Cassava mosaic disease
A patchy yellow-green mottle and stunted growth that travels inside the planting material itself, not just through its whitefly vector — the single biggest reason to be strict about where cuttings come from.
- Pathogen
- Cassava mosaic geminiviruses
- Spreads by
- Whitefly, and critically, infected stem cuttings
- Favoured by
- Whitefly activity; use of diseased planting material
- Main risk
- Mottled, stunted plants with sharply reduced tuber yield
Overview
Cassava mosaic disease (CMD) is caused by a group of related geminiviruses and is the single most damaging disease of cassava (tapioca) wherever the crop is grown. Infected plants show a characteristic patchy yellow-and-green mottle on the leaves, often with distortion, puckering and reduced leaf size, and badly affected plants are visibly stunted with a smaller, poorer root system and cut tuber yield.
The virus is spread by the whitefly Bemisia tabaci, but the far more important route in practice is through infected stem cuttings themselves — because cassava is propagated entirely from cuttings taken from an older plant, a diseased mother plant passes the virus directly into every cutting taken from it. A single batch of infected planting material can seed an entire new field with the disease before a single whitefly ever visits it, which is why source discipline matters more than spraying for this disease.
How to identify it
- A patchy yellow-and-green mottle on the leaves, giving a mosaic pattern.
- Leaf distortion, puckering and reduced leaf size on badly affected plants.
- Visible stunting compared with healthy neighbouring plants.
- A smaller, poorer root system and reduced tuber size and yield at harvest.
What causes it and when
- A group of related geminiviruses, spread by the whitefly Bemisia tabaci.
- Critically, also carried inside infected stem cuttings themselves — the virus travels with the planting material, not just the insect vector.
- A single diseased mother plant can pass the virus to every cutting taken from it.
- Whitefly activity, and the presence of infected plants nearby, both increase field-to-field spread.
Cultural & organic control
- Take stem cuttings only from healthy, vigorously growing, visibly symptom-free mother plants — this is the single most effective control available.
- Maintain a dedicated, clean nursery block of mother plants for future cuttings rather than cutting from any convenient plant in a mixed field.
- Rogue out and destroy infected plants promptly so they are never used as a source of cuttings.
- Manage whitefly on young plants to slow field-to-field spread, though this alone will not stop the disease if infected cuttings are still being planted.
Chemical (vector) control
- There is no cure for an infected plant — no spray removes the virus once a plant carries it.
- A recommended insecticide can reduce whitefly numbers on young plants where pressure is high, slowing but not stopping spread.
- Vector control is a secondary measure; clean planting material is what actually prevents the disease.
- Confirm the current recommended approach for whitefly management with your local KVK.
Prevent it coming back
- Base every new planting on cuttings from a clean, dedicated mother-plant nursery, checked regularly for symptoms.
- Never take cuttings from a plant showing mosaic symptoms, even if the rest of the field looks fine.
- Rogue infected plants promptly and manage whitefly on young plants as a supporting measure.
Crops most at risk
Where this problem is called out in our crop guides — open a crop for the full package of practices.
Frequently asked questions
My tapioca leaves have a yellow-green mottled pattern. What is it?
That mottling is almost certainly cassava mosaic disease. It is spread by whitefly and, critically, also carried inside infected stem cuttings — so a diseased mother plant passes the virus directly into every cutting taken from it. There is no cure once a plant is infected; remove and destroy it, and never take cuttings from it.
Can spraying cure a mosaic-infected tapioca plant?
No — there is no spray that removes the virus from an infected plant. Insecticide is only useful to reduce the whitefly vector on young, still-healthy plants nearby, which slows further spread but does not cure anything already infected. The real prevention is always taking cuttings from healthy, symptom-free mother plants.
Why does one diseased mother plant matter so much?
Because cassava is propagated entirely from cuttings taken from an older plant, not from seed — a single diseased mother plant can pass the virus into dozens of cuttings taken from it, seeding an entire new field with the disease before a single whitefly ever visits it. That is why source discipline for planting material matters more here than for most other crop diseases.
Symptoms and control measures follow ICAR, KVK and state agricultural-university package-of-practices; any named chemical is a registered use. Always read the product label and confirm the dose for your crop and zone. editorial policy.