04/24/1991

Small Grains Field Day Held at Gulf Coast Substation

FAIRHOPE, Ala.—Alabama Agricultural Experiment Station researchers were able to win the battle with Hessian flies and aphids in winter wheat last year, but whether this will mean better yields remains uncertain.

Speaking at a recent Small Grains Field Day at the Gulf Coast Substation in Fairhope, Auburn researcher Paul Estes, noted that Hessian fly can be a major problem in Alabama wheat because up to six generations may be produced in one growing season, compared to only two in the Midwest. Barley yellow dwarf virus (BYDV) is related to Hessian fly only in that the disease is vectored by another insect--aphids. The idea behind dual control is that systemic insecticides that control Hessian fly also control aphids, thus eliminating the virus vector, according to Estes.

In tests at the Gulf Coast Substation, the soil-applied insecticides Thimet and Disyston were used for Hessian fly/aphid control. Because of the multiple generations of Hessian fly and the long time period between application and emergence of insects, researchers didn't expect control in the spring from the fall-applied insecticides. "We saw a reduction in Hessian flies and aphids in the spring, compared to our check plots," according to Estes, who also is an assistant professor of entomology at Auburn.

The Auburn researcher was careful to point out that the reductions in insect numbers did not equate to increased yields. The reduction in aphid numbers likewise did not reduce the incidence of BYDV. However, it does demonstrate that both pests can be reduced with long-acting systemic insecticides and could lead to new production practices to control these sporadically occurring, but potentially yield limiting problems for Alabama wheat producers.

Auburn researcher Don Thurlow provided an update on small grain variety tests at the Substation. He noted that some northern varieties of wheat, such as Williams, will produce less yield when planted late in the season. Conversely, Florida varieties, planted early in the season, often head out in late February and are destroyed by cold weather. Thurlow, who is an associate professor of agronomy at Auburn, noted that complete results of the statewide small grain variety test are available from the Department of Research Information at Auburn.

During a presentation on small grain diseases, Auburn researcher Dan Collins noted that the decision whether to use fungicides should be based on the economic value and yield potential of the crop. Researcher Bob Gudauskas showed results of several fungicide screening tests on wheat. In these tests last year, wheat treated with Tilt at 1.8 ounces per acre, Bayleton at two ounces per acre, and Folicur at 3.6 ounces per acre all produced between 55 and 64 bushels per acre. Over the past six years, which includes some years with virtually no disease, these fungicides have averaged about 15 bushels per acre increase over nontreated plots.

Several growers in attendance expressed interest in canola, a relatively new crop to the Gulf Coast area. Auburn researcher Paul Mask noted that about 2,500 acres of canola are being grown this year in Baldwin County. Canola is a type of rape, or turnip, that has been grown for many years as a source for industrial grade oils. Recent improvements in rape varieties made canola oil conducive to human use, and it has become the third leading oil for cooking in the world.

Mask, who is an assistant professor of agronomy, said that researchers are looking at 44 varieties of canola at the Gulf Coast Substation. Based on preliminary research, he said it appears canola requires well drained soils to avoid freeze damage and shallow planting depths to insure a good stand. He noted that canola is susceptible to a number of soilborne diseases and that 2 to 4-year rotations likely will be required to grow it in Alabama.

The meeting was held at the 800-acre Gulf Coast Substation. Hosts for the meeting included Substation Superintendent Emmett Carden; Ronnie McDaniel, associate superintendent; and Malcomb Peques, assistant superintendent. The Substation also will be the site of a Strawberry Field Day on May 6.

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By:
Roy Roberson