|Fall army worm PHOTO/Kris Braman, UGA Entomologist|
The recent article "Fall Armyworms in Turf," by UGA's Will Hudson, Cherie Abraham, and Kris Braman, which appeared in UGA's Landscape Alert Newsletter, explains that these pests typically just make the lawn look ragged.
However, it adds that "newly sodded or sprigged areas can be more severely damaged or even killed."
It goes on to explain that some grasses are more susceptible to damage than others:
"At least some cultivars of all warm season grasses are susceptible. Cool season grasses like tall fescue are very favorable for fall armyworm growth and development too, and do not regenerate as readily as the stoloniferous grasses."
Armyworms tend to be more active late in the day and at night, so they might not be readily apparent when a homeowner is out looking at a damaged lawn during the day.
A 2012 Georgia FACES article by Adam Speir on fall armyworms mentions that an inverted Y-shape on the head of the caterpillar is an identifying feature, and that these caterpillars also can cause considerable damage to agricultural fields.
For lawns as for fields, scouting for the pests if their presence is suspected can prevent a lot of potential damage. For homeowners, this is the recommendation for finding the armyworms: "If there is any doubt about whether worms are present, pouring soapy water on the grass (1/2 oz. dishwashing soap/gallon water) will bring them up very quickly. Heavily infested turf will also have visible greenish-black fecal pellets on the soil surface. Other indicators of armyworm infestations may include birds or even paper wasps that use the fall armyworms as food."
For fuller explanations of the lifecycle or control recommendations for this pest, read the above-linked articles or check with your local extension office.