Cassava is attacked by about 50 species of mites. Of these, the most important are Mononychellus tanajoa, M. Progresivus, M. Caribbeanae, Tetranychus urticae and T. Cinnabarinus. These arthropods cause three patterns of damage and have been shown to cause a decrease in root and stake yield of up to 87% and 82% respectively. It is expected that as cassava is further commercialised there will be a greater tendency towards monocropping in large fields and towards the more frequent use of broad spectrum pesticides. As a result, mites as well as other pests will probably increase in importance. Future research should be directed towards a mite management system which combines the use of resistant varieties, cultural practices, biological control and occasional use of selective acaricides. Research up to this point on the biological control of cassava mites has been done with the Mononychellus mites. This work primarily reports on the identification and life cycle studies of the important predators. Although the potential losses due to mites have been shown to be high the mite population level which is damaging to cassava yield is not known. This economic damage level should be estimated with respect to mite populations and/or foliar damage. When the mite population rises above this level it will be necessary to correct the situation by mass release of predators or selective killing of the mites. Good resistance exists. Resistance to the Mononychellus mite is due to several separate mechanisms which when combined promise to result in a stable resistance. Although less work has been done on resistance to Tetranychus and other cassava mites, preliminary data and literature from other crops suggest that the development of resistant cassava varieties is a viable strategy. Given the ease of use and safety of this control method it should be encouraged. Suggestions for future work on all aspects of control are discussed. 1983 Taylor and Francis Ltd.
