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.
Thresholds
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 |
|
|
Insecticide |
Rate |
|
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
Disclaimers
This content may not be suitable for states other than Kansas.
