South Dakota winter wheat planting is fast approaching, and with that comes an opportunity to employ a few preventative management solutions. Although we cannot predict aphid pressure in winter wheat for 2015, there are some steps that may be taken in an attempt to reduce the risk associated with these insects. There are four species of aphids that will infest winter wheat in South Dakota: the bird
This aphid is generally dark green to olive in
English Grain Aphid
Although found in South Dakota, this aphid is rarely of economic concern for small grain farmers. It is typically light green to brown in color. The distinguishing characteristics for the English grain aphid are its black antennae, cornicles, and leg joints. This aphid causes direct feeding injury to the heads of small grains, and will aggregate and feeding on the kernels once heading initiates. The English grain aphid overwinters in southern
This aphid is light green in color with a dark green stripe on its back. The antennae are generally black. Greenbugs feed on the underside of lower leaves of wheat. Feeding by the
Russian Wheat Aphid
This aphid is a dusty blue-green color. The distinguishing characteristics for the Russian wheat aphid are its short
Cultural Preventative Practices
Field sanitation can be important to reduce aphid infestations in winter wheat. Volunteer cereals should be removed to prevent the buildup of aphid populations in the field prior to planting. However, even if in-field populations are reduced, aphids are capable of flying from neighboring fields so infestation is still possible. Resistant wheat varieties exist for Russian wheat aphid, but not for the other three aphid species present in South Dakota. An additional method to prevent or reduce the likelihood of aphid infestation is to delay planting. Optimal winter wheat planting in South Dakota is from September 10 to October 10. Delaying winter wheat planting to the 20 September or later reduces the chances for aphid infestation, which in turn reduces the incidence of BYDV.
Insecticide Seed Treatment
Another preventative management tactic is to use systemic insecticides as seed treatments. Although these insecticides will not be effective for the entire fall season, they do have the potential to reduce early aphid infestations. Because the insecticides are present in plant tissue, they are reported to reduce the incidence of BYDV by managing aphid populations before the virus is vectored to the wheat.
Source: Adam J. Varenhorst and Anitha Chirumamilla, South Dakota State University
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