BIOCONTROL OF CERTAIN SOILBORNE DISEASES AND PROMOTION OF GROWTH OF CAPSICUM ANNUUM USING BIOFUNGICIDES

摘要

Colored pepper (Capsicum annuum L.) has great economic importance as a food vegetable crop in Egypt and all overthe world. This crop is prone to infection with soilborne fungal pathogens such as Rhizoctonia solani, Fusarium solani andMacrophomina phaseolina. These mycopathogens were isolated from diseased pepper seedlings, identified; their virulencewas confirmed in the greenhouse. Eight bacterial isolates mainly; (Bacillus subtilis and Pseudomonas fluorescens), andmany fungal isolates mainly, (Trichoderma harzianum and T. viride), were isolated from the rhizosphere soil of pepper. Theycaused appreciable In vitro inhibition of the radial growth of the 3 pathogens in dual culture technique, in percentagesranging from (71-79%) and (80-87%), respectively. On infestation of pepper soil with these bioagents and the 3 pathogensseparately in the greenhouse, they caused In vivo reduction of disease symptoms of pepper compared with the pathogensinfested and non-infested control soils. In addition, they caused significant improvement of pepper growth compared withthe control soil, however, promotion exerted by B. subtilis and T. harzianum was more than that of P. fluorescens and T.viride. These promoting activities could be attributed to the production of metabolites such as growth hormones;solubilization of phosphates and improvement of nutrient uptake. This is the first record of promoting the growth of pepperin greenhouse by B. subtilis and T. harzianum in Egypt. Thus these bioagents could be formulated then applied in the futurein pepper fields of this country as safe, effective, ecofriendly biofungicides to control soilborne pathogens and also could beused as biofertilizers to promote the growth and productivity of this crop.