Something Is Eating My Brussels Sprout Plants

Cabbage Worms

• Cabbage worms eat through Brussels sprout leaves, causing complete defoliation. It is important for gardeners to monitor their Brussels sprout plants in the spring for the presence of the white and brown moths that fly around at night. These moths lay eggs that later hatch into the larvae that eat Brussels sprouts. To control your cabbage worm population, spray your Brussels sprout plants with a pesticide that contains permethrin, as recommended by Ohio State University.

Aphids

• Aphids are nutrient-sucking insects that suck the sap out of Brussels sprout foliage. Gardeners with an aphid infestation may notice leaves turning yellow, curling and defoliating. In addition, aphids produce a sticky substance called honeydew, which coats the entire Brussels sprout plant. Fungal spores that cause sooty mold disease stick to the honeydew. The result is a powdery substance covering leaves, which inhibits the plant's ability to photosynthesize. Control aphids by spraying your Brussels sprouts with an insecticidal soap.

Flea Beetle

• Flea beetles cause "shothole" looking bite marks on Brussels sprout foliage. Brussels sprout seedlings are at the greatest risk of damage, because severe flea beetle damage stunts growth. You may notice flea beetles by their tiny, shiny bodies jumping around on your Brussels sprout crop. Gardeners may use cultural control practices by vacuuming flea beetles off of crops, as suggested by the University of Colorado. Use an insecticide that contains carbaryl, spinosad, bifenthrin or permethrin to control flea beetles.

Cabbage Loopers

• Cabbage loopers are 2-inch green caterpillars that invade Brussels sprouts. Crops infested with cabbage loopers display leaf skeletonization and defoliation, according to Texas A&M University. Gardeners may notice Brussels sprout damage in the spring right after eggs have hatched caterpillars. These pests are able to overwinter in plant debris left in the garden. To prevent future cabbage looper problems, remove all debris before winter. Spray Brussels sprout plants with an insecticide when you first see their damage.