Organic Insecticide for Turnip Greens

Cabbage Aphid

• Cabbage aphids can be found in clustered masses that resemble white ash. Aphids suck the plant sap and deform the leaf. Once the aphids are sheltered by the curling, deformed leaves, they are particularly difficult to control. Several organic insecticides are approved to control cabbage aphids. Insecticidal soap can be used to control aphids but will not work if populations are high, so it is important to check regularly for aphids. Products containing neem oil, summer oils and kaolin clay can help to control aphids as well.

Cabbage Lopper, Diamondback Moths and Cabbage Worms

• Cabbage lopper, diamondback moths and cabbage worms are all members of the Lepidoptera family of insects. Their larval forms feed on the leaves and contaminate the foliage with fecal matter. These insects can have multiple life cycles per season, and your turnip greens should be checked regularly for their presence. Spinosad and Bacillus thuringiensis (BT) -- both bacterial insecticides -- are reported by Cornell University as having effective control. Several bacterial strains of BT are available, and they should be rotated to prevent resistance buildup. Neem oil is moderately effective and may require several applications.

Flea Beetles

• Flea beetles are small black beetles that chew holes in the leaves and reduce the marketability of fresh turnip greens. Flea beetles can jump from plant to plant and quickly infest an entire crop of turnip greens if not controlled. Frequent applications will be necessary to control the rapidly colonizing beetle. Organic products shown to be effective include rotenone, neem products and capsaicin. Capsaicin, derived from hot peppers, gives some control (45% in one study, according to Cornell University).

Cultural Control

• Several cultural control methods can be added to an organic insecticide regiment. These methods include purchasing resistant plants and the preservation, encouragment or introduction of natural enemies. For example, cabbage aphids are the primary host to a very small, black wasp, Diaeretiella rapae, that lays its eggs inside of the aphid. The larva hatch and feed on the aphid. Each pest insect has its own specific cultural control method that will work best on it.