EFFECT OF SOME ANTAGONISTIC BACTERIA IN REDUCING OF PEANUT DAMPING - OFF, ROOT AND POD ROT INCIDENCE CAUSED BY Rhizoctonia solani

Seventeen bacterial isolates from the soil, rhizosphere, geocarposphere, peanut roots and pegs beside three supplied bioagents (Bacillus subtilis, Pseudomonas putida and Pseudomonas fluorescens) used to study their effect on four isolates of Rhizoctonia solani. In vitro only nine isolates caused moderate to strong inhibition to the four tested isolates of R. solani. P. fluorescens (Pf.5) gave the highest significant antagonistic effect against the four tested isolates of R. solani on PDA medium followed by B. subtilis (Bs.1), P. putida (PP) and Bacillus sp (S.5). In greenhouse and field experiment, the most effective isolates in reducing peanut damping-off, root and pod rot diseases were P. fluorescens (Pf.5) followed by B. subtilis (Bs1) and Bacillus sp (S.5). Regarding to peanut pod yield, the highest total peanut pod yield in the two seasons (2009 and 2010) was obtained by B. subtilis (Bs1) followed by P. fluorescens. The obtained data clearly showed the ability of some tested bioaegents to be near to the fungicides effect (Rezolex-T) in reducing damping-off and peanut root and pod rots diseases. In this respect, in greenhouse and field trials P. fluorescens (Pf 5.) was the nearest one to fungicides effect in reduction of peanut damping-off and peanut root and pod rots and exceeded the commercial biocide effect (Rhizo-N), followed by Bacillus sp (S.5) and B. subtilis (Bs1) compared to other tested bioagents.