Fall armyworms attack lawns, golf courses in Virginia

By Tom Kuhar, Alejandro Del Pozo and Sally Taylor
This fall, some Virginia County Extension (VCE) agents as well as golf course superintendents in the north central and southwestern counties of Virginia have reported fall armyworm outbreaks on lawns and golf courses — including many lawns in the West End of Henrico. This outbreak is earlier than usual and potentially could lead to one of the heaviest pest problems that we’ve experienced from this pest in Virginia. Some lawns have completely been destroyed by these voracious feeders.

It’s important to understand the biology of this polyphagus pest. Fall armyworm (Spodoptera frugiperda) is a tropical moth native to warm climate areas of the western hemisphere. It cannot successfully overwinter in Virginia. However, fall armyworm moths are strong fliers, and populations can show up throughout the eastern United States in the late summer and fall months, sometimes in very high populations like we saw most recently in 2018 in Virginia. Female FAW moths can lay up to 10 egg masses (each with 100 ‐ 200 eggs). So, huge densities of armyworms can build up from just a few egg laying moths in a field. This can completely destroy lawns or new plantings of grain cover crops. Fall armyworm can feed on a number of different host plants, but prefers grasses, small grains, corn and sorghum.

Insecticides recommended for control include most pyrethroids (such as bifenthrin, lambda‐cyhalothrin, Mustang Max, Baythroid XL, etc..), the carbamate, Lannate LV, and many of the more selective (lepidopteran‐targeting) insecticides such as the diamide Prevathon, Coragen, Acelepryn, Besiege), indoxacarb products like Steward, Avaunt eVo, Provaunt, spinosad (Blackhawk, Tracer, Matchpoint), Radiant, Intrepid Edge, as well others. Consult the relevant Pest management Guide for specific recommendations on the various commodities.

Please note that control of large larvae is sometimes difficult with any insecticide. Links to the VCE Pest Management Guides for Field Crops, Vegetables and Turf are provided below. On
turf, we have gotten very good control of FAW larvae with pyrethroids, which are also one of the cheaper insecticide options.
Links to Pest Management Guides: https://resources.ext.vt.edu/
Turf: https://resources.ext.vt.edu/contentdetail?contentid=2706&contentname=2021%20Home%20Grounds%20PMG%20-%20Lawn
Field Crops: https://resources.ext.vt.edu/contentdetail?contentid=2375&contentname=2021%20Pest%20Management%20Guide%20‐%20Field%20Crops
Vegetables: https://resources.ext.vt.edu/contentdetail?contentid=2379&contentname=2020‐2021%20Mid‐Atlantic%20Commercial%20Vegetable%20Production%20Recommendations
In Sources: http://entnemdept.ufl.edu/creatures/field/fall_armyworm.htm
Luginbill P. 1928. The fall armyworm. USDA Tech. Bull. No. 34.