WSU Extension


Common Insects & Mites : Cutworms and loopers
(revision date: 7/10/2015)

Cutworms and loopers are the larval stages of moths in the family commonly referred to as "millers". They are usually hairless caterpillars and exhibit wide variation in color and markings. In addition to six true legs, cutworms have a full complement of prolegs on their abdomens, usually 4 or 5 pairs. Loopers also have six true legs, but have fewer prolegs (often only 2 or 3 pairs at the back of the abdomen) which causes them to move in a characteristic inching or looping fashion. Cutworms are largely nocturnal and may often be found in soil around the base of their chosen food plant during the daytime. Loopers can often be found feeding during the day. The food of these caterpillars varies. For many, the primary host plants are native weeds, but in the absence of these they will feed on a wide variety of vegetables, fruits, and ornamentals. Damage is frequently seen in seedling vegetables and flowers as plants cut off at or just below the soil line. There are also climbing cutworms which chew leaves. There are hundreds of species of these caterpillars. Their feeding damage is quite generic and without seeing them do the damage, it can be difficult to diagnose the pest that is responsible. Damage can resemble that of sawfly, earwig and other chewing pests.
Management Options

Non-Chemical Management
  • Picking the caterpillars off the foliage and destroying them may be a useful alternative.
  • Encourage natural enemies of cutworms including birds and spiders.
  • Cutworms are largely night feeders. Determine if cutworms are doing the damage by going out after dark with a flashlight to find the pest.
Select non-chemical management options as your first choice!

Chemical Management

If nonchemical management options do not give satisfactory control, several insecticides and some biologicals are effective in managing these caterpillars. Make certain that the product that you purchase is registered for the target host and effective against the pest insect. Find a list of registered pesticides for a specific host by referring to the fact sheet for cutworms or loopers on that host.

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Caption: Spotted cutworm
Photo by: K. Grey
Caption: Western yellow stripe armyworm
Photo by: Unknown
Caption: Alfalfa looper and damage
Photo by: A.L. Antonelli
Caption: Bertha armyworm
Photo by: K. Grey
Caption: Dahlia cutworm
Photo by: A.L. Antonelli
Caption: Redhumped caterpillars
Photo by: A.L. Antonelli
Caption: Redbacked cutworm
Photo by: K. Grey
Caption: Looper on rhododendron
Photo by: S.J. Collman
Caption: Variegated cutworm larvae
Photo by: A.L. Antonelli
Caption: Western yellow stripe armyworm adult
Photo by: A.L. Antonelli
Caption: Celery looper pupa
Photo by: A.L. Antonelli
Caption: Cutworm eggs
Photo by: A.L. Antonelli
Caption: Alfalfa looper adult
Photo by: OSU slide library
Caption: Redhumped caterpillar adult
Photo by: A.L. Antonelli
Caption: Adult moth of the spotted cutworm, Xestia c-nigrum
Photo by: M. Bush