Description of the Pest
Adults are moths approximately 1 inch long with a wing span of 1.25 to 2 inches and vary widely in coloration. Eggs are somewhat flattened on top, white to dull or off-white in color, and ribbed. They are generally deposited in massed rows. Eggs may be deposited on crop foliage, but are frequently found on weeds. Fully grown larvae range from 1 to 1.75 inches in length and commonly curl into a C-shape when disturbed.
Cutworms are most active and cause the most damage during spring and early summer months. The larvae normally hide under debris on the soil surface during the day, but are active, voracious feeders at night. Some cutworms climb into the host plant to feed, but many stay on the ground, cutting seedling host plants off at or just below the soil surface.
Damage
Cutworms cut young plants off at the base or near the ground level. Usually, it is necessary to dig in the soil to find cutworm larvae and to determine the extent of the infestation and the size of the cutworms involved.
Management
If the cutworm population is reducing the plant stand, treat during the seedling stage. Frequently, the damage is most serious at the edges of a field, but stand loss can occur in a spotty pattern throughout the field. Treatment of hot spots may be possible. Seedlings will regrow if damage is above the growing point.
Organically Acceptable Methods
Eliminating weeds 2 weeks before planting both within and adjacent to the field can help to minimize cutworm problems in an organically managed crop.
| Common name | Amount/Acre** | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (hours) | (days) | ||
| Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least harmful to natural enemies, honey bees, and the environment are at the top of the table. When choosing a pesticide, consider information relating to air and water quality, resistance management, and the pesticide's properties and application timing. Always read the label of the product being used. | ||||
| A. | PERMETHRIN* | |||
| (Ambush) 25W | 6.4–12.8 fl oz | 12 | 1 | |
| MODE OF ACTION GROUP NUMBER1: 3 | ||||
| COMMENTS: Apply as a foliar application before brown silk stage. | ||||
| B. | CARBARYL | |||
| (Sevin) 5% Bait | 40 lb | 12 | see label | |
| MODE OF ACTION: A carbamate (Group 1A)1 insecticide. | ||||
| COMMENTS: Ground or air application. Use only fresh bait. Apply in late afternoon or early evening so bait stays fresh longer. Avoid direct application to lakes, streams, ponds. Do not apply when weather conditions favor drift from treated areas. Do not contaminate water, food, or feed when cleaning equipment or disposing of wastes. | ||||
| ** | Mix with sufficient water to obtain full coverage. |
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest. |
| * | Permit required from county agricultural commissioner for purchase or use. |
| 1 | Rotate chemicals with a different mode-of-action Group number, and do not use products with the same mode-of-action Group number more than twice per season to help prevent the development of resistance. For example, the organophosphates have a Group number of 1B; chemicals with a 1B Group number should be alternated with chemicals that have a Group number other than 1B. Mode of action Group numbers are assigned by IRAC (Insecticide Resistance Action Committee). |