Practice Organic Cabbage Worm Control for a Chemical-Free Garden

Cabbage worms beat brassicas and consume cauliflower like nobody’s business. To defeat this garden pest, you must first learn how to identify it and then invite its natural enemies to live in your garden. Trust us, these neighbors won’t get along.


| March 25, 2013



Cabbage Worm Moth Illustration

If you see these little white butterflies in your garden, take action to protect your brassicas before the cabbage worm moths lay eggs.


Illustration By Keith Ward

This article is part of our Organic Pest Control Series, which includes articles on attracting beneficial insects, controlling specific garden pests, and using organic pesticides. 

Cabbage Worms (Pieris rapae

The most common of cabbage pests are cabbage worms, which are caterpillars of various butterflies and moths such as the one shown above. They feed on the leaves and heads of cabbage, broccoli, and closely related crops. Cabbage worms weaken plants by removing plant tissue, and they can ruin beautiful heads of cabbage or broccoli by boring inside. Organic controls for cabbage worms include handpicking, excluding them with row cover barriers, or treating with a Bt pesticide. Cabbage worms are found throughout North America, and more than one species may be found in the same garden. 

What Are Cabbage Worms? 

These three types of cabbage worms are frequent cabbage pests:

Imported Cabbage Worms. The most common species in home gardens are properly called imported cabbage worms (Pieris rapae). The larvae of an ever-present white butterfly with black spots, imported cabbage worms are native to Europe. They were first seen in North America in 1860 and are now established from Canada to California. Velvety green with faint yellow stripes, imported cabbage worms feed on all members of the cabbage family, especially cabbage, broccoli and cauliflower.

Cabbage Loopers. If the cabbage pest in question is a green to yellow-green slender caterpillar that raises up on its back as it moves, like an inchworm, it is likely a cabbage looper (Trichoplusia ni). Cabbage loopers have no legs in their midsection. The larvae of a small mottled night-flying moth, cabbage loopers may also be found feeding on many other garden plants. Unlike imported cabbage worms, they are not exclusively cabbage pests.  

Diamondback Moths. A third green cabbage worm sometimes caught rasping translucent windows in leaves, the larvae of diamondback moths (Plutella xylostella) are an occasional cabbage pest, often seen on turnips and mustard as well. Very small green worms less than a half inch long with two nubby legs extending from the tail end are the larvae of diamondback moths. 





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