Isolation and Identification of Pathogens Responsible for Post-Harvest Spoilage of Onions (Allium cepa L.) in Some Selected Markets in Maiduguri, Borno State

Abstract

This study aims to identify and isolate pathogens, responsible for post-harvest spoilage of onions (Allium cepa L.) with the following stated objectives: To isolate and Identify pathogens responsible for the onion spoilages, to estimate diseased incidence on spoiled onion, to characterizes effect of leaf extract on the pathogens, to determine whether environmental factor has effect on onion post-harvest handling process by farmers. The data was analyzed using simple percentage. physical characteristic and microscopic characteristics of the isolated pathogens; The survey reviles the diseased incidence on spoiled onion isolated from the sampled onions. Five samples sample were collected from three different markets selected for this study. 13.3 percent of the rotten onion are caused by Penicillium digitatum, Fusarium oxysporum, and Rhizopus stolonifera. which are mainly fungal pathogens and 26.6 percent is caused by Aspergills niger which is also fungi while 26.6 percent Saccaromyces cerevisiae which is bacterial isolate. The distribution of the bacteria in relation to the markets surveyed. The percentage distribution was 64.28% Enterobacter sp, 21.42% Pseudomonas Sp and 14.28% Escherichia coli, respectively. Leaf extract test result of four different disk against standard anti-biotic gentamycin sample. The neem extract shows total 56 mm inhibition area with averagely 28% against the standard sample gentamycin. Bitter leaf extract also shows 54 total inhibition zone with total 27% while African mahogany with highest inhibition zone shows total 62mm inhibition zone with average of 31%. And Aloe vera shows 60mm total inhibition zone with average of 30%. The research also shows that room temperature (29- 30⁰) was the best temperature for development of rot. There was no rot formation at -20⁰C and at 4⁰c while at 37⁰C very little rot developed.