Cabbage aphid
Caused by: Brevicoryne brassicaeaProblem Category: Insect
Symptoms: Large populations can cause stunted growth or even plant death; Insect may be visible on the plant leaves and are small, grey-green in color and soft bodied and are covered with a white waxy coating; prefer to feed deep down in cabbage head and may be obscured by the leaves.
Comments: Cabbage aphids feed only on cruciferous plants but may survive on related weed species.
Management: If aphid population is limited to just a few leaves or shoots then the infestation can be pruned out to provide control; check transplants for aphids before planting; use tolerant varieties if available; reflective mulches such as silver colored plastic can deter aphids from feeding on plants; sturdy plants can be sprayed with a strong jet of water to knock aphids from leaves; insecticides are generally only required to treat aphids if the infestation is very high - plants generally tolerate low and medium level infestation; insecticidal soaps or oils such as neem or canola oil are usually the best method of control; always check the labels of the products for specific usage guidelines prior to use.
Control: Yellow sticky traps 20-40 per acre