Pest known to damage cole crops such as broccoli, brussels sprouts, cabbage, cauliflower, collards, kale, and kohlrabi. Adults are nocturnal moths with brown, speckled fore wings that have a tiny, silver figure-eight-shaped patch in the center.
Their eggs are spherical, ridged, tiny, and have a greenish-white hue. The larvae are easily recognized by their movement because they move like inchworms and have the distinctive "looping" motion. The larvae are green with white stripes spanning the length of their bodies. Near its head, the caterpillar has three pairs of slender legs, and then near the end of its body, it develops three pairs of thick prolegs. 

Loopers eat ragged holes in leaves and bore through heads, which enhance the plant's vulnerability to disease. Late spring and summer, as well as late fall on occasion, are typically the months with the highest populations. 

Think Preventative 

A crucial component of preventive and control is inspection. Keep an eye out for any evidence of pests on the plants and in the growth environment, particularly the medium. Adults or visible egg clusters should be manually removed and disposed of. You can use soap water to drown the larvae.

Use general predators to monitor and detect infestations early. When using beneficial insects for natural organic pest control it is a good practice to be preventative. Release predators like Ladybugs or Green Lacewings early and regularly throughout the growing seasons before you have an infestation. They will eat the eggs and prevent an infestation.

Release Trichogramma parasitic wasps to disrupt the life cycle of the looper and stop further generations from becoming a problem.

Other alternatives to beneficial insects that can be used to control Cabbage Looper include:

Cabbage Looper traps can be used to attract and kill adult males and stop them from mating.