STUDIES ON ROOT ROT OF MANGO SEEDLINGS
KHALED MOHAMED ABD El-GHANY;
Abstract
ABSTRACT
Disease survey in the nurseries of mango seedlings indicated that root rot was present in all grown areas at different governorates. The highest percentage of isolated microorganisms was obtained from Gharbia governorate, while the lowest one was found at Fayoum governorate. The most prevalent organisms were Botryodiplodia theobromae, Rhizoctonia solani and Fusarium solani. The three fungi proved their pathogenicity. Evaluation of three varieties of mango against the three pathogens causing root rot disease revealed that Zebda and Hindy were highly susceptible, while Alphonse was less susceptible. The three pathogenic fungi were able
in. t
to produce PME, PG and Cx in vitro and in vivo experiments but at
different degrees. Disease incidence was more in sandy soil than clay and calcareous soils. In the meantime, increasing of water salinity increased disease occurrence. Determination of some biochemical changes due to infection showed that healthy mango var. Zebda contained higher amount of total sugars and total phenols than var. Alphonse. The infection of var. Zebda caused an in increase in total sugars content than that in Alphonse one, while the infection caused an accumulation of phenols in the var. Alphonse than Zebda one. Histopathological studies of several transverse sections from artificially infected mango roots revealed that B. theobromae caused plasmolysis and disorganization with a black discoloration of epidermal and cortical cells, in case of R. solani caused separated the epidermal cell from the cortical cell and disorganized them, in the meantime, F. solani caused collapsed and disintegrated of cortical cells, chlamydospores were found inside the cortical cells and in xylem vessels. All the tested fungicides decreased the fungal growth in vitro and disease percentage in vivo, Vitavax-Thiram was the best fungicide, while Monceren was the lowest. Two bioagents namely, Trichoderma koningii and Bacillus coagulans showed an antagonistic effect. Also, the two bioagents reduced the infection percentage. Addition of two bioagents one week before applying the pathogens was the most affective.
Disease survey in the nurseries of mango seedlings indicated that root rot was present in all grown areas at different governorates. The highest percentage of isolated microorganisms was obtained from Gharbia governorate, while the lowest one was found at Fayoum governorate. The most prevalent organisms were Botryodiplodia theobromae, Rhizoctonia solani and Fusarium solani. The three fungi proved their pathogenicity. Evaluation of three varieties of mango against the three pathogens causing root rot disease revealed that Zebda and Hindy were highly susceptible, while Alphonse was less susceptible. The three pathogenic fungi were able
in. t
to produce PME, PG and Cx in vitro and in vivo experiments but at
different degrees. Disease incidence was more in sandy soil than clay and calcareous soils. In the meantime, increasing of water salinity increased disease occurrence. Determination of some biochemical changes due to infection showed that healthy mango var. Zebda contained higher amount of total sugars and total phenols than var. Alphonse. The infection of var. Zebda caused an in increase in total sugars content than that in Alphonse one, while the infection caused an accumulation of phenols in the var. Alphonse than Zebda one. Histopathological studies of several transverse sections from artificially infected mango roots revealed that B. theobromae caused plasmolysis and disorganization with a black discoloration of epidermal and cortical cells, in case of R. solani caused separated the epidermal cell from the cortical cell and disorganized them, in the meantime, F. solani caused collapsed and disintegrated of cortical cells, chlamydospores were found inside the cortical cells and in xylem vessels. All the tested fungicides decreased the fungal growth in vitro and disease percentage in vivo, Vitavax-Thiram was the best fungicide, while Monceren was the lowest. Two bioagents namely, Trichoderma koningii and Bacillus coagulans showed an antagonistic effect. Also, the two bioagents reduced the infection percentage. Addition of two bioagents one week before applying the pathogens was the most affective.
Other data
| Title | STUDIES ON ROOT ROT OF MANGO SEEDLINGS | Other Titles | دراسات على عفن جذور شتلات المانجو | Authors | KHALED MOHAMED ABD El-GHANY | Issue Date | 2001 |
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