Divisi
Clubroot
Plasmodiophora brassicae · Fungal
Photo: Rasbak · CC BY-SA 3.0
Clubroot is a stubborn soil disease of the cabbage family — cabbage, cauliflower, broccoli, kale, rape, canola, turnip and radish. It is caused by a tiny soil-borne germ (Plasmodiophora brassicae) that attacks the roots and swells them into useless clubs and knobs, choking off the plant's water and food. It thrives in wet, sour (acidic) soil in warm weather (about 18–25°C), and travels from field to field in contaminated soil clinging to tools, boots, wheels, running water and infected seedlings. Once it settles in a field its spores can wait in the ground for 15–20 years, so it cannot be sprayed away — it has to be kept out and managed.
Leafhopper65 · Public domain 
Rasbak · CC BY-SA 3.0
Why it matters
Clubroot swells the roots of your cabbage-family crops into useless lumps, so the plant can no longer drink water or take up food from the soil — it wilts, stays small, and gives you little or no head. A bad attack can cost you up to 80% of the crop — four out of every five plants. The worst part is that once it is in your soil it stays there: the tiny spores can live in the ground for 15 to 20 years, and no spray will clean them out. That is why keeping it off your land — clean seedlings, clean tools, limed and well-drained soil — matters more than anything you can do once it has arrived.
When to act
A field-status threshold: once clubroot is confirmed in a field, treat it as infested and manage on every future brassica crop; wilting patches plus clubbed roots on lifted plants confirm presence.
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 clubroot field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to clubroot — 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 clubroot?
The first sign is wilting in the heat of the day. On a warm afternoon your cabbages, kale or rape flop and droop as if they are thirsty — then perk up again overnight when it is cool. Day after day they wilt like this even though the soil is still damp — that is the giveaway.
When should I take action against clubroot?
A field-status threshold: once clubroot is confirmed in a field, treat it as infested and manage on every future brassica crop; wilting patches plus clubbed roots on lifted plants confirm presence.
How do I control clubroot?
Sweeten the soil with lime (prevent). Clubroot loves sour (acidic) soil, so spread lime to raise the soil toward neutral — a pH of about 7 — well before you plant. This is your single strongest weapon: the disease struggles badly in limed, non-acid ground.
Which crops does clubroot affect?
Among the crops covered here: Cabbage, Rape / covo / kale.
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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