Analysis of biological control of cassava pests in Africa. III. Cassava green mite Mononychellus tanajoa

Examined the interactions of Mononychellus tanajoa and Manihot esculenta under West African weather and soil conditions. Field studies had demonstrated the effects of plant and leaf age and rainfall-induced mortality on M. tanajoa population growth. In the absence of effective natural enemies, a model explains, in order of importance, the effects of rainfall, drought stress via the host-plant, food availability (production and persistence of new foliage) and leaf quality (N concentration) on M. tanajoa population growth. Rainfall-induced mortality greatly reduced M. tanajoa populations in the rainy season, drought and N stresses acting indirectly via food availability being most important in the dry season. The combined effects of M. tanajoa feeding and water and N stress on cassava tuber yield were assessed. (See also 89L/09855 & 10026). -from Authors