Biological control of pathogens associated with kernel black point disease of wheat

Pathogens associated with wheat kernel black-point disease were recovered from symptomatic grains and identified as Cochliobolus sativus, Alternaria alternata and Fusarium graminearum. A total of twenty-five microbial isolates obtained from the surface of healthy grains of wheat were screened for antagonism against the isolated pathogens. The most effective antagonistic isolates were Bacillus megaterium (B5), B. amyloliquefaciens (B28), Trichoderma harzianum (T37) and Epicoccum sp. (E52). In pots, treating of wheat grains with strains B5, B28, T37 and E52 significantly improved germination and seedling growth naturally infected with the black-point pathogens. Bacillus amyloliquefaciens (strain B28) was the most efficient biocontrol agent in terms of germination, length of roots and shoots which increased by 103.2, 55.3 and 43.91%, respectively. In field trials, the antagonistic isolates improved germination and tillering of black-pointed wheat grains. Spraying wheat plants with the antagonistic isolates significantly decreased the incidence of leaf-spots and kernel black-point down to 18.7 and 2.86, respectively, with B. amyloliquefaciens (B28). In addition, grain yield was significantly increased. Strain B28 (B. amyloliquefaciens) increased the weight of 1000-kernels by 16.77% and was as effective as the fungicide Sumi-8.