The adult moths or butterflies sip nectar from flowers and dont cause damage as the larvae do.
What Do Cabbage Worms Look Like?
The adultsbutterflies or mothsfeed on nectar and lay eggs on host plants.
The Spruce / Jiaqi Zhou
The pupae metamorphoses into adults and the life cycle starts again.
They have a wingspan of roughly 2 inches.
The adults lay their eggs both on the upper side and the undersides of leaves.
Butterfly of the Imported cabbage worm (Pieris rapae)Photos from Japan, Asia, and of the world / Getty Images
The eggs are yellow and oval-shaped.
They feed on the host plants for about 15 days and move slowly when disturbed.
There are about two to three generations per year.
Larva of imported cabbage worm feeding on a cabbage leafribeiroantonio / Getty Images
They have mottled grayish-brown wings with a 1.5-inch wingspan.
They lay their eggs on the undersides of the lower leaves of host plants.
The eggs are creamy white and about the size of a pin head.
Cabbage looper moth (Trichoplusia ni)Valter Jacinto / Getty Images
The larvae are pale green with thin white stripes lines running down each side of the body.
The mature larvae are about 1.5 inches long.The larvae have no legs in their middle section.
The feed on plants for two to four weeks.
Larva of the cabbage looper mothsamuel howell / Getty Images
When they move, they make a looping motionthey have no legs in their middle sectionhence their name.
The number ofgenerationsranges from two to three in cold climates to five to seven in hot climates.
They are named after the white diamond pattern on their folded wings.
Diamondback moth (Plutella xylostella)Ian_Redding / Getty Images
They lay their tiny, cream-colored eggs near the leaf veins.
The larvae are light green and tapered.
When disturbed, they wiggle back and forth so rapidly that they often drop off the plants.
Larvae of the diamondback moth (Plutella xylostella)Tomasz Klejdysz / Getty Images
How many days the larvae feed depends on the availability of food and the temperature.
The earlier you catch and get rid of them, the better.
Treatment is always for the larval stage, not the adult moths or butterflies.
Treating Minor Populations
If there are just a few worms, hand-picking can take care of them.
Collect them in a pail of soapy water to kill them.
Another treatment for a minor population of cabbage worms isneem oil.
While you wont kill the insects directly, it prevents them from feeding on your plants.
However, keep in mind that this abrasive substance also kills other beneficial insects.
see to it to follow the product label.
Their green color can make them difficult to spot especially when they first hatch out and are very small.
As with all caterpillars, they will get bigger as they defoliate and devour your crop.
What Causes Cabbage Worms?
Imported cabbageworms overwinter as pupa or chrysalis in plant debris and emerge as adults in the spring.
The cabbage loopers overwinter in the south and the adults migrate north in mid-summer.
Cabbage worms have several natural enemies, including paper wasps, parasitic flies, and wasps that kill them.
It will expand as the cabbage grows so you’re free to leave it on until harvest.
The holes that the worms chew in leaves are only an aesthetic issue, the leaves are still edible.
It depends what species it is whether cabbage worms turn into butterflies or nocturnal moths.
The most commonly known is the cabbage white butterfly, which is the adult of the imported cabbageworm.
There are several insecticides that are derived from naturally occurring substances, such as Bt.
Cabbage Looper.Wisconsin Horticulture,
Cabbage Worms and Cole Slaw.
National Pesticide Information Center.
Caterpillars on Cole Crops in Home Gardens.
University of Minnesota Extension.
