Formulation of Psedomonas fluorescens SP007s to control Chinese kale diseases in farming production

Pseudomonas fluorescens SPOO7s isolated from cauliflower rhizosphere that showed antagonistic activities against brassicaceae diseases caused by fungi and bacteria was developed for formulation research. Production of SPOO7s bacterial cells was investigated in 1-liquid and 5-solid formulations with its 2.8 x 10 sup 12 cfu/ml initial population. Different substrates of nutrient sources and carriers including glucose, soybean meals, fish meals, molasses, chitosan, calcium carbonate, FeSO4-7H2O, talcum, soil particles, and CMC (carboxymetyl cellulose) were tested for appropriate component of biocontrol agent. Liquid and solid formulations were inoculated with 10 ml cell suspension of SPOO7s, sealed and incubated at room temperature (27-30 deg C) for 30 days. The efficacy of these 6 formulations in sustaining SPOO7s population and enhancing biocontrol activity was assessed in RCBD [randomized complete block design] experiment of Chinese Kale field production at Suphanburi during June to September, 2007 using each formulation for both seed and foliar (sprayed at 14, 28 and 35-day old plants) application methods totalled 9 treatments compared with SPOO7s fresh cells produced in NB, a standard fungicide (copper hydroxide) and nontreated control. Seed treatment with most of solid formulations as well as with copper hydroxide significantly (P less than or equal to 0.05) increased seedling stand, plant height and fresh weight compared with non treated seeds in non-pathogen infested soil of 28-day old plants. The talcum-based product in the proportions of 1:1:1:1%:1%, wt/ wt/ wt/ vol/ vol with substrate component of talcum/glucose/soil particles/calcium carbonate/ cmc/ FeSO4 7H2O was significantly most effective formulation (P less than or equal to 0.05) in enhancing seedling vigor and resulting 86.4 and 85.4% reduction of black rot (caused by Xanthomonas campestris pv. Campestris) and downy mildew (Peronospora parasitica), the most serious diseases of chinese kale, with highest yields procured of 16.07 t/ha. The reduction of these 2 diseases, and yields obtained from SPOO7s fresh culture cells, and conventional grower plots however, were 61.9 and 33.5%, and 15.8 t/ha, and 15.5 and 16.8% and 12.7 t/ha, respectively. This study demonstrates that carriers and nutrient sources significantly affected SPOO7s biocontrol efficacy.