Comparison of severity of Phytophthora colocasiae (taro leaf blight) disease on in-vivo and in-vitro Pacific-Caribbean and Kenyan taro (Colocasiae esculenta) grown in Kakamega county (Kenya)

Abstract

Taro (Colocasiae esculenta) is an important tuber crop of Kakamega - Kenya. It is nutritionally very rich. Taro leaf blight (TLB) is the most devastating pathogen for its production worldwide and current management strategies are not effective in its control. Studies on TLB disease severity has been done worldwide. However, determining and comparing the disease severity between regions of the world has not been adequately done. Before this study, TLB disease severity on Pacific and Kenyan taro grown in-vivo in Kakamega - Kenya was unknown. Furthermore, knowledge on the differential effect of weather on taro accessions obtained from different regions of the world was scanty. TLB disease severity was assessed on Pacific-Caribbean taro accessions obtained through tissue culture from Pacific- Caribbean. Kenyan taro was obtained from various counties in Kenya. The research aimed at examining and comparing TLB disease severity on Pacific and Kenyan taro. The study was conducted at MMUST University of Science and Technology farm and Maseno university laboratory and greenhouse. All experiments were arranged in a CRD and replicated five times. Data obtained were subjected to ANOVA and the means separated with Least Significant Difference. The results showed that mean disease severity among the Pacific and Kenyan taro varied from 33.2% - 53.5% respectively. TLB disease severity in both in-vivo and in-vitro studies presented higher percentage on Kenyan than Pacific- Caribbean taro. The in-vivo severity range for Kenyan and Pacific taro were; 9.8-28.5% and 4.9-14.8% respectively. Likewise, Kenyan taro maintained higher percentage severity in-vitro, ranging from 20-44% whereas Pacific taro ranged from 9.4-30%. Kenyan Siaya accession KNY/SYA/51 recorded the highest disease severity in-vivo. The lowest disease severity in-vivo was obtained from the Pacific taro CE/IND/06. The study suggested that region of origin of taro, varietal difference and weather would influence TLB severity. This study indicated the need for breeding for resistance to taro leaf blight.