Progrès dans la science et la technologie des cultures

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Survey of Taro Leaf Blight and Identification of the Causative Agent in Southern Ethiopia Region

Zerhun Tomas, Elfinesh Shikur and Alemar Said

In Southern Ethiopia, taro is grown extensively and used to fill seasonal food gaps when other crops are not in the field. However, this important crop has been severely affected by leaf blight disease. Therefore, the current study was designed with the objectives of assessing the intensity of the disease in Southern Ethiopia and to identify the causative agent of taro leaf blight. For this purpose, total of 27 farm fields were surveyed across 9 Woredas of two zones, Wolaita and Kembata Tembaro Zone, during 2017 cropping season. Among fields surveyed 15 representative taro leaf bight samples were collected for the identification of the causative agent. All the 15 isolates had fluffy or slightly fluffy colony texture and whitish or dull white colony color. Mycelium was aseptate and Sporangia types were ranged from semipapillate to papillate, Sporangia shape were ovoid or lemon shaped. Based on colony character and sporangial nature the pathogen isolated was identified as Phytophthora colocasiae. The mean P. colocasiae leaf blight incidence varied from 10 to 100% while mean disease severity ranged from 16.67 to 50%. This indicates the disease occurred in moderate to severe form in all taro surveyed fields. The present study revealed the importance of Phytophthora leaf blight of taro in Southern Ethiopia. Future research should be directed towards surveying more agro ecologies and to know effect of the disease on taro production in Ethiopia.