy grasses can serve as a host for sawflies. If these weeds are allowed to persist in the environment, their seed production will increase the available hosts for sawflies the following year. This could compound the challenge managing a pest that is already very difficult to manage.
Moisture Loss. Volunteer winter wheat and weeds also use soil water which will otherwise be used by the following crop. The average soil water loss due to volunteer wheat is 3 inches which can result in yield losses of 30 bushels or more in corn or sorghum. Occasionally the loss can be as much as 100 bushels. How does this happen when we only save 3 inches of soil water? With the additional 3 inches of soil water the corn or sorghum crop will survive up to three weeks longer without rain before being lost to drought. Hence, if enough rain is received in time, we have observed yields of 100 bushels or more of corn or sorghum where volunteer wheat and other weeds were controlled after harvest.
Increased Weed Seed. Letting weeds produce seed increases the weed seed bank and makes weed control more difficult in the succeeding crops. The weed residue also makes planting more difficult in the following crop.
Volunteer wheat surviving through the summer and fall creates numerous risks for the subsequent wheat crop as well as other rotated crops. Controlling volunteer will reduce the risks from these threats and ultimately improve the bottom line.