Divisi
Cotton aphid
Aphis gossypii · Insect
Photo: Clemson University - USDA Cooperative Extension Slide Series, , United States · Public domain
Cotton aphid (Aphis gossypii) is a tiny, soft-bodied, sap-sucking insect — barely the size of a pinhead — that gathers in dense clusters on the growing tips and the undersides of young leaves. Cotton is its main target, but it also feeds on okra, cucumber and melon. The females give birth to live young without mating, so a handful becomes thousands within days in warm, dry weather. As they suck the sap the young leaves curl, pucker and stunt; the aphids rain down sticky, sugary honeydew that turns leaves shiny and then black with sooty mould, and they can carry plant viruses from plant to plant. Late in the season honeydew dripping onto the open bolls makes 'sticky cotton' that stains the white lint and lowers its grade.
Dr Lewis Wilson, CSIRO · CC BY 3.0 
Kirubar · CC BY-SA 4.0
Why it matters
A heavy aphid attack can cost you almost a third of your crop — up to 30% — and even the plants that pull through give you dirty, honeydew-stained 'sticky' lint that buyers pay less for. They are hard to stop once they take hold: the females breed without mating, so a few aphids become thousands in just a few days, and they hide on the undersides of leaves and inside curled tips where a careless spray never reaches them. Worse, the wrong poison kills the ladybirds and tiny wasps that were eating them for free, and the aphids then flare back in far bigger numbers. Catching them early, while the colonies are small and their natural enemies are still winning, is everything.
When to act
Colonies on the growing points/undersides of leaves with visible curling, or sticky honeydew and early sooty mould on most plants.
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 cotton aphid field guide
- Identify it
- Scout for it
- Control it
12 field-guide sections in the app
The full guide to cotton 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 cotton aphid?
The first thing you notice: the youngest leaves at the growing tips curl and cup downward and pucker, and the plant seems to stall and stop growing. Soon those leaves feel shiny and sticky to the touch — that stickiness is honeydew, the sugary liquid the aphids squirt out as they feed — and a black, sooty coating (called sooty mould, a harmless mould that grows on the sugar) spreads over it, so the leaves look dirty and dusted with black. Ants running up and down the stems are a dead giveaway: they guard the aphids and feed on the honeydew.
When should I take action against cotton aphid?
Colonies on the growing points/undersides of leaves with visible curling, or sticky honeydew and early sooty mould on most plants.
How do I control cotton aphid?
Prevent it — don't grow an aphid nursery: aphids breed fastest on soft, over-fed growth, so go easy on nitrogen fertiliser and never pile on extra 'to push the crop' — that flush of lush green leaf is exactly what they multiply on. Pull out weeds in and around the field, because aphids shelter and breed on them between crops. After harvest, plough in or burn the old cotton stalks and trash so the pest has nothing to carry over on. Where you can, choose a tolerant variety and plant early, together with your neighbours, so the crop is past its most tender stage before aphid numbers peak.
Which crops does cotton aphid affect?
Among the crops covered here: Cotton, Cucumber, Okra.
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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