Abstract:
Calotropis procera has a great potential for domestication and commercialization in Kenya for fibre production.
However, the shrub experiences dieback condition caused by unidentified fungi. This makes it difficult to
prevent dieback during cultivation, a situation that may lead to low productivity and financial losses. This
study determined dieback prevalence, severity and causative agents among naturally growing Calotropis procera
in the semi-arid regions of Kenya. A repeated measure research design was used. Purposive sampling
technique was used in selecting Tharaka and Makueni as study sites. Simple and systematic random sampling
techniques were used in developing main and sub plots, respectively. Simple random sampling technique was
used in selecting 16 cuttings from each block for laboratory analysis. In the laboratory, specimens were
obtained from samples, sterilized, rinsed, blotted and incubated at 23°C followed by observation of spores
under a Microscope. Mixed analysis of variance (ANOVA) and 2*4*6 factorial ANOVA using SPSS version
25 was used in analysis. There were significant differences in dieback prevalence and severity at different time
points with the highest prevalence (78.56%) and severity index (3.54) reported in (September-November)
2019. Fusarium was the dominant dieback causative fungi with dominance ranging from 32.29% to 43.38%.
In conclusion, the study established that naturally growing Calotropis procera stands in semi-arid regions of
Kenya experience dieback throughout the year though at varying levels.
