Jan. 12, 2012 - With the hopeful Texas wheat crop in the ground, researchers with Texas A&M University-Commerce and the Texas AgriLife Extension Service recently concluded a set of wheat trials to examine the highest-yielding wheat varieties for Northeast Texas.
In the trials, the top 10 soft red winter wheats for Northeast Texas were USG 3295 yielding 77.6 bushels per acre, USG 3555, Syngenta Oakes, Terral LA 841, Pioneer 25847, Syngenta Magnolia, USG 3665, Syngenta Coker 9553 and Terral 8558. The top 10 rounded out with TAMsoft 700, yielding 71.5 bushels per acre.
While potential yield information is helpful, research also included examinations of disease control options.
According to the United States Department of Agriculture (USDA) Research Center, losses due to stripe rust or yellow rust, are commonly around 40 percent, with some fields being completely destroyed.
Stripe rust can be a major problem for fall-seeded wheat in regions with cool nights, or of spring wheat planted adjacent to infected fall-seeded wheat.
The USDA Research center also discloses that leaf rust, also referred to as brown rust, can have Losses over large areas that are generally light to moderate, anywhere from 1 to 20 percent.
Early infection can result in weak plants and poor root and tiller development.
"In our fungicide tests, we did collect data for both stripe rust and leaf rust," said Dr. Curtis Jones, assistant professor and blackland agronomist at Texas A&M University-Commerce.
Wheat growing stages are most commonly referred to in "Feekes," ranging from Feekes 1 (seedling emergence) to Feekes 11.4 (harvest ready).
"Stripe rust, we usually see stripe rust come in at about Feekes 6,7," Jones explained, referring to the stages where the first and second nodes are visible on the wheat plant. "It is a yellow or orange rust. It runs in a stripe along the leaves. There were about four different varieties that we tested our fungicides on. In order to test our fungicides on stripe rust, we used Agripro Patton and Pioneer 25R78, which are susceptible to stripe rust and resistant to leaf rust. Then to test our fungicides for leaf rust we used Pioneer 25R49 and Pioneer 25R54, which are susceptible to leaf rust and resistant to stripe rust."
In the fungicide tests, they used variations of Quilt, Prosaro and Tilt to defend the soft red winter wheat against stripe rust.
"To treat stripe rust ,you must actively scout your wheat fields. Scout fields beginning at Feekes 7," Jones said. "Early infections require longer leaf protection. With early infection, Feekes 7 to Feekes 8, split applications are superior to the use of single applications. If a split application is used, it can provide up to 40 days of leaf protection from stripe rust. A single application only provides adequate protection when infection appears later, in Feekes 9 to 10."
According to the USDA Research Center, stripe rust can be identified by the small yellowish uredinia appearing in linear rows on the leaf. A single infection can result in a stripe the length of the leaf.
The flag leaf, which leaf rust can affect, is not visible until Feekes 8, followed by the ligule of the flag leaf being visible in Feekes 9 and the "boot stage" in Feekes 10.
A leaf rust infection can become apparent when a producer sees the brown circular uredinia common with leaf rust that normally appear on the upper leaf surface, but with severe epidemics sheath infections can occur.
In summary of the wheat trials findings on leaf rust, Jones said they found that there was no significant differences between using single or multiple fungicide applications, as there were in the stripe rust treatments.
"Fungicide rate was not a significant variable in these experiments," Jones said. "Leaf rust occurs about three to four weeks later than stripe rust in North Texas."
Jones said that optimum timing for application against leaf rust would be from Feekes 10 to Feekes 10.5.1 and concluded again that Tebucaonazole was the most cost-effective treatment for producers to use in the instance of both leaf and stripe rust.
To find out more about the tests conducted by Jones and his associates visit www.varietytest.tamu.edu.
