The best way to control weeds in wheat fields is not to let them get started in the first place.
“Prevention is the cheapest option for weed control,” said Todd Baughman, Texas AgriLife Extension agronomist at Vernon.
Baughman, speaking at the recent Big Country Wheat Conference in Abilene, said wheat farmers can take several precautions to keep fields fairly weed free.
“Use good quality, weed-free seed,” he said. “Rogue out fields with new weed infestations. Get those plants out of the field.”
He said farmers should manage turnrows, fences, field corners and ditches to remove weeds and prevent them from encroaching into cropland.
“Always combine the worst wheat fields last,” he said. That means weeds that have competed with thin stands don’t move into other fields and cause problems in later years.
“Don’t plant something that you can’t control later,” Baughman cautioned. “For example, some farmers plant rye for pastures and when they convert pasture to cropland the rye becomes a weed and we have limited control options for rye.”
He said crop rotation is an excellent weed prevention technique. “Cotton helps,” he said.
So does proper weed identification. “Know what weed you have. That helps identify the chemical needed for proper control.”
Identification also helps with rate and application timing. “Always follow label directions.”
He said applying herbicides in the fall is often a better strategy than waiting until spring. “With some weeds, we get better control in the spring but fall application improves yield. For the best bang for the buck, apply herbicides in the fall.”
He said it’s important to treat marestail when it’s small. “Otherwise if we spray it and don’t kill it, we just make it mad.”
He noted several particularly bothersome weeds.
Wild oat is particularly troublesome for wheat growers, Baughman said. Wild oat seedling leaves roll counter clockwise and are hairy on the leaf margins with no hairs usually on the top of the leaf blade. “Expect multiple flushes in the fall and spring.”
He said Rescue grass or wild rye has a large, flat seedhead, hairy leaf blades and sheathes. The mature plant may be hairy on the upper side of the leaf. “It is hard to control,” Baughman said.
Japanese brome has a hairy leaf blade and sheath and the mature plant leaves may be hairy on both sides.
Jointed goatgrass has a seedhead that breaks into sections. Mature plant leaves are hairy on the upper sides. “It is difficult to impossible to control,” Baughman said.
He said ryegrass is becoming a problem, particularly on the east edge of the Texas Rolling Plains. “It’s not very competitive but it is difficult to control.”
Cheatgrass may be a misnomer for Texas. “We don’t have true cheat in Texas,” Baughman said.
He said weed competition can take a big toll on yield potential with losses as high as 50 percent with heavy infestations of some weeds. He said weed species, population density, and rainfall affect yield losses. “Early rainfall makes weeds more competitive,” he said.