Divisi
Cowpea aphid
Aphis craccivora · Insect
Photo: David Perez · CC BY 3.0
Cowpea aphid (Aphis craccivora) is a small, shiny jet-black aphid — each one no bigger than a pinhead — that packs into dense colonies on the growing tips, soft young stems and flower stalks of cowpea, groundnut and beans. It multiplies explosively in warm, dry weather, sucking the sap and coating plants in sticky honeydew, and — most dangerously — it carries cowpea mosaic and other legume viruses from plant to plant, so even a few aphids can matter. Ants tend and guard the colonies for their honeydew, chasing off the very insects that would otherwise eat the aphids.
Nativeplants garden · CC BY-SA 4.0 
Luis Fernández García · CC BY-SA 4.0
Why it matters
Cowpea aphid can cost you up to a third of your crop — 35% — and it hurts you two ways at once. It sucks sap from your seedlings, stems and flower stalks so plants stay small, twisted, and drop their flowers and young pods; worse, it carries cowpea mosaic virus from plant to plant the way a mosquito carries malaria, and once a plant is infected no spray can cure it. Because the aphids breed extremely fast in warm, dry weather and ants protect them from the insects that would eat them, a few colonies you miss on the first seedlings can flood the whole field within days. That is why catching them early, on the very first seedlings, matters more than anything else you do.
When to act
Dense shiny black aphid colonies on the growing points/stems of seedlings, or aphids present when cowpea mosaic risk is high.
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 cowpea aphid field guide
- Identify it
- Scout for it
- Control it
18 field-guide sections in the app
The full guide to cowpea 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 cowpea aphid?
The damage you see first: the growing tips and flower stalks look stunted, twisted and curled and the young leaves pucker; under a heavy attack the plant sheds its flowers and young pods. Everything feels sticky — that shine is honeydew, the sugary liquid the aphids leave behind — and a black sooty mould (a harmless mould that grows on the sticky honeydew) often spreads over the leaves on top of it.
When should I take action against cowpea aphid?
Dense shiny black aphid colonies on the growing points/stems of seedlings, or aphids present when cowpea mosaic risk is high.
How do I control cowpea aphid?
Prevent — grow a resistant variety: where you can get the seed, plant an aphid-tolerant or resistant cowpea variety. This is your cheapest and longest-lasting defence — it costs nothing extra once the seed is in the ground, and it slows the virus down as well.
Which crops does cowpea aphid affect?
Among the crops covered here: Cowpea, Groundnut.
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.
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