Alfalfa Looper

Alfalfa Looper Life StagesAlfalfa Looper Life Stages

Minor Looper Feeding Damage and Frass on BroccoliLooper feeding damage and frass on broccoli.

Looper Feeding Damage on CabbageLooper Feeding Damage on Cabbage

Weeding the Garden to Reduce Pupae Overwintering SitesWeeding the garden reduces pupae overwintering sites.

HOSTS

  • Alfalfa
  • Leafy Greens
  • Legumes

DESCRIPTION

Adults have gray-silver forewings with ivory colored markings. Their wingspan is about 1 1/3 inches (35 mm). Alfalfa looper adult moths are notably brighter than cabbage looper moths. Eggs are pale yellow with thin vertical ridges. Larva are green with white line down the sides of their body and reach just over 1 inches (30 mm).

BIOLOGY

Egg | Larva | Pupa | Adult
Alfalfa loopers overwinter as pupa in the soil or plant residue on the ground. Adult moths emerge in the late spring and will lay eggs on weedy hosts. Once hatching, larvae can chew holes in leaves. Sometimes they can cause serious defoliation. As caterpillars mature, their feeding intensifies, and they often move into the developing heads. Larvae feed for about a month before pupating. There are three to four generations per year.

SYMPTOMS

  • Irregularly-shaped holes in foliage.
  • Skeletonized leaves.
  • Frass (fecal matter) on and within crops.

GENERAL MANAGEMENT

  • Hand remove caterpillars.
  • Use floating row covers.
  • Plant tolerant crop varieties.
  • Clean growing site of plant debris after harvest.
  • Manage weeds to remove overwintering sites for pupae. 

INSECTICIDES

Insecticides containing Bacillus thuringiensis var. kurstaki (Bt) and spinosad are effective in suppressing alfalfa looper larvae.



















Precautionary Statement: Utah State University and its employees are not responsible for the use, misuse, or damage caused by application or misapplication of products or information mentioned in this document. All pesticides are labeled with ingredients, instructions, and risks, and not all are registered for edible crops. “Restricted use” pesticides may only be applied by a licensed applicator. The pesticide applicator is legally responsible for proper use. USU makes no endorsement of the products listed in this publication.