植物病理学および微生物学ジャーナル

概要

An Investigation on Fusarium Wilt Disease of Tea Caused by Fusarium oxysporum in Southwest Ethiopia

Nagassa Dechassa1*, Gabissa Gidissa1 and Legesse Hagos

Tea (Camellia sinensis) production is constrained by fusarium wilt disease in Ethiopia. Despite this, there is lack of information on the status of the disease and its associated factors, and lack of knowledge on features of the pathogen associated with the disease as there have been no any systematic assessments conducted so far. Therefore, the current works were designed with the objectives to assess the distribution of the disease and its associated factors, identify the associated pathogen and determine the pathogenicity of the pathogen isolates. For this purpose, field surveys were carried out across three tea estate farms and tea out growers surrounding them in Southwest Ethiopia during the 2019 season. Causative pathogen of the disease was identified using cultural and morphological features. The average fusarium wilt incidence varied from (0 to 20%). The disease intensity was positively and strongly associated with altitude (r=0.83) and positively and intermediately associated with rainfall (r=0.85), but the disease intensity was negatively and strongly associated with maximum temperature (r=-0.84) and negatively and weakly associated with minimum temperature (r=-0.31). The colony growth rate of the isolates was ranging between 8.38 and 9.00 mm/day. F. oxysporum isolates produced mycelia with floral white front and back side color, circular in form, flat in elevation, filiform margins and produced in abundance. The macroconidial shape of all the isolates was slightly curved with curved apical shape, footed basal shape and an average of 3 septa per macro conidia whereas micro conidial shape of all the isolates was fusiform without septation. The present study revealed the economic importance of fusarium wilt disease of tea in Southwest Ethiopia. Future research should be directed towards the investigation and determination of management options for the control of this important disease of tea in the country.