journal of kerbala university

The present this study was carried out in 2012 at the College of Agriculture ,Kerbala,Iraq to estimate tomato early blight disease and to test the efficacy of some methods for controlling it. Isolates of the pathogenic fungus Alternaria solani were obtained and their pathogenicity was tested. The effect of two isolates of plant – growth promoting bacteria, Enterobacter cloacae , Pseudomonas fluorescens, the biological fungicide EMI on the disease persentage and intensity was tested as well .The isolates of A. solani were collected from plants bearing disease symptoms in different regions of Baghdad,Kerbala and Babylon provinces . The pathogenesity of 12 isolates of A. solani showed different levels of infection on raddish seed . The germination rates of these seed infacted by these isolates varied from 15% to 80% compared with 90% in control treatment. According to this test , the most infective isolate was given the symbol As5 and then used later in all following experiments. The results of antagonism test showed high effect of P. fluorescens and E. cloacae isolates against A.solani in acultural medium of potato dextrose agar (PDA) . The rates of fungus growth inhibition caused by these isolates reached 83% and 56% , respectively these isolates were used at the concentration of 1x610 . The use of P. fluorescens , E. cloacae , EMI and Beltanol causded increase in tomato seed germination rates after two weeks under protetive culture condition . The use of P. fluorescens and E.cloacae caused significant reduction in percentage disease infection in tomato seedling after 45 days of planting . these percentages reached 13.33%and 6.66% in those treatments ,respectively compared with 93.33% in treatment of pathogenic fungus. The infection intensity rates of the disease reach 6.56%,4.42% and 39.21% in the aforementioned treatments , respectively . The use of the biological fungicide EMI reduced the disease infection percentage in tomato seedlings whereas the use of the synthetic fungicide Beltanol resulted in complete inhibition of the disease pathogen