Molecular diagnosis of Rhizoctonia solani Kühn Caused of melon root Cucumis melo L. and its Biological control

Abstract

The results of isolating from the infected plant parts showed the obtaining of 9 isolates of the Rhizoctonia solani, which is dignosis based on its taxonomic characteristics. The fungal diagnosis was confirmed by polymerase chain reaction (PCR) technique to diagnose. The results of the pathogenicity of the isolates R. solani differed in their ability to disease of radish and the melon seeds. The study showed that B. subtilis had a high degree of resistance of inhibiting the growth of pathogen R. solani, where the rate of inhibition was between (72.96 - 85.92%). T. harzianum was highly resistant to R. solani isolates, with the percentage of inhibition ranged from 78.99 to 93.66%. The results of the wooden canopy showed that all treatments reduced the percentage and severity of melon root rot disease and significantly improved plant growth. the treatment of T. harzianum, B.subtilis and Salicylic acid, decreased the disease incidence and severity into 11.1% and 2.22% respectively. All treatments caused significant increase in plant growth parameters compared to the treatment of pathogenic fungi alone.