POST HARVEST DISEASES OF SOME SELECTED SALAD VEGETABLES, THEIR CAUSES AND MANAGEMENT

Abstract

A study was conducted to observe the post harvest diseases of some selected salad vegetables and to identify their causes. The experiment was conducted in the MS Laboratory of Department of the Plant Pathology, Faculty of Agriculture, Sher-eBangla

Agricultural University during the period from March, 2019 to March, 2020. Samples were collected from local markets of Dhaka city. In this study, seven different fungal species and four different bacterial strains were isolated. Aspergillus rot (Aspergillus niger and Aspergillus flavus), cottony soft rot (Sclerotinia sclerotiorum), fusarium rot (Fusarium sp), sour rot (Geotrichum candidum), anthracnose (Colletotrichum capsici), green mold (Trichoderma sp) and bacterial soft rot (Serratia marcescens, Bacillus sp and Pseudomonas sp) diseases were identified. Fungi were isolated by growing them in moist chamber and PDA medium. Bacteria were isolated by dilution plate method and growing them in NA medium by spread plate method and streak plate method. Bacteria were identified by studying the morphological and cultural characteristics and performing several biochemical tests like Gram-staining test, KOH solubility test, oxidase test, catalase test, motility test, citrate utilization test, casein hydrolysis test, lactose fermentation test, sucrose fermentation test, dextrose fermentation test. Bacillus agar and citrimide agar medium were used to separate Bacillus and Pseudomonas, respectively. Pathogenicity test of some pathogens were also performed. Identification of the bacteria from cucumber was further confirmed by extracting DNA from the bacterial cultures. The samples were subjected to PCR using 27F and 1492R primers. The D1/D2 of 16S rDNA sequences of Serratia marcescens isolates were submitted to NCBI for deposition in the GenBank and accession number. The provided accession number MW404210 for Serratia marcescens strain SAU-1. Effects of different storage containers on different vegetables and their microbial growth were also observed.