Cabbage Aphid Control

Host Plants

• The cabbage aphid is an exclusive pest of cole crops throughout the world. The pest only infests and feeds on cabbage and other vegetables from the Cruciferae group. Serious infestations are however not common and only occur periodically. The pests do not occur singly but are found in heavy colonies in the infested plants. Though the insects do not feed on non-cole crops, they use these plants as overwintering habitats.

Description

• Adult aphids are 1/16-inch long and greenish white in color. The winged or wingless pests are covered with a gray color wax. The winged cabbage aphids with grayish green wings and black bodies do not have the waxy coating. The pests lay their small eggs, less than 1 mm long, in crop residues. The pear shaped, emerging nymphs or the young are greenish white in color and gradually develop the waxy coating as they mature.

Damage

• Like other aphid species, cabbage aphids are sap sucking pests that feed on plant juices. The insects particularly target the younger foliage and flowering parts and are frequently found buried deep within cabbage heads and Brussels sprouts. Plants in the seedling stage are generally not affected. The insects start to increase in number after transplanting or thinning. Severe infestation leads to curled leaves and the stunted growth or death of younger plants.

Control

• Introducing natural predators in the infested plants helps to reduce or eliminate the need for pesticides. The University of California Extension recommends delaying the use of pesticides as much as possible as long as quality of yield is not affected. Natural predators for control include syrphid fly larvae, lady beetles and the parasitic wasp, Diaeretiella rapae. It important to protect the natural habitat of these predators around plants in order to encourage an increase in population effective for cabbage aphid control. Chemical control options include the use of products containing flonicamid, chlorpyrifos, diazinon or acetamiprid.