is a hugely important crop in central West Africa. Unfortunately, it is
affected by some major diseases and pests. Cassava Mosaic Virus has spread to
many parts of Africa and can reduce yields considerably. In the field, you
can recognise the virus by its mosaic pattern on the leaves, as well as
making the leaf deformed and with blisters. The roots are reduced in size as
well. This virus is transmitted from one plant to another through the
whitefly insect that feeds off the sap of the cassava. This small white fly
is about the size of the tip of a ball point pen., and is generally found on
the underside of the leaf. They are more active early in the morning and
disease resembles another virus, called Cassava Brown Streak Virus, which
also causes mosaic colours on the leaves. However, they differ in two ways:
the tubers have dry brown streak inside, and the leaves are not deformed.
disease is caused by a virus that lives in the plant and that cannot be seen,
apart from its symptoms. It is not possible to cure a plant once it has been
infected materials from the field is a cultural technique that aims to reduce
the amount of disease in the field, and to control the spread to other health
plants. It may also reduce the chances of the disease being in the field the
following season. Seeds from an infected plant will also be diseases, as well
as seedlings or cuttings.
choose healthy seeds, cuttings or seedlings, without any disease symptoms or
white flies on them, from a respected or well run nursery. This will reduce
the chances of getting the disease in your field in the first place. Certified
multiplication nurseries, controlled by the SENASEM are the best choices.
the field once a week to check on the state of the seedlings or plants. If
many whiteflies are observed, there is a high chance the disease might
spread. Get ready to pull out diseased plants at the first symptoms. Put them
in a plastic bag when you uproot them (to keep the whiteflies in) and
destroy them by burning them outside the field. In addition:
weeds that could be alternative hosts of
- Intercrop with maize or cowpeas, to
planting cassava if your neighbours have virus-infected cassava as the virus will be carried by
whiteflies to your field.
- Avoid planting alternative
hosts for the whitefly which is the vector for this virus. Crops such as tomato
should not be planted in or nearby cassava field.