Abstract:
Sweet potato is a food security crop for smallholder farmers in Eastern Africa.
Pest and disease constraints are the most important biotic stresses, with viral
diseases being the most devastating. Through a focus-group discussion, it
was established that lack of clean sweet potato planting vines is a major
constraint in production. Consequently, most farmers establish a new crop
from virus-infected volunteer plants or an old sweet potato crop. The
objectives of the study were to identify farmer-friendly technologies for
conservation and maintenance of healthy planting vines; disseminate the best
appropriate technology for farmers and varieties tolerant to sweet potato virus
diseases (SPVD); and expose farmers to sound sweet potato production and
value-addition practices for increased income generation. The experiments
evaluated spraying with dimethoate, physical barriers to virus vectors (insect-proof net and polythene), maize plants as a physical barrier surrounding plots,
and roguing. Parameters monitored were SPVD incidence, whitefly and aphid
populations. High numbers of whiteflies were recorded on the control and
none on the plots protected by net or polythene barriers. Disease control
through roguing was effective, and netting and polythene covers can be of
value for rapid multiplication and maintenance of sweet potato planting
materials. Through a participatory approach, the roguing, net and polythene-cover technologies were demonstrated to farmers in coastal Kenya alongside
farm trials to evaluate 17 sweet potato genotypes for resistance and/or
tolerance to the SPVD. By end of the project, more than 100 farmers had
adopted roguing on their farms. Disease-tolerant varieties were also
disseminated to the farmers after the end of the evaluation period. The on-farm evaluation trials formed a basis for training farmers. Some farmers from
the two key groups had an opportunity to attend a farmer-exchange visit in
Uganda by courtesy of the Regional Universities Forum for Capacity Building
in Agriculture. Integration of farmers in research, coupled with capacity-building, can enhance the adoption of new technologies, thereby enhancing
sustainability.
