Abstract:
Rice is one of the most important cereal crops in Kenya coming third after maize and
wheat. It forms a very important diet for majority of Kenyans and is the source of livelihood in
the Mwea region, Kenya. The demand for rice in Kenya has increased dramatically over the
last few years while production has remained low. This is because rice production has been
faced with serious constraints notably plant disease of which the most devastating is rice blast.
Rice blast is caused by Magnarpothe oryzae fungus and is the one of the most frequently and
costly rice disease in the Mid-South and temperate rice growing regions. The aim of this study
was to determine the economic impact of rice blast on yield of susceptible varieties, estimate
the yield losses caused by rice blast on susceptible varieties in Mwea, and estimate the
increased cost of production due to the rice blast disease. The study involved a survey in which
a sample population of 50 farmers from a targeted population of 500 within Mutithi in Mwea
region were interviewed. The collected data was analyzed using SPSS software. Descriptive
statistics were used to summarize the socio-demographic characteristics and farmers perception
on rice blast disease. It was found that farmers in Mwea continue to count on average 14%
yield loss every season due to blast occurrence. The degree of yield losses depended on the rate
of blast infection; in 2014 the disease was most prevalent at 62% whereas the average yield
loss being 39% per acre. The rice cultivar Basmati 370 was ranked as the most susceptible to
blast in spite being ranked the most grown variety in Mwea; this is because of its high demand
and market price. Farmers spent on average US $9.00 to mitigate the disease. However, it was
noted that farmers could not realize the impact of rice blast on cost of production as the
increased cost was covered by the premium prices of the rice. Our findings suggest that any
reduction in blast via breeding will have significant positive impacts in reducing food insecurity
in Kenya through increased supply of rice, as well as decreased price due to high productivity
at a lower cost.
