Divisi
Diplodia root and stalk rot
Stenocarpella maydis · Fungal
Photo: Jrodrigomendoza · CC BY-SA 4.0
Diplodia root and stalk rot is a fungus (Stenocarpella maydis, once called Diplodia) that lives on old maize stalks and cobs left on the ground and infects the roots, crown and lower stalk of the next maize crop — especially plants that were stressed after flowering. It rots the base from the inside, cutting off water and food, so plants die early, soften and fall over, and cobs fill poorly. The same fungus also causes a white, cottony cob rot.
Why it matters
Diplodia rots your maize from the roots and the base of the stalk upward, so plants die early and topple before the cobs are full — a bad attack can cost you up to 40% of your harvest, and the fallen, mouldy cobs that reach the ground rot and are lost completely. Once the fungus is inside the stalk, no spray can reach it and the plant will not recover — this is a disease you beat before planting, not one you cure in the field. Because it survives on old maize trash and attacks stressed plants, growing maize after maize on the same land, year after year, feeds it and makes each season worse.
When to act
Manage preventively through rotation and residue burial; scout from flowering for early lodging and stalk softening.
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 diplodia root and stalk rot field guide
- Identify it
- Scout for it
- Control it
15 field-guide sections in the app
The full guide to diplodia root and stalk rot — 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 diplodia root and stalk rot?
The first thing you see: whole plants wilt and die too early, weeks before the rest of the field is ready. The leaves fade to a dull grey-green, then to a bleached, straw colour — the plant looks 'frosted' or scorched from the ground up while nearby healthy plants are still green.
When should I take action against diplodia root and stalk rot?
Manage preventively through rotation and residue burial; scout from flowering for early lodging and stalk softening.
How do I control diplodia root and stalk rot?
Prevent — rotate out of maize (your strongest tool). The fungus can only live on old maize; it starves without it. Do not plant maize after maize on the same land — grow a non-host crop such as beans, groundnut, soya or sunflower for a season so last year's fungus dies off before maize returns.
Which crops does diplodia root and stalk rot affect?
Among the crops covered here: Maize.
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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