From stews to coleslaws to sandwiches, green and purple cabbage can be found in more than just sauerkraut. Cabbage—a cool-season crop grown throughout Florida—is one of many cruciferous vegetables or cole crops.
Florida ranks third for fresh-market cabbage production nationally, so local farmers should know about possible threats to cabbage crops and how to manage them.
Aphids are soft-bodied pests that can spread viruses. Throughout the year, female aphids give birth to live insects, which mature in 7–10 days. The newborn pests pierce the plant with their needle-like mouths, sucking the plant’s juices. This causes the leaves to curl and yellow, or, if the cabbage is a seedling, to become stunted and die.
Rather than using pesticides, natural enemies–lacewing larvae, ladybeetles, and syrphid fly larvae—can manage aphids. Controlling weeds, investigating the crop, killing plant remains, and adding a nectar source for predators can help control aphids as well.
The beet armyworm attacks cabbage and many other vegetables, such as asparagus, beet, cauliflower, celery, onion, pepper, and tomato. A female armyworm can lay up to 600 eggs, and its larvae feed on both fruit and foliage.
Field hygiene techniques—such as scouting for feeding caterpillars, field disking, using pheromone traps, and destroying infested crops—can help control pests. Because natural enemies cannot fully prevent crop loss, insecticides can be used to regulate young instars.
Although the cabbage looper is considered a minor pest in South Florida, it is one of the most significant pests for Florida cabbage growers each year. Larvae chew holes in the leaves and dig into the cabbage head, damaging plants and leaving them unmarketable at times.
Because the cabbage looper thrives in temperatures greater than 80°F, it’s best to plant cabbage during cooler months. Fields should be scouted weekly to see if pests are present, and Bt insecticides, which occur naturally in soils, can kill the pests.
Cutworms—black cutworm and granulate cutworm—are thick, gray caterpillars that burrow in soil during the day and feed at night. Although they attack plants in one row, adults that fly into the field are the most mobile. The large moths lay eggs on plants, and then the hatched larvae eat the cabbage’s leaves, stems, and head.
Inspecting crops twice a week can control damage, and adults can be found using a black light and pheromone traps. If spraying insecticides, post-emergence applications work best, and natural enemies—parasitic wasps, ground beetles, and flies—can control nearly 80% of the pests.
Since the 1980s, the diamondback moth has been the predominant pest on Florida cabbage. The slender, grayish-brown moths lay eggs, which hatch within one day on cabbage leaves. Larvae then feed on leaves, creating small holes, and eat cabbage heads, causing deformation and decay.
Like the cabbage looper and beet armyworm, planting cabbage from September to April will help avoid diamondback moth infestation. The pests can also be managed by scouting the fields weekly and using a parasitoid wasp to serve as the larvae’s natural enemy.
Adapted and excerpted from:
S. E. Webb, “Insect Management for Crucifers (Cole Crops)” (ENY464), UF/IFAS Entomology & Nematology Department (rev. 06/2013).
W. M. Elwakil and M. Mossler, “Florida Crop/Pest Management Profile: Cabbage” (CIR1256), UF/IFAS Agronomy Department (rev. 04/2013).