Biocontrol Potential of Microbial Antagonists  against Mango Anthracnose Disease  (Colletotrichum gloeosporioides)

Lamenew, Fenta

dc.contributor.author	Lamenew, Fenta
dc.date.accessioned	2022-09-21T12:22:25Z
dc.date.available	2022-09-21T12:22:25Z
dc.date.issued	2022-08
dc.identifier.uri	http://ir.bdu.edu.et/handle/123456789/14239
dc.description.abstract	Mango anthracnose caused by Colletotrichum gloeosporioides is among the most important diseases of fruits in subtropical and tropical regions of the world. Currently, the control of fruit and vegetable diseases relies mainly on the use of synthetic fungicides. However, due to peoples‘ concern on the side effects of synthetic fungicides, looking for non-chemical control methods to reduce postharvest decay is becoming crucial. The aim of this study was therefore, to isolate and characterize Colletotrichum spp., screening and evaluation of potential microbial antagonists against Colletotrichum gloeosporioides; and those potential antagonistic isolates viz Lactobacillus and yeast isolates were evaluated tolerant for reidomil and mancozab fungicide. Isolationof Colletotrichum spp. was done from symptomatic anthracnose infected mango fruits and a total of 72 isolates were screened from the host. Based on phenotypic characteristics, the isolates were divided in to six distinct morphotypes. Based on morphological, physiological and cultural characteristics, four were found to be C. gloeosporioides, while the remaining two were found to be C. acutatum. Secondly, potential antagonistic microbes were isolated and characterized from healthy looking mango fruits against C. gloeosporioides. A total of 66 yeast isolates and 48 Lactobacillus isolates were screened out of which 16 yeasts and seven Lactobacillus isolates were found to be effective in inhibiting the growth of C. gloeosporioides pathogen on dual culture and over lay dual culture methods respectively. Based on microscopic and macroscopic characterizations and other morphological, cultural, biochemical and physiological tests, the yeasts were characterized to be Candida, Cryptococcus, Saccharomyces, and Rhodotorula and the Lactobacillus isolates were characterized to be Lactobacillus acidophilus. In vitro and in vivo results of this study revealed that the antagonists (yeast and Lactobacillus) inhibited mycelial growth of the pathogen (C. gloeosporioides) as compared to the control in the dual culture assay. The mechanism of the antagonists to inhibit the growth of the pathogen revealed that antagonistic Lactobacillus and yeast isolates were able to produce antifungal compounds. In vivo experiments of these antagonists were also tested against the pathogen (C. gloeosporioides) and the results of this study indicated that both Lactobacillus and yeast antagonist isolates were able to inhibit the pathogen. The third objective of this study was to evaluate the fungicide tolerance of potential antagonistic isolates viz Lactobacillus and xvii yeast isolates. The fungicide tolerance of potential antagonistic isolates viz Lactobacillus and yeast isolates revealed that all yeast isolates were tolerant to both fungicides at the highest concentration (2000ppm). It was however, observed that the percentage inhibition increased as the concentration of the fungicide was increased. Similarly, Lactobacillus isolates were found to be tolerant to both fungicides under all concentration treatments. Therefore, the results of the study imply that these antagonists could be used to control mango anthracnose disease integrated with low dosage of these fungicides as part of integrated management of mango anthracnose disease. This study contributes a novel report on the biocontrol of mango anthracnose disease by the application of possibly new antagonist Lactobacillus and yeast isolates. Thus, the use of a combination of biological control agents with commercial fungicides as a safe and effective disease management option against the post harvest anthracnose of mango fruits could be recommended	en_US
dc.language.iso	en	en_US
dc.subject	Biology	en_US
dc.title	Biocontrol Potential of Microbial Antagonists against Mango Anthracnose Disease (Colletotrichum gloeosporioides)	en_US
dc.type	Thesis	en_US