A survey of farmers’ perceptions and management strategies of the sweet potato weevil in Homa bay county, Kenya

Abstract

Sweet potato (Ipomoea batatas L.) is one of the most widely grown root crops
worldwide. In Africa, it is grown in small plots by poorer farmers. Production of the
crop is extremely low in Kenya as compared to other African countries due to the
existence of common insect pests. Sweet potato weevil (Cylas spp.) is known as the
biggest pit fall for production and productivity of the crop in the country. This study
sought to determine the opinion of sweet potato farmers concerning sweet potato
resistance to Cylas spp. and determine control strategies employed by sweet potato
farmers in managing the pest. The study also sought to determine the sweet potato
production constraints faced by the farmers in Homa Bay County, Kenya. The study
was conducted using a Participatory Rural Appraisal approach in which 269 farmers in
the County were interviewed on the sweet potato varieties with field resistance to Cylas
spp., the crops’ production constraints (with emphasis on damage by Cylas spp.) and
farmers’ control strategies in regard to the weevil. Data were also collected from the
farmers whose sample size was determined using the table on sample size selection and
standardization equation. Data were analysed using descriptive statistical techniques
that were frequencies, percentages and standard errors. The study established that
majority of the farmers from Rachuonyo (89.7%) and Ndhiwa (91.9%) were not aware
of any variety that had field resistance to Cylas spp. However, 10.5% of the farmers in
Rachuonyo and 8.1% of the farmers in Ndhiwa identified nine varieties which have
shown relative field resistance to root damage by Cylas spp. The varieties that were
identified to be resistant to Cylas spp. by farmers in Rachuonyo were Kalamb Nyerere,
Tombra, Sinia, Odinga, Kemb 10, Wera and Zapallo. However, the varieties that were
identified to be resistant to Cylas spp. by farmers in Ndhiwa were Amina, Mugande
and Ndege Oyiejo. Further, the findings revealed that Cylas spp. was the most
problematic pest by 90.3% and 96.8% of households in Rachuonyo and Ndhiwa,
respectively. Majority (64.5%) of the farmers in Ndhiwa did not use any methods to
manage Cylas spp. However, farmers in Rachuonyo (26.2%) and Ndhiwa (15.3%)
preferred re-ridging during weeding as a management strategy in regard to Cylas spp.
These findings reiterate the importance of the sweet potato weevil in rural sweet potato
farming systems and thus innovative management strategies are necessary.

Key words: Sweet potato, control strategies, Cylas spp., resistance, pest, variety,
constraints