Question: How can I control fall Armyworms in lawns?

Answer: The fall armyworm is a caterpillar that can cause a great deal of damage to lawns during late summer and fall. Fall armyworms cause damage by feeding on all of the green above ground plant parts, which can retard plant growth or even cause death to your lawn. Usually, parasitic enemies help manage the fall armyworm larvae, however during cold wet springs this natural control method is not as effective. The major host for this pest insect is grasses. They have the potential to damage golf courses, home lawns, and pastures.

Armyworms measure approximately 35 to 50 mm long and can be green, brown, or black depending on maturity. Fall armyworms feed anytime throughout the day, typically they are most active during the morning or late in the evening. They feed for approximately two to three weeks and then they dig into the ground to pupate.

They can be difficult to control by chemicals, however treatment is more effective if you mow your lawn before applying the control application. Pyrethroids, carbaryl, and acephate can provide control when caterpillars are small. Timing is essential when attempting to control fall armyworms. A soapy water mixture poured on questionable areas of a lawn can be helpful in determining if you have an infestation.

Reminder: The Sampson County Master Gardener Phone Hotline and Plant Clinic takes calls every Tuesday and Thursday from 10 am to 3 pm. The Hotline will observe these operational hours through the end of August. Please call the Sampson County Cooperative Extension Center at (910) 592-7161 with your horticultural questions. Be sure to check out the Ask An Expert Widget at sampson.ces.ncsu.edu for any questions you may have.

For more information, please contact Della King, Sampson County Horticulture Extension Agent at 910-592-7161.