Evaluation The efficiency of a Azotobacter vinelandii and some chemical compounds in control of Macrophomina phaseolina The causel agent of charcoal disease under lab and field conditions
M.A.AL-Mousawy K.S.Jaber Department of Plant Protection / College of Agriculture / University of Baghdad
abstract:-
This study aimed to isolation and identification the causal of root and stem rot disease of cowpea in some governarates in the middle of Iraq, testing the pathogenicity of its isolates and evaluating the efficiency of the bacteria Azotobacter vinelandii (AV1) and some chemical compounds in its control .The results of isolation and identification showed the existence of the fungus Macrophomina phaseolina in the samples collected from Karbala ,Baghdad, and Babylon governerate in percentage of existence ranged 17.50-35.00% ,and identified to genus and species level on the bases of cultural and morphological characteristics ,results also showed that the fungal isolate MP which tested on cowpea seed ,had the superiority which reduced seed germination to 30 % compared with 90% in control treatment .the results of isolation and identification of bacteria from soil led to obtain three isolates of bacteria A.vinelandii depending on cultural,microbial and biochemical characteristics, the lab. antagonistic activity test of this bacteria cultured on PDA media indicated that this bacteria possessed higher antagonistic activity against M.phaseolina which gave percentage of inhibition ranged 81.66-86.52% . The results of evaluation chemical compunds and bacteria A.vinelandii in the controlling of M.phaseolina under field conditions indicated that all treatments increased the germination percentage ,reduction in disease incidence and severity of disease and increased plant yield . The germination in all the control treatment ranged 61.46-94.79% with the superiority of AV1 as alone which gave 94.79% and less percentage of infection and severity 0.00% compared with M.phaseolina isolate individualy which gave 12.50% seed germination with the 100% infection and 85.00% severity .The plant yield in AV1 treatment was 674.44gm/plant compared with 17.1gm/plant in the treatment of pathogenic fungus only .
