Divisi
Aphids
Aphididae · Insect
Photo: Sanjay Acharya · CC BY-SA 4.0
Aphids are tiny, soft, pear-shaped sap-sucking insects — green, black, grey or waxy-white, each no bigger than a pinhead — that gather in dense clusters on the tender growing tips, flower buds and leaf undersides of many crops, from beans, cowpea and cabbage to tomato, pepper, potato, cotton, citrus and wheat. They multiply explosively in warm, dry weather, curling and stunting new growth, coating leaves in sticky honeydew that blackens with sooty mould, and — most damaging of all — carrying plant viruses from field to field.
André Karwath aka Aka · CC BY-SA 2.5 
Alvesgaspar · CC BY-SA 3.0
Why it matters
Aphids are tiny sap-suckers that can quietly cost you up to half your crop (50%). They drain the tender growing tips so leaves curl and plants stunt, they coat everything in sticky honeydew that turns black with sooty mould and dirties your produce, and worst of all many of them carry plant viruses — a disease no spray can cure. They are hard to stop once they settle, because a few aphids become thousands in a few days (the females give birth to live young without even mating) and they hide under curled leaves and leaf undersides where sprays miss them — so the whole game is catching them early, while the colonies are still small.
When to act
Act when colonies build on growing tips of many plants, when honeydew and curling appear, or on virus-sensitive crops even at low numbers.
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 aphids field guide
- Identify it
- Scout for it
- Control it
14 field-guide sections in the app
The full guide to aphids — 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 aphids?
The first thing you see is the damage, not the insect: the newest leaves and growing tips curl, pucker and twist, growth turns stunted and yellowish, and leaves get a shiny, sticky coating (honeydew) that soon turns black and sooty — a mould that grows on the sugar. Ants running up and down the stems are a giveaway: they farm the aphids for that honeydew and guard them.
When should I take action against aphids?
Act when colonies build on growing tips of many plants, when honeydew and curling appear, or on virus-sensitive crops even at low numbers.
How do I control aphids?
Prevent it — don't grow the soft, sappy shoots aphids love: feed balanced nutrients and go easy on nitrogen (too much — like heavy urea — flushes out tender growth that aphids breed on fastest). Clear the weeds in and around the field, because they shelter aphids and viruses between crops. Keep a new planting away from old, infested or virus-sick crops.
Which crops does aphids affect?
Among the crops covered here: Cabbage, Common bean, Cotton, Cowpea, Tomato, Wheat.
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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