How to Manage Pests

UC Pest Management Guidelines

DESCRIPTION OF THE PESTS

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**	P.H.I.+
(trade name)			(days)
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy and impact on natural enemies. Also consider information relating to water quality when choosing a pesticide.
A.	PERMETHRIN*
	(Ambush) 25W	6.4–12.8 fl oz	1
	MODE OF ACTION: A pyrethroid (Group 3)1 insecticide.
	COMMENTS: Apply as a foliar application before brown silk stage. Do not apply more than 1.2 lb a.i./acre/season.
B.	CHLORPYRIFOS*
	(Lorsban) 4E	1–2 pt	Grain or livestock feed: 35
			Grazing or silage: 14
	MODE OF ACTION: An organophosphate (Group 1B)1 insecticide.
	COMMENTS: Not for use on popcorn. Avoid drift and tailwater runoff into surface waters. Do not apply more than 6 pt/acre/season. Do not make more than 3 applications/season.
C.	CARBARYL
	(Sevin) 5% Bait	40 lb	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. + Preharvest interval. Do not apply within this many days of harvest. * Permit required from county agricultural commissioner for purchase or use.   1 Modes of action are important in preventing the development of resistance to pesticides. 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. 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 is assigned by IRAC (Insecticide Resistance Action Committee). For additional information, see their Web site at http://www.irac-online.org/.

PUBLICATION

UC IPM Pest Management Guidelines: Corn
UC ANR Publication 3443
Insects and Mites
L. D. Godfrey, Entomology, UC Davis
S. D. Wright, UC Cooperative Extension, Tulare County
C. G. Summers, Kearney Agricultural Center, Parlier
C. A. Frate, UC Cooperative Extension, Tulare County
Acknowledgement for contributions to the Insect and Mites section:
M. J. Jimenez, UC Cooperative Extension, Tulare Co.

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