In vitro inhibition of the mycelial growth of some root rot fungi by Rhizobium leguminosarum biovar phaseoli isolates

Abstract

In solid medium, the effects of twenty-three Rhizobium leguminosarum biovar phaseoli isolates on the mycelium development of the phytopathogenic fungi of three different genera (Fusarium oxysporum, Pythium ultimum and Rhizoctonia solani) were tested in vitro. The experiments were achieved by applying the superimpose dual culture technique. Most of the rhizobia tested inhibited the fungal development. The inhibition rates displayed differences in accordance with the bacteria and fungi isolates utilized. However, the inhibitory effect of the rhizobia occurred most on the isolates of Fusarium and Pythium species (up to 30.35% and 29.75% respectively) and least on those of Rhizoctonia species (16.03%). The most effective Rhizobium isolate on the three fungal species was Rhizobium leguminosarum çar 9.3.2 isolate and percent inhibitions were 14.65-16.03 for R. solani isolates and 14.62-30.35 for P. ultimum isolates and also 14.58-29.75 for F. oxsporum isolates.