Fungi Associated with the Spoilage of Sweet Orange (Citrus sinensis) Fruits and their Management by Bio-Control Agents

Abstract

Different Sweet Orange fruits (Citrus Sinensis) rot fungi were isolated from rotted fruits.These were Aspergillus niger, Aspergillus flavus, Aspergillus fumigatus, Penicillium digitatum. During pathogenicity test two fungi Aspergillus niger and Penicillium digitatum were proved to be most pathogenic. The Aspergillus niger fungi during dual culture with Bacillus substilis, Bacillus substilis srtain2,  Pseudomonas fluorescens, Pseudomonas aeruginosa , Bacillus methylotrophicus, Bacillus cereus, Bacillus aryabhattai  and Streptomyces strain  showed different level of  inhibation zones.  Bacillus cereus was the most effective and caused 71.5% inhibition and Pseudomonas aeruginosa was least 53.28% and others Bacillus substilis, Bacillus substilis srtain2, Pseudomonas fluorescens, Bacillus methylotrophicus , Bacillus aryabhattai ,and Streptomyces caused 68.05%, 64.00%, 70.25%, 59.37%, 57.75% and, 55.25%, respectively. Penicillium digitatum fungi during dual culture with Bacillus substilis, Bacillus substilis srtain2,  Pseudomonas fluorescens, Pseudomonas aeruginosa , Bacillus methylotrophicus, Bacillus cereus, Bacillus aryabhattai  and Streptomyces strain  showed different level of  inhibation zones. Bacillus cereus was the most effective and caused 69.25% inhabition and Pseudomonas aeruginosa  was least 51.75% respectively. During experiment on fruits the most effective biocontrol agent Bacillus cereus and Streptomyces strain  were tested on fruits and it was found that Bacillus cereus and Streptomyces strain  were effectively control the rot by Aspergillus niger and showed data 49.45%, 43.55%. During experiment on fruits the most effective biocontrol agent Bacillus cereus and Streptomyces strain  were tested on fruits and it was found that Bacillus cereus and  Streptomyces strain  were effectively control the rot by Penicillium digitatum and showed data (51.62%, 45.67%). Experiment were performed for protective and curative effects. During protective effect the two biocontrol agents Bacillus methylotrophicus and Bacillus cereus reduced the percentage rottenig by 64.74% and 57.52% respectively in case of Aspergillus niger and in case of Penicillium digitatum the effect of two  Biocontrol agents Bacillus methylotrophicus and Bacillus cereus caused 59.37% and 54.63%  respectively reducuction in decaying. During the Curative effect the two biocontrol agents Bacillus methylotrophicus and Bacillus cereus reduced the rottenig percentage 62.53% and 55.84% respectively in case of Aspergillus niger but in case of Penicillium digitatum the effect of the  Biocontrol agents Bacillus methylotrophicus and Bacillus cereus caused 58.29% and 51.99%  respectively  reducuction in decaying. Use of Biocontrol agents as protective is better than the curative.