Updates on Fall Armyworms in Iowa

September 15, 2021

A few weeks ago we posted about fall armyworm masses being found throughout Iowa. Here is a link to an article that Dr. Donald Lewis and myself presented on the Horticulture and Home Pest News last week. This outbreak is growing across the state, with calls from Burlington to Cherokee. 

Our observations are as follows:

Young grass including that seeded last fall seems to be recieving a higher rate of damage than older yards. Turf type tall fescue also is being destoryed in may cases over yards with Kentucky bluegrass. Golf course damage seems to be limited to some roughs but not other parts as of yet.

Scouting is key for these pests, which includes looking for how many and how big they are. Younger fall armyworms will be easier to control than larger ones. I would suggest consulting a commerical turfgrass applicator if you decide to control fall armyworms. They have the proper training to apply pesticides, and should use products that will help with the problem. 

If you do have damage make sure to keep the soil moist during recovery. This will include watering once in the morning and once in late afternoon, but avoid watering to the point of standing water. This prevents the plant from drying out due to the sun and temperatures, and also limits any extra stress on the plants. 

A lawn in Iowa damaged by fall armyworms.Fall armyworms in a yard.

Fall armyworms can cause what looks like drought damage, but upon closer investigation the caterpillars can be spotted in the canopy or on the soil.