Health diagnosis of cassava genetic resources

Contributors to this page: CIAT, Colombia (Daniel Debouck, Roosevelt Escobar, Graciela Mafla); IITA, Nigeria (Dominique Dumet); Bioversity International/ILRI, Ethiopia (Alexandra Jorge); independent consultant (Clair Hershey).

List of pests and diseases of quarantine importance for cassava

Cassava mosaic disease, one of the crop’s most severe constraints in Africa (photo: H. Ceballos)

Click here for additional information on the safe transfer of germplasm of clonal crops.

The list below mentions some of the pests/diseases that are considered important worldwide, but many of them may or may not have relevance in specific countries. It also does not consider pests/diseases of limited relevance (e.g. only important in very few countries). A further disease list can be found here.

The Americas have the greatest diversity of cassava pests, followed by Africa and then Asia. Damage in Africa is often high due to the lack of natural predators of pests.

Recommended methods to detect the presence of each pest or disease



Blotter test, agar test, washing test, direct visual inspection.


Seedling symptom test, dilution plating test.

Weeds, insects and nematodes

Mite-resistant and susceptible selections from the genebank, CIAT (photo: C. Hershey)

Direct visual inspection.

Testing intervals/seasons

Testing before material goes into the genebank or to the field is important to reduce transfer of diseases or pests.


Test seedlings before transfer to the field for regeneration or during regeneration and rogue infected material.


Test plant propagules on entry to genebank and regularly thereafter. Rogue infected material.


Test plant propagules on entry to genebank and regularly thereafter. Rogue infected material.

Weeds, insects and nematodes

Test plant propagules on entry to genebank and regularly thereafter. Rogue infected material.

Recording information during health diagnosis

The following information should be recorded for each health diagnosis step:

References and further reading

Frison EA, Feliu E, editors. 1991. FAO/IBPGR Technical Guidelines for the Safe Movement of Cassava Germplasm. Food and Agriculture Organization of the United Nations, Rome/International Board for Plant Genetic Resources, Rome.

Nolt B, Velasco AC, Pineda B. 1991. Improved purification procedure and some serological and physical properties of Cassava Common Mosaic Virus from South America. Ann. Appl. Biol. 118:105-113.

Nolt B, Pineda B, Velasco AC. 1992. Surveys of cassava plantations in Colombia for virus and virus-like diseases. Plant Pathology 41: 348-354.

Velasco AC, Nolt B, Pineda B. 1990. Comparación de tres métodos de la técnica inmunoenzimática “Elisa” para el diagnóstico de virus del mosaico común de la yuca. Fitopatología Colombiana 14(1):3-9.

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The Genebanks

The 11 CGIAR genebanks currently conserve 730,000 of cereals and grain legumes, forage crops, tree species, root and tuber crops, bananas and crop wild relatives.