Insect of the Week: the Cabbage Looper

Adapted from pages 102-103 of Garden Insects of North America:

Despite its name, the cabbage looper is not limited to mustard family plants but may also damage plants as diverse as potatoes, tomatoes, peas, lettuce, spinach, nasturtium, and carnation. It is sometimes found as a greenhouse pest on various ornamentals. Larvae chew leaves of various plants, occasionally causing serious defoliation. Late instars tend to tunnel into heads of cabbage, lettuce, and other plants, causing additional injury.

An adult cabbage (Trichoplusia ni) looper feeding at a flower. Photo credit: Whitney Cranshaw.

The Cabbage Looper thrives best in warmer climates and survives poorly following winters in areas with extended freezing temperatures. Adults, however, are strong fliers and annually migrate long distances. Caterpillars are pale green, darkening somewhat as they get older. Faint white stripes run the length of the body. Adults are of moderate size (wingspan of about 1.5 inches) with mottled gray or brown forewings and a distinctive silvery white U-mark with a single spot below.

Their eggs are hemispherical and glued singly to foliage, often in small groups. They hatch in a few days, and the first-stage larvae are creamy colored. They go through a series of molts as they develop, becoming full grown in about 3 weeks. Young larvae typically feed on outer leaves, producing windowpaning patterns on thick-leaved plants such as cabbage. Late stages feed more generally and tend to tunnel into heads. Pupation occurs on or in the nearby vicinity of host plants in a loose cocoon, and the pupal stage lasts 1–2 weeks. The number of generations produced annually is highly variable, and during the growing season generations greatly overlap and become indistinct.

Head to our Instagram to see the evolution of the Cabbage Looper, from egg to adult.

Garden Insects of North America: The Ultimate Guide to Backyard Bugs
Second Edition
By Whitney Cranshaw & David Shetlar

This second edition of Garden Insects of North America solidifies its place as the most comprehensive guide to the common insects, mites, and other “bugs” found in the backyards and gardens of the United States and Canada. Featuring 3,300 full-color photos and concise, detailed text, this fully revised book covers the hundreds of species of insects and mites associated with fruits and vegetables, shade trees and shrubs, flowers and ornamental plants, and turfgrass—from aphids and bumble bees to leafhoppers and mealybugs to woollybears and yellowjacket wasps—and much more. This new edition also provides a greatly expanded treatment of common pollinators and flower visitors, the natural enemies of garden pests, and the earthworms, insects, and other arthropods that help with decomposing plant matter in the garden.

Designed to help you easily identify what you find in the garden, the book is organized by where insects are most likely to be seen—on leaves, shoots, flowers, roots, or soil. Photos are included throughout the book, next to detailed descriptions of the insects and their associated plants.

An indispensable guide to the natural microcosm in our backyards, Garden Insects of North America continues to be the definitive resource for amateur gardeners, insect lovers, and professional entomologists.

  • Revised and expanded edition covers most of the insects, mites, and other “bugs” one may find in yards or gardens in the United States and Canada—all in one handy volume
  • Features more than 3,300 full-color photos, more than twice the illustrations of the first edition
  • Concise, informative text organized to help you easily identify insects and the plant injuries that they may cause


This post is part of a series, explore additional posts here<< Insect of the Week: the Buffalo TreehopperInsect of the Week: Leaf miners >>