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Tuesday, February 25, 2020

Army Cutworms Warning

Dr. Pat Porter, district entomologist, released this on February 24th.

Hello All,

Katie Lewis asked Suhas and me to tell her what was eating her rye grass plots. We visited today and also checked some wheat. The army cutworms are easy to find in soil around the plants.  I just posted a FOCUS article here:

This is a highly mobile insect, so I have no reason to believe this is a localized problem. Recall that this species is what we call the “Miller Moth”.

Pat Porter

Army cutworms damaging wheat

A researcher at the Lubbock Center asked us to tell her what was eating up her ryegrass plots. Suhas Vyavhare and I checked the plots and some wheat fields near Lubbock and found abundant army cutworm larvae. The growth stages are varied from small to about one-inch, so there is plenty of damage yet to come.

Nebraska has a nice 2017 army cutworm alert that states the treatment threshold is four larvae per square foot (for grain production).  Our publication Managing Insect and Mite Pests of Texas Small Grains (page 8) says, "In outbreak years, fields can have 10 - 20 cutworms per square foot." What we saw today was not to that point, but it is still early and many larvae were small and hard to find. Typical damage includes chewing on leaves, cut plants and severed stems.

The first thing you will see when scouting is the leaf damage. During the day, the cutworms will be beneath the soil surface near the plants.

Army cutworm larva.

Clipped stem on 6-inch wheat plant.

Thanks Dr. Porter!

After checking several wheat fields near Tulia, Kress, and Finney in Hale & Swisher, I can say this pest is attacking wheat in our area at economic levels too.  However, late planted wheat, such as those planted behind ’19 cotton, was showing no damage in the fields I checked.  This makes pretty good sense as the eggs for this species of cutworms should have been laid last fall.  These late fields were already planted a touch late, had issues establishing, and were likely not very attractive to the moths when they were abundant last fall.  This is not a guarantee, but hopefully this is one issue the late fields will not have to face to make a good crop this season.

Blayne Reed

EA-IPM Hale & Swisher
225 Broadway, Suite 6
Plainview, TX 79072
Office - 806-291-5267