Cabbage Looper - Knowledgebase Question

Name: Mary Cartelli-Joynt
Newport Beach, CA
Question by mcartelli
September 16, 2004
I have Cabbage Loopers noshing away on my broccoli plants....what can I do to control them without using a pesticide that could be harmful to those consuming the veggies when they are ready for harvest? I've read about Bacillus thuringiensis as effective control, but is it safe to use on vegetables and herbs?

Answer from NGA
September 16, 2004


From cabbage to Brussels sprouts, broccoli, cauliflower and kale, all of these cole vegetables are susceptible to the same pests -- namely the cabbage worm! This pesky worm makes it appearance in early spring when the cabbage white butterfly lays small yellow eggs on the leaf undersides of cabbage family crops. The eggs hatch into green leaf-eating caterpillars that grow up to 2 inches long. Although cabbage worms are most prevalent in late spring, they can cause damage in late summer, as well.

The easiest way to rid your cole crops of cabbage worms is by handpicking the bugs from the leaves. If cabbage worms have become too numerous to hand pick, treat the plants with an insecticide that contains Bacilulus thuringiensis, called BT, a naturally occurring bacteria that is harmless to humans but can destroy the insects.

You should apply BT in liquid form to all parts of the leaves, especially the undersides. Be sure to repeat the application after a rain. Apply the BT to the affected plants at 3 to 14 day intervals until the pest is removed. It takes about 5 to 6 days to eliminate the worms.

BT is safe to use on vegetables and herbs; be sure to read and apply in accordance with label directions.

Another good natural method for controlling all sorts of pests, including the cabbage worm, is insecticidal soap. The soap is a mixture of salts and fatty acids derived from plants. It is harmless to plants and works by drying up the pest causing it to die. You can apply the spray in the early morning or late afternoon, or on a cloudy day, while it's still cool, to reduce the risk of any possible damage to the plants and to minimize evaporation.

Best wishes with your veggies!

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