Production and Optimization of <i>Pseudomonas fluorescens</i>Biomass and Metabolites for Biocontrol of Strawberry Grey Mould

Pseudomonas species have been widely studied as biological agents (BCAs) and it is alternative to the application of chemical fungicides. Our objective was to optimize nutritional and environmental conditions of the isolated Pseudomonas fluorescens fp-5 for biomass and metabolites production and to evaluate itsagainst the grey mould disease caused by Botrytis cinerea on strawberry plants under field conditions. Pseudomonas fluorescens, showed antagonistic properties, in vitro, against thepathogen Botrytiscinerea. Effect of the separated secondary metabolites on the fungal growth by broth dilution technique and antifungal activity by agar well diffusion technique was studied. Response surface methodology was used to investigate the effects of four fermentation parameters (pH, incubation time, carbon and nitrogen concentrations) on biomass and bioactivemetabolites [antibiotic phenazin and siderophore] production. Glycerol was found to be the best carbon source for improved biomass and metabolites production. Meanwhile, peptone and yeast extract were found to be the best nitrogen source. Analysis of each formulation revealed that glycerol oil at 0.01% the best oil used for protect P. fluorescens for 3 months Under natural condition, P. fluorescens formulation was effective in reducing B. cinerea disease in strawberry leaves and fruits. Pre-harvest treatment protected fruits from Botrytis post-harvest disease in comparing of fungicide. In addition, the obtained results showed that bacterial treatment significantly increased thegrowth parameters as well as dry weights and yield.

Pilot-scale production and optimizing of cellulolytic <i>Penicillium oxalicum</i>for controlling of mango malformation

Penicillium oxalicum Curie et Thom isolated from blossom of mango (var. Saddekia) was evaluated against mango malformation incited by Fu- sarium subglutinis. Both in vitro and in vivo conditions. The mechanism of this isolate for controlling Fusarium was the reduction of growth development. The Penicillium oxalicum isolate produced extracellular cellulolytic enzymes (exo-glucanase or cellobiohydrolases and endo-glucanase, that possibly related to the biocontrol process. Optimize and fermentation conditions (growth period, carbon and nitrogen sources) for spores and cellulolytic enzymes production were determined. Liquid formulation containing (6 × 106) with sodium alginate (0.5%) and Tween 80 (0.01%) was used. For field evaluation, susceptible cultivars as Ewais, Saddika, Alphonso, Taimour and Zebda were selected. Liquid bioformulations were sprayed twice and 30 days intervals. The spray was initiated from pre-flowering stage. Bioformulation was found to be significant in reducing the malformation incidence. Results cleared that spraying of liquid bioformulations, substantially improved the fruit numbers and yield for the five mango cultivars and suggested to be most promotive for fairly quality in tested cultivars.

Mass production, fermentation, formulation of <i>Pseudomonas putida</i>for controlling of die back and phomopsis diseases on grapevine

The export oriented agricultural and horticultural crops depends on the export of residue free produce and has created a great potential and demand for the incorporation of biopesticides in crop protection. PGPR with wide scope for commercialization includes Pseudomonas putida. Pseudomonas putida was effective in reducing die back caused by a fungus Botryodiplodia theobromae and phomopsis or arm death, caused by a fungus, Phomopsis viticola of grapevine in vitro and in vivo. Pseudomonas putida showed optimum Siderophore pseudobactin production at 72 h, and growth peak at 120 h. glycerol as a source of carbon and yeast as a source of nitrogen Pseudomonas putida was formulated using polysaccharide dextran starch, which led to the elongation of conservation and the effectiveness of the biofungicide. Pseudomonas putida was very effective as biocontrol agents to reduce the die back and phomopsis diseases on grapevine. The obtained results showed that both bacterial treatments significantly increased the growth parameters as well as fruits dry weights and yield of grapevine.

Mango malformation: II. mangiferin changes associated with <i>fusarium</i>pathogens

Mangiferin (1,3,6,7-tetrahydroxy xanthone-C2-b-D-glucoside) promoted vegetative growth and exhibited inhibitory role on the occurrence of malformation. Mangiferin changes associated with mango malformation pathogens were followed after inoculated mango seedlings (three years) with malformation pathogens i.e. Fusa-rium subglutinans, F. sterilihyphosum, F. oxysporum and F. proliferatum. Mangiferin remained at lower level in leaves of malformed shoots as compared to healthy one. The floral malformation was observed to be associated with the reduction of mangiferin. Strong positive correlations between mangiferin activity and malformation incidence were observed. Mangiferin level at panicle initiation may give a possible estimate of malformation incidence in mango.