Coffee Thread Blight (Corticium koleroga): a Coming Threat for Ethiopian Coffee Production

Kifle Belachew

doi:10.4172/2157-7471.1000303

Abstract

Besides its importance coffee production constraints with number biotic factors of which diseases are major. Coffee is prone to a number of diseases that attack fruits, leaves, stems and roots, and reduce yield and marketability. Major coffee diseases in Ethiopia are Coffee berry diseases (Colletotrichum kahawae), Coffee wilt disease (Gibberella xylarioides) and coffee leaf rust (Himalia vestatrix) however, the rest diseases considered minor. Thread blight of coffee caused by Corticium koleroga is an important disease of Coffee in India. Thread blight diseases in Ethiopian coffee for first time recorded at Gera and Metu agricultural research sub-stations in 1978. However it sporadically occurs between June and September, but becoming important at high land coffee growing areas of southwestern, Ethiopia. Investigations including diagnostic surveys for assessing the disease occurrence, prevalence, incidence and severity was conducted and the sample was brought to Plant Pathology Laboratory of Jimma Agricultural Research Center. The results of study showed that the disease syndrome on detached coffee plants were similar with thread blight of coffee recorded so far and observed at the field. The disease invariably attacks coffee leaves, branches, twigs and berries with characteristic blight symptoms. White fungal threads were seen on the young stems and succulents tender tissues of coffee trees. These threads eventually become dark brown in color grow and spread to cover underside of leaves while coffee berries on infected braches are also completely destroyed leading to total crop failure. The isolation and identification of the causal pathogen from samples of leaves, berries, branches and shoots consistently produced fungal species which may be Corticium koleroga that further proved by pathogenicity tests. The disease mean incidence and severity during first outbreak (2008) at Limmu coffee plantation farm of “Gummer” was 49.02 and 9.8%, respectively. The second reported outbreak of the diseases was from Bebeka coffee estate of “Disadis” farm (2012). Current area wide outbreak at major coffee growing areas of southwest, west and south Ethiopia was in 2014 with mean incidence and severity of 58.44 and 32.59%, respectively, resulting in considerable damages. Among others, climatic factors prolonged rainfall with long period of wet favored the thread blight disease outbreaks implicating the present climate change scenarios are favoring challenging diseases on Arabica coffee production in Ethiopia.

Highlights

Coffee is one of the highly preferred international beverages, and one of the most important trade commodities in the world next to petroleum [1]
While major coffee diseases are Coffee Berry Diseases (CBD) caused by Colletotrichum kahawae, Coffee Wilt Disease (CWD) of Gibberella xylarioides and coffee leaf rust caused by Hemileia vastatrix, the rest of diseases considered to be minor [5,6]
Such symptoms are similar to that of the disease known as thread blight caused by Corticium koleroga documented so far [5,12,13,14] officially reported on Arabica coffee as minor and locally important coffee diseases in Ethiopia (Figure 1)

Summary

Introduction

Coffee is one of the highly preferred international beverages, and one of the most important trade commodities in the world next to petroleum [1] It is currently grown over eighty countries in the tropical regions with an estimated 125 million people in Latin America, Africa and Asia depend on it for their livelihoods [2,3]. High rainfall and relative humidity are common in major coffee growing areas, which favors disease development and survival of inoculums on crop or alternate hosts over seasons. These conditions generally result in disease epidemics that reduce coffee yield. While major coffee diseases are Coffee Berry Diseases (CBD) caused by Colletotrichum kahawae, Coffee Wilt Disease (CWD) of Gibberella xylarioides and coffee leaf rust caused by Hemileia vastatrix, the rest of diseases considered to be minor [5,6]

Methods

Results

Conclusion