Trichoderma harzianum and T. viride as well as Pseudomonas fluorescens , P. putida and Bacillus subtilis were evaluated as bioagents against Macrophomina phaseolina, the causative pathogen of sunflower charcoal rot. No in vitro adverse interaction could be recognized among the tested Trichoderma isolates and both P. fluorescens and B. subtilis. The highest antagonistic effect against M. phaseolina was recorded by B. subtilis as decrements in mycelial growth and sclerotial numbers. Similar effect was recorded for T. viride and P. fluorescens. In greenhouse and field experiments, T. viride and P. fluorescens and B. subtilis, along with the biocide (Rhizo-N) and fungicide (Rizolex-T) decreased the disease incidence.
In this respect, T. viride mixed with either B. subtilis or P. fluorescens revealed greater effect in disease control compared to the single application of any of them, especially with mixed B. subtilis treatment. The effect of the later showed disease control approximately similar to that of Rizolex-T treatment, as shown by healthy survivals and seed yield over two years study.