Divisi
Cabbage aphid
Brevicoryne brassicae · Insect
Photo: Sanjay Acharya · CC BY-SA 4.0
The cabbage aphid (Brevicoryne brassicae) is a small, soft-bodied, grey-green insect dusted with a fine white-grey mealy wax, so a colony looks like ash or flour on the plant. It attacks only the cabbage family — cabbage, kale, rape, broccoli and cauliflower — packing into dense colonies on the growing point (the heart) and the undersides of the youngest leaves. In cool, dry weather the females give birth to live young without mating, so colonies explode in days. As they suck sap they stunt and curl the leaves, coat the plant in sticky honeydew that turns black with sooty mould, and can pass on several brassica viruses.
Rasbak · CC BY-SA 3.0 
James K. Lindsey · CC BY-SA 3.0
Why it matters
Cabbage aphids can take up to 40% of your brassica crop — nearly half. They don't only weaken the plant by sucking its sap; they pack into the heart and foul it with sticky honeydew, black sooty mould and grey cast skins, so even lightly infested cabbages, kale or rape won't sell. Once a colony is set it is hard to stop: in cool, dry weather a few aphids become thousands within a week — each female births live young without mating — and they hide deep in the growing point and under the leaves where sprays struggle to reach. Catching them early, while colonies are few and near the surface, is everything.
When to act
colonies on the growing point or 5-10% of plants infested
This guidance is general, compiled from published agronomic references including FAO and CABI. Thresholds and timing shift with your crop, your variety and the season.
In much of the region a spray is simply called mushonga — medicine. But a chemical group you cannot name is one you cannot rotate, and a product you did not write down has no pre-harvest interval you can observe. Mushonga, and other farming words →
The full cabbage aphid field guide
- Identify it
- Scout for it
- Control it
12 field-guide sections in the app
The full guide to cabbage aphid — every symptom to check, how and when to walk your field looking for it, and the controls that actually work, ranked. Built into your crop plan, so you are told to look before it costs you a harvest.
Crops it affects
Frequently asked questions
How do I identify cabbage aphid?
The damage first: the youngest inner leaves and the heart of the plant curl, pucker and yellow, and growth stalls. Look for a shiny, sticky coating (honeydew — the sugary waste the aphids drip) on the leaves that later turns into a black, dusty film (sooty mould), and heads, hearts or curds fouled with insects and white flecks that no buyer will take.
When should I take action against cabbage aphid?
colonies on the growing point or 5-10% of plants infested
How do I control cabbage aphid?
Prevent it — break the bridge: as soon as a crop is finished, pull out and destroy (feed to livestock, bury or burn) all old brassica stalks, residues and self-sown volunteer brassicas. These are the green bridge the aphids survive on between crops. Don't plant brassicas in the same ground back-to-back — leave a host-free gap and rotate to a non-brassica like maize or beans so the aphids starve.
Which crops does cabbage aphid affect?
Among the crops covered here: Cabbage, Rape / covo / kale, Spider plant.
Catch it before it costs you a harvest
Divisi builds scouting into your crop plan — it tells you when to walk your field, what to look for at that stage, and what to do when you find it. Free for farmers, works offline.
Check what grows on your farm