Fall Armyworm (Kansas Wheat)

Scouting time

This moth does not overwinter in the Great Plains but migrates northward annually from southern states. It usually arrives in Kansas in July where it lays eggs on corn, sorghum and other summer crops. Several generations occur and reproduction may continue through August and into September, putting early-planted wheat at greatest risk.

Sampling method

Early-planted fields should be inspected frequently during the first few weeks following emergence. The first sign of damage is “windowpane” injury caused by tiny larvae chewing on seedling leaves. The larvae, which are usually too small to be easily observed at this time, hide in or around the base of seedlings. Within a few days the larvae become large enough to destroy entire leaves. Larvae increase in size at an exponential rate, and so do their food requirements. Later instars do the most damage, sometimes destroying entire stands, and are the least susceptible to insecticides.


Fields with 25 to 30 percent of plants with windowpane injury should be re-examined daily and treated immediately if stand establishment appears threatened. Without treatment, problems can continue until larvae reach maturity or until a killing frost.

Chemical control

Fall Armyworm Management Options



Alpha-cypermethrin (Fastac EC)

 3.2 to 3.9 fl. oz./acre

Beta-cyfluthrin (Baythroid XL)

 0.014 to 0.019 lb. a.i./acre (1.8 to 2.4 fl. oz.)

Chlorantraniliprole (Prevathon)

 14 to 20 fl. oz./acre

Chlorpyrifos plus zeta-cypermethrin (Stallion)

 9.25 to 11.75 fl. oz./acre

Gamma-cyhalothrin (Proaxis)

 0.01 to 0.015 lb. a.i./acre (2.56 to 3.84 fl. oz.)

Lambda-cyhalothrin (Numerous products)

 0.02 to 0.03 lb. a.i./acre

Spinosad (Blackhawk)

 0.038 to 0.050 lb a.i./acre (1.7 to 3.3 fl. oz/acre)

Zeta-cypermethrin (Mustang MAXX, etc.)

 0.02 to 0.025 lb. a.i./acre (3.2 to 4.0 fl. oz.)


Non-chemical controls

None listed.

Content authors


This content may not be suitable for states other than Kansas.