Evaluation Activity of Some Antimicrobial Agents in Reduction Microbial Load and Their Impact on Vase Life of Asparagus aethiopicus L.

The short vase life is a major problem in the Asparagus aethiopicus leafy cut stem industry. The present study showed that several bacterial and fungal species were found to be associated with A. aethiopicus cut wilted stems and their vase life. This included six bacterial species, i.e., Bacillus subtilis, Bacillus sp., Pseudomonas sp., Streptococcus sp., Streptomyces sp. Streptobacillus sp. and also five fungal species, i.e., Alternaria alternata, Fusarium oxysporum, F. solani, Aspergillus flavus and A. niger. However, Pseudomonas sp. and F. oxysporum were the most frequent bacterial and fungal microorganisms. Three tested antimicrobial agents, i.e., 8-hydroxy quinoline citrate (8-HQC), sodium hypochlorite and citric acid significantly reduced number of bacterial and fungal proliferation in the different vase treatments wherestems basal ends were dipped in them and this effect was increased with increasing their concentrations. However, 8-HQC at 200 ppm + oxytetracycline hydrochloride (1000 ppm) showed reduction percentages of 84.29 and 51.72 % of bacterial and fungal numbers, respectively. Also, sodium hypochlorite at 10 ppm + oxytetracycline hydrochloride (1000 ppm) recorded bacterial and fungal reductions that reached 85.25 and 42.44%, respectively. This was followed by citric acid (1000 ppm) + oxytetracycline hydrochloride (1000 ppm) which showed 83.31and 28.32 %, reductions of bacterial and fungal numbers while antimicrobial agents’ treatments without oxytetracycline hydrochloride showed lower reduction effect.All antimicrobial agents’ treatments succeeded to decrease weight loss and enhanced water uptake and vase life of the treated A. aethiopicus cut stems and this effect was increased with increasing their concentrations. Meanwhile, treatment with the mixture of 8-HQC (200ppm) + oxytetracycline (1000 ppm) was the most effective treatment in decreasing cut stem weight loss to be low as 4.05 % compared to 44.37 % for the untreated control. Also, this treatment enhanced water uptake and vase life to be as high of 44.90 g and 14.50 days compared to 16.81 g and 5.44 days of the control treatment in the previous parameters, respectively. This was followed by the mixture of sodium hypochlorite (10 ppm) + oxytetracycline hydrochloride (1000 ppm) and citric acid at (1000 ppm) + oxytetracycline hydrochloride (1000 ppm) treatments.