Broccoli and cauliflower belong to the cole crop family, which also includes cabbage, collard greens, kale, radishes, turnips and mustard. Unfortunately, when grown in vegetable gardens, these plants all have problems with insects eating them.
Many types of insects eat broccoli and cauliflower. Cabbage worms, aphids, cutworms, cabbage maggots, caterpillars, flea beetles and diamondback moths all infest and damage broccoli and cauliflower crops. In some areas, deer also munch on these crops from vegetable gardens.
Insect infestations often cause severe damage to the plant leaves as they eat the plants. The University of Minnesota Extension explains that cabbage maggots can eat cole crop roots, killing or severely damaging the health of the entire plant. All types of insect or animal pests that eat cabbage and broccoli reduce yields and make the crops less attractive.
Gardeners can keep deer away from cabbage and broccoli with mesh netting or tall fences around the vegetable garden. Gardening stores sell ladybirds, which feed on aphids and other insect eggs. The University of Minnesota Extension and University of Florida Institute of Food and Agricultural Sciences both suggest using an insecticide carefully in accordance with the package instructions to get rid of severe infestations.