Parasites, diseases, insect predators, and birds usually keep armyworms under control in small grains. However, the effectiveness of these natural control agents is reduced during cool, wet springs and during growing seasons that follow years of drought.
Armyworms should be detected while they are still small and easier to control. Check fields once each week starting the second week of May. Examine first the debris and undergrowth on the ground surface along field margins and lodged areas. Small worms usually are found curled in a C-shape around the base of the plants or under the debris and winter annual weeds. Armyworm frass or droppings also may be found on the soil surface. If small armyworms are present in these areas, obtain 10 to 20 worm counts at 50-pace intervals throughout the field. Note the average size of the worms and whether any defoliation of the flag leaf or head clipping has occurred.
As a general rule, barley should be treated if the number of armyworms exceeds one per linear foot between rows and most of the worms are greater than 0.75 inch long. In wheat, armyworms tend to nibble on the tips of kernels rather than clip heads; thus, populations around two to three worms per linear foot between rows are required to justify control. In high-management wheat fields with 4-inch rows, treatment is recommended when armyworm levels exceed three to five per square foot of surface area.
Note that wheat fields with mixed infestations of armyworms and sawfly caterpillars may need treatment even if worm counts of each pest do not exceed threshold levels. Also, if the grain crop is close to harvest or the majority of armyworms are longer than 1.5 inches and no head clipping has occurred, control may not be needed.
You are viewing records 1 - 5 of 8. Next 3 Records| Insecticide and formulation | Rate of active ingredient per acre | Rate of formulation per acre | Time lmits: Days before harvest | Remarks |
|---|---|---|---|---|
| carbaryl (Sevin XLR Plus) |
1.0-1.5 lb | 2.0-3.0 pt | 21 | Wheat Only. |
| lambdacyhalothrin (Lambda-Cy 1EC) |
0.02-0.03 lb | 2.56-3.84 fl oz | 30 | Restricted Use: Barley, Oats, Rye and Wheat. |
| lambdacyhalothrin (Warrior II) |
0.02-0.03 lb | 1.28-1.92 oz | 30 | Restricted Use: Barley, Oats, Rye and Wheat. |
| methomyl (Lannate 2.4LV) |
0.23-0.45 lb | 0.75-1.5 pt | 7 | Restricted Use: Barley, oats, rye and wheat. |
| microencapsulated methyl parathion (Penncap-M 2F) |
0.5-0.75 lb | 2.0-3.0 pt | 15 | Restricted Use: Barley, Oats and wheat. |
