---

Cabbage Aphid

Description:

Adult and nymph: Gray-green to powdery blue. Soft-bodied, covered with a fine whitish wax. Aphids cluster on the underside of leaves.

Common host plant(s):

Cabbage, cauliflower, kohlrabi, collards, brussels sprouts, broccoli and kale.

Damage:

Curled and distorted leaves, stunted plants. Aphids may severely damage plants; seedlings may be killed.

Distribution:

Throughout United States, particularly troublesome in the south.

Lifecycle:

Winged female aphids infest fields, giving birth to live, mostly female nymphs at the rate of about 25 per week over a 2 to 3 week period. Nymphs reach maturity in 7 to 14 days and begin the cycle again. Numerous generations are produced in this manner over a season. Cabbage aphids overwinter as eggs in crop residue.

Thresholds:

Rating	Number of Aphids on Plant
0 (none)	0
1 (trace)	1-3
2 (low)	4-10
3 (low/moderate)	11-30
4 (moderate/high)	31-100
5 (high)	101 to 300
6 (very high)	301 or more

Check plants, not neglecting the undersides of leaves, and rate plantings according to the table above.

• For seedlings: If the rating is 1 or more, an insecticide shouldbe profitable.
• For established plantings: i) an insecticide is warranted if the average rating is 2 or more, ii) if the rating is less than 2, but any individual plant is rated as 4 or more, scout field again in three days, iii) the above recommendations for insecticide use can be ignored if heavy rains are forecast or if many natural aphid predators are present in the plantings

Cultural Control:

Localized aphid infestations can be hand-picked or pruned out. Before planting vegetables, check surrounding weeds and other plants for aphids and destroy where found. Remove any aphids discovered on transplants before planting. Always remove all crop residues immediatly after harvest.

Organic/Biological Control:

Spray foliage with insecticidal soap. Many natural enemies, including parasitic wasps and lady beetle larvae, help keep aphid populations in check.

Chemical Control:

Treat with a registered insecticide when insects appear in damaging numbers.

Notice: Because pesticide labels can change rapidly, you should read the label directions carefully before buying and using any pesticides. Regardless of the information provided here, you should always follow the latest product label when using any pesticide. If you have any doubt, please contact your local Extension agent or pesticide dealer for the latest information on pesticide label changes.

Disclaimer:  Commercial products named on this site are for informational purposes only. Virginia Cooperative Extension does not endorse these products and does not intend discrimination against other products which also may be suitable.

References:

Foster, Rick and Brian Flood. 1995. Vegetable Insect Management, Meister Publishing Company, Willoughby, Ohio. p. 116.

Prepared by Alexandra Spring and Eric Day (Modified from a publication by the USDA)