Document Type : Pest Management
Authors
1 Plant Protection Research Department, West Azarbaijan Agricultural Research, Education and Extension Center, AREEO, Urmia, Iran.
2 Plant Protection Research Department, Golestan Agricultural Research, Education and Extension Center, AREEO, Gorgan, Iran.
3 3- Associate professor, Department of Agriculture, Medicinal Plants and Drugs Research Institute, Shahid Beheshti University, Evin, Tehran, Iran.
Abstract
In this research, the possibility of mass production and formulation of bacterial isolate Bacillus subtilis B2 with antagonistic activity against powdery mildew of cucumber were investigated. In order to optimize the culture medium, screening of different carbon and nitrogen sources was performed using Design Expert® software. Base of the central composite design, optimal concentration of beet molasses and Corn steep liquor (CSL) in the culture medium to produce maximum bacterial cell biomass was 4.45-6 and 3.82-6 g/liter, respectively. Base on the optimization of environment factors, the maximum bacterial biomass was obtained at a temperature of 32 °C, a stirring speed of 90 rpm, 3.5% of inoculums and pH of 6. Subsequent the biomass production, additional research was carried out with the objective of formulation the bacterial isolate. Totally 18 different formulations prepared with different carriers and adjutants. After six months storage at 4 °C and 24°C the highest population of B. subtilis B2 was in formulation No. 3 (containing sodium alginate and trihalose) with 7.9×108 and 4.2×107 CFU per gram of formulation stored at 4 °C and 24 °C respectively. Based on with highest shelf life, the best formulation of B. subtilis selected for investigation under greenhouse conditions to evaluate the ability of formulations to control powdery mildew of cucumber. Results showed B. subtilis formulation and Dumark fungicide reduces the disease severity by 45.42% and 46.53%, respectively that there is no significant difference between them.
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