Divisi
Potato virus
· Viral
Photo: William M. Brown Jr., Bugwood.org · CC BY 3.0
Potato virus is a group of plant viruses of potato — mainly Potato virus Y (PVY) and Potato leafroll virus (PLRV) — carried from plant to plant by aphids (small soft-bodied sap-sucking insects) and passed down inside the seed tubers you save to replant. Because the virus lives inside the tuber, every time you replant your own saved seed the disease builds up and the crop "runs down" — it gets weaker and yields less each season.
William M. Brown Jr., Bugwood.org · CC BY 3.0 
Rasbak · CC BY-SA 3.0
Why it matters
Once a potato plant catches a virus there is no cure and no spray that heals it — the virus lives inside the plant and inside the tubers it makes. A badly infected field can lose up to 80% of its yield, and worse, the sickness hides in the tubers you save for next year, so it comes back stronger every season you replant your own seed. That is why the whole battle is about keeping it out and pulling out sick plants early — you cannot treat your way out of it.
When to act
First plants with mosaic, leaf-roll or severe stunting, or rising aphid activity; rogue and manage vectors early (no cure)
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 potato virus field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to potato 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 potato virus?
The first thing you see is the leaves change colour and shape. Look for a mosaic — a patchy mix of light and dark green blotches on the leaf, like sun and shadow, instead of one even green. Leaves may also look mottled, crinkled or puckered, and you may see small dead brown flecks (this is the PVY virus).
When should I take action against potato virus?
First plants with mosaic, leaf-roll or severe stunting, or rising aphid activity; rogue and manage vectors early (no cure)
How do I control potato virus?
Prevent first — start with clean seed (the strongest tool): plant certified virus-free seed tubers rather than replanting your own saved seed year after year. This is the single biggest thing you can do — the virus travels inside the tuber, so clean seed breaks the chain. Renew your seed stock every season or two instead of always saving your own.
Which crops does potato virus affect?
Among the crops covered here: Irish potato.
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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