Armyworms in Texas
Is your lawn discolored? Does it seem to be going Dormant too early?
Armyworm outbreaks are difficult to predict but infestations seem to occur in portions of the state every year especially after rains. Cooler temperatures and widespread rain events across Texas have homeowners scrambling to fight armyworms, according to a Texas A&M AgriLife Extension Service expert.
They will consume freshly cut grass and should be treated when armyworm numbers are beyond three or more caterpillars per square foot.
It is critical to have pesticides ready for applications as soon as armyworm numbers near the recommended threshold. Armyworms in those numbers should be treated immediately because they consume 85% of their diet in the last two or three days of their larval stage.
“The big question is how long will they be a problem, and the answer is until the first killing frost.” “Armyworms are not a ‘spray once and they won’t be a problem’ kind of thing. This could be a two-, three- or four-spray situation if forage for hay or grazing is valuable to them.”
The pest got its name because they appear to march across hay fields, consuming the grass in their path.
Armyworm caterpillars are the larval form of a moth that migrates by the millions northward in the spring and summer to lay their eggs.
Armyworm moths can lay up to 2,000 eggs that hatch in two to three days, according to a 2019 report by Allen Knutson, retired AgriLife Extension entomologist.
Corriher-Olson said there are four to five generations that move throughout the state per growing season. They typically move north from Mexico and South Texas as temperatures warm in the spring. Generations will push further north into Midwestern states, but moths and larvae remain present throughout the state.
They are a common pest of Bermuda grass, sorghum, corn, wheat, rye grass and many other crops throughout Texas.
Armyworms are primarily night feeders unless conditions, such as cooler temperatures with overcast skies, allow, but they try to avoid warmer daytime temperatures.
Armyworms are extremely destructive. Two armyworms per square foot can consume 84 pounds of foliage per acre based on U.S. Department of Agriculture data.
“It’s important to act immediately because if armyworms are left unchecked, they can devastate a lawn in a matter of hours.
Be Ready, Be Proactive
Pesticides are the only way to prevent armyworms from consuming existing stands or new growth.
Insecticides labeled for armyworm control in pastures and hayfields, including pyrethroids, which are affective in killing the caterpillars. But a combination of pyrethroid and growth inhibitor is recommended.
Applicators should always follow all label instructions on pesticide use and restrictions.
Call 214-325-1609
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