Biological control of fungal wilt of tomato by plant growth promoting rhizobacteria and Trichoderma harzianum

Abstract

The efficacy of plant growth promoting bacteria i.e. (Bacillus subtilis, Bacillus polymyxa, Bacillus megaterium, Pseudomonas fluorescence, Azotobacter sp.,  Azospirillum sp. and the fungus Trichoderma harzianum were studied  as bioagents for controlling  Fusarium  oxysporum  f.sp. lycopersici and Verticillium dahliae the causing wilt disease of tomato. The results of antagonistic activity of the PGP bacteria against Fusarium oxysporum f.sp. lycopersici and Verticillium dahliae  in vitro  exhibited higher variation  in their abilities to reducing the growth rate of the pathogen and increasing the percentage of pathogen inhibition as compared with the  control treatment. Also, the obtained results showed that Trichoderma harzianum I,  Pseudomonas  fluorescens and Bacillus subtilis gave  the best results  for controlling Verticillium dahliae and Fusarium oxysporum  f.sp. lycopersici. Under greenhouse conditions, the inoculated  tomato seedling  with a mixture of (Azotobacter  sp+ Azospirillum sp.+  B. megaterium var. phosphaticum + B. subtilis+ B. polymyxa +Pseudomonas  fluorescence+ T. harzianum I  showed the  least  percentage  of infection as compared with the  bioagent  treatments  individually.