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Homemade Spray for Broccoli Worms

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Broccoli grows readily in the home garden, producing clusters of fresh-tasting broccoli. Small, green broccoli or cabbage worms, flea beetles and aphids are among the pests that may bother broccoli. Use a homemade concoction containing pest-deterring onion, garlic and pepper for all leaf-eating insects, or try other organic methods of pest control.

Homemade Spray

Puree one small onion, one clove of garlic, 1 tsp. cayenne pepper and 1 qt. water in a blender. Wait one hour for the mixture to steep. Strain through cheesecloth to remove solids. Add 1 tsp. liquid dish soap and pour the solution into a spray bottle. Spray the solution on broccoli leaves, coating the undersides of the leaves as well as the tops. Refrigerate the solution for up to one week. This mixture may cause eye or skin irritation. Wear gloves when handling. According to Washington State University, homemade concoctions are not registered with the U.S. Department of Agriculture, and they are technically illegal to use on crops. They have not been found to be effective in controlled studies, although they may provide some protection in individual gardening situations.

Mechanical Methods and Barriers

Lay floating row covers, made of lightweight agricultural fabrics, over the soil after planting broccoli seeds. Floating row covers allow sunlight and rain through but keep insects out of the garden. They also provide insulation from cold temperatures, hastening germination. Remove them to weed, thin and harvest the broccoli. Handpick cabbage worms and drop them in a bucket of soapy water.

Organic Pesticides

Bacillus thuringiensis, or Bt, a bacterial disease organism, kills all kinds of caterpillars and worms by attacking the lining of the gut, causing the insect to starve. It is completely safe for humans and wildlife, and it doesn't harm beneficial insects. Spray the leaves thoroughly with Bt. Once the cabbage worms eat the sprayed leaves, they die within two to four days, although they stop feeding on leaves almost immediately. Spray aphids and flea beetles with an insecticidal soap.

Natural Predators

Ladybugs and lacewings dispatch aphids and flea beetles, but they are too small to take on cabbage worms. However, birds, garter snakes and frogs eat cabbage worms. Plant flowering herbs, such as dill or parsley, to attract beneficial insects and provide a water source, such as a bird bath or bowl of water, nearby.

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