Cabbage aphid on cabbage, kale and Brussels sprouts
Hoverfly larvae, lady beetles and the parasitoid wasp Diaeretiella rapae are among the cabbage aphid's natural enemies (UMass). In UMass flower trials in 2018 and 2019, alyssum, dill, cilantro and Ammi majus drew the most hoverflies. Alyssum is itself a brassica, though, and attracted flea beetles. UMass warns that natural enemies may not prevent the high numbers that build up in cool autumn weather, so keep checking long-season crops such as Brussels sprouts.
At a glance
- Damage
- Dense grey waxy colonies; curled, yellowed leaves; contaminated heads and sprouts
- Type
- Sap feeding · virus vector
- Settings
- Field, Garden, Under glass
- Threshold
- Commercial: treat at more than 10% of plants with at least one aphid (UMass); 1–2% for cabbage in California (UC IPM)
- Ally
- Syrphidae
- Rate
- Wild — nothing to release. Plant alyssum, dill, cilantro or Ammi majus near the brassicas to draw hoverflies in
How to confirm it
Dense colonies of grey-green aphids coated in a dusty white wax, like cigarette ash, under brassica leaves and in growing points or sprouts. Young nymphs may lack the wax and look green. Bronze aphid mummies among them mean a parasitoid wasp is at work.
Identification, lifecycle, degree days and every control option are on the full Cabbage aphid profile. Not sure it is this pest? Answer four questions about the damage.