Garden pest
Cabbage worms & loopers
Velvety green caterpillars that chew brassicas into lace.
Cabbage worms & loopers is in its active season now — scout your plants this week.
How to identify cabbage worms & loopers
Two look-alikes get lumped together. The imported cabbage worm is a fuzzy, pale-green caterpillar that rests along a leaf midrib; its parent is the small white butterfly you see fluttering over the garden. The cabbage looper is smooth green with thin white side stripes and 'loops' its back as it crawls.
Both blend into the leaf, so the frass and holes usually give them away before the caterpillar does. Check deep in the heart of the plant where they hide.
Attacks: Cabbage, Broccoli, Kale, Cauliflower, Brussels sprouts, Collards
Life cycle: White or gray moths lay single eggs on leaf undersides; caterpillars feed 2-3 weeks then pupate on the plant. Several overlapping generations run from spring through fall.
Signs of cabbage worms & loopers
What you actually see on the plant — usually before you spot the pest itself.
- Ragged holes chewed through leaves, worst in the center of the head
- Dark green pellet droppings collecting in the leaf folds and crown
- Tunneling into broccoli and cabbage heads that shows up at harvest
Organic control, least-toxic first
Start at the top and only move down if you need to. Physical and cultural fixes come before any spray.
- Float a row cover from transplant day
Fine insect netting over hoops keeps the egg-laying moths off entirely. Brassicas don't need pollinators, so you can leave the cover on all season.
- Hand-pick and squash eggs
Check leaf undersides a couple of times a week and rub off the bullet-shaped yellow eggs and any caterpillars you find.
- Spray Bt on the leaves
Bt is very effective on young cabbage worms and harmless to bees and people. Spray both sides of the leaves and reapply after rain, per the label.
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One rule for any product you spray: follow the label. The label is the law, and it is the tested, safe rate for your plants — homemade mixes and dish-soap sprays are not, and can scorch foliage.
Prevent it next season
- Cover new transplants before the white butterflies find them
- Pull and compost spent brassica stumps where late caterpillars overwinter
- Rotate brassicas and interplant flowers to feed the parasitic wasps that hunt them
Questions about cabbage worms & loopers
How do I get rid of cabbage worms organically?+
Cover plants with insect netting so the butterflies can't lay eggs, hand-pick the caterpillars and eggs you find, and spray Bt on any that slip through — it's safe on food crops.
Are the green worms on my kale safe to eat off?+
They won't hurt you, but soak harvested leaves in cold salted water for a few minutes to float out any hidden caterpillars before cooking.
Plan a garden that fights back
Healthy, well-spaced plants shrug off pests that flatten a crowded bed. PlotToTable sizes your beds, spaces every crop, and flags the pests that hit what you grow.