Stripe rust muffles wheat

After an extremely wet winter and early spring in the Southwest, even dryland wheat looked strong in much of Texas as harvest approached.

But the jubilation over the best wheat in 10 or 15 years was tempered by not only the world glut of wheat and poor wheat prices, but also an outbreak of a new race of stripe rust in Texas this year.

Robert Duncan, Texas AgriLife Extension state wheat specialist, College Station, says the stripe rust surfaced in 2010 from eastern Texas to Dallas and on to west-central Texas and Abilene, as well as north-central Texas.

Key Points

• A new race of stripe rust spread rapidly across Texas in recent months.

• Stripe rust is a far more severe disease than leaf rust in wheat.

• Fall treatment is preferable to spring for some of the toughest weeds.

As growers prepare to plant a new crop of winter wheat this fall, the new race of the disease, and how widespread it is, is troublesome.

Duncan notes the new race is so prevalent in wheat that only three varieties have been identified as resistant: Fannin, Doans and TAM 111.

While leaf rust, powdery mildew and barley yellow dwarf virus are among other wheat diseases for which growers should be on guard, they don’t hold a candle to stripe rust. Rob Borchardt of AgriPro Wheat, Vernon, Texas, puts it in sharp perspective: “Leaf rust can cost you a lot of bushels,” he notes. “Stripe rust can wipe you out.”

Duncan agrees in the severity of stripe rust. He also emphasizes it’s important to recognize that.

“Stripe rust and leaf rust are completely different pathogens,” Duncan says. “So don’t think because a disease has ‘rust’ in its name that it is the same disease. It’s a totally different organism. So it’s real important in variety consideration.”

Get on weeds this fall

Todd Baughman, Texas AgriLife Extension agronomist, Vernon, says wheat producers need to pounce on weeds in the fall, not the spring, to get the most bang for their buck. He notes many good products are available for pests like mustard weeds and thistles, but grasses and wild oats are more challenging.

Commonly, growers in west-central and northern Texas experience true cheatgrass, rescuegrass and Japanese brome among their worst grasses in wheat fields. “Rescuegrass is twice as tough to control as true cheatgrass,” Baughman allows. “And the brome falls somewhere in the middle.”

Treatment must be timely for best results. “The key is treating in the fall,” Baughman says. He notes waiting until spring to attack these weeds, especially if after a wet winter, can reduce effectiveness by about 10% to 50%. “It’s especially important to treat rescuegrass in the fall,” Baughman notes.

He says three — Maverick, Finesse Grass & Broadleaf, and PowerFlex — do a great job in controlling rescuegrass. Baughman says producers can expect good results this fall if they treat four to five weeks after planting wheat to get the first flush of weeds.

David Drake, AgriLife Extension agronomist, San Angelo, notes Texas A&M work shows 1.2 pounds of nitrogen is required for every bushel of wheat produced. He says some residual N may already be in the soil, so it’s extremely wise to soil-test before applying expensive fertilizer.

This article published in the July, 2010 edition of THE FARMER-STOCKMAN.

All rights reserved. Copyright Farm Progress Cos. 2010.