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Cowpea mosaic virus
Cowpea aphid-borne mosaic virus · Viral
Photo: BigB716$ (Wikimedia Commons) · CC0
Cowpea mosaic (cowpea aphid-borne mosaic virus) is a virus that lives inside the cowpea plant itself. It arrives two ways: hidden in infected seed, and carried plant-to-plant by aphids (small soft insects) that feed briefly on a sick plant, then on a healthy one. Once a plant is infected there is no spray that can cure it, so the whole fight is about clean seed, early removal, and keeping the aphid carriers down.
Why it matters
Cowpea mosaic can wipe out up to 70% of your harvest when infected seed and heavy aphid activity come together. It hits hardest early: young plants stay stunted, flower poorly, and set few or empty pods. And here is the hard part — the virus lives inside the whole plant (it is systemic), so there is no medicine or spray that cures a plant once it is sick. Your only wins are stopping it getting in and pulling out the sick plants before they infect the rest.
When to act
First mosaic/mottled seedlings appearing, or high aphid vector activity on a susceptible crop; rogue immediately.
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 mosaic virus field guide
- Identify it
- Scout for it
- Control it
17 field-guide sections in the app
The full guide to cowpea mosaic virus — 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 mosaic virus?
What you see first: on the youngest leaves, a patchy mix of light-green and dark-green blotches — like a light-and-dark quilt — instead of one even green. This mottled pattern is called mosaic.
When should I take action against cowpea mosaic virus?
First mosaic/mottled seedlings appearing, or high aphid vector activity on a susceptible crop; rogue immediately.
How do I control cowpea mosaic virus?
Prevent — start with clean seed (your strongest move): plant certified virus-free or known-clean seed, and never save seed from a field that had mosaic. Most outbreaks start from infected seed, so clean seed is the single most powerful thing you can do.
Which crops does cowpea mosaic virus affect?
Among the crops covered here: Cowpea.
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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