Combined application of Bacillus subtilis NJ-18 with fungicides for control of sharp eyespot of wheat

• A combined strategy of wheat sharp eyespot control was evaluated.
• Growth of Bacillus subtilis NJ-18 was unaffected by flutolanil and difenoconazole.
• Greenhouse and field tests were conducted to determine the effect of the combinations.
• Various combinations of bacterium plus fungicides had synergistic effects.

Antagonistic bacterium, Bacillus subtilis NJ-18, can biologically control several plant diseases. A combined strategy of wheat sharp eyespot control consisting of B. subtilis NJ-18 and fungicides was evaluated. Greenhouse and field tests were conducted to determine the effect of combining the B. subtilis NJ-18 with the fungicides flutolanil and difenoconazole for the control of wheat sharp eyespot caused by Rhizoctonia cerealis Van der Hoeven. The sensitivity of B. subtilis NJ-18 to fungicides flutolanil and difenoconazole was tested. The growth of NJ-18 was unaffected by flutolanil in a broth medium, and the survival of NJ-18 spores on wheat seed was unaffected by difenoconazole. In greenhouse experiments, disease control obtained with a combination of NJ-18 and either fungicide was better than the control obtained with the bacterium or fungicides alone, and some combinations of bacterium plus fungicide demonstrated a small synergistic effect in reducing disease. Similar results were obtained with repeated field experiments. In addition to providing a highly effective disease control, the use of combinations enabled a reduced level of fungicide application. Overall, the results suggest that the combination of B. subtilis strain NJ-18 and flutolanil or difenoconazole represents a promising new tool for the control of sharp eyespot of wheat.

Figure optionsDownload as PowerPoint slide