Most damage to wheat in Kansas occurs in southern and eastern areas of the state during warm, moist periods from late April to early June. Each larva, feeding mostly at night, can consume 43 linear inches of wheat leaf, or the equivalent of three whole plants, in the course of its development. However, 80 percent of this damage occurs during the last three to five days of larval feeding.
When leaf feeding is observed, look for larvae curled up on the ground under litter, especially in patches of lodged plants. Treatment is usually not necessary below levels of four or five larvae per foot, but is probably justified at infestations of five to eight per foot provided most larvae are still small.
Wheat is likely to suffer yield loss if the flag leaf is destroyed before the soft dough stage is completed. Plant developmental stage is a factor to consider when making treatment decisions. As wheat plants mature and leaves dry out, armyworms may feed on beards and clip heads to complete their development. Head clipping in barley is serious and should be prevented. While it is less likely in wheat, worms should be watched closely if present after heading and forced to feed on the upper parts of plants to complete development.
None listed.
This content may not be suitable for states other than Kansas.
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Armyworm Management Options |
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Insecticide |
Rate |
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Alpha-cypermethrin (Fastac EC) |
1.8 to 3.8 fl. oz./acre |
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Beta-cyfluthrin (Baythroid XL) |
0.014 to 0.019 lb. a.i./acre (1.8 to 2.4 fl. oz.) |
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Carbaryl (Sevin 80S) |
1.25 to 1.625 lb./acre |
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Chlorantraniliprole (Prevathon) |
0.047 to 0.067 lb. a.i. per acre or 14 to 20 fl. oz. per acre |
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Chlorpyrifos plus gamma-cyhalothrin (Cobalt Advanced) |
11 to 25 fl. oz./acre |
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Chlorpyrifos plus zeta-cypermethrin (Stallion) |
9.25 to 11.75 fl. oz./acre |
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Gamma-cyhalothrin (Proaxis) |
0.01 to 0.015 lb. a.i./acre (2.56 to 3.84 fl. oz.) |
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Lambda-cyhalothrin (Numerous products) |
0.02 to 0.03 lb. a.i./acre |
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Spinosad (Blackhawk) |
0.025 to 0.050 lb a.i./acre (1.1 to 3.3 fl. oz/acre) |
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Zeta-cypermethrin (Mustang MAXX, etc.) |
0.011 to 0.025 lb. a.i./acre (1.76 to 4.0 fl. oz.) |