Synergistic Effect of Combined Application of a New Fungicide Fluopimomide with a Biocontrol Agent TA-1 for Management of Gray Mold in Tomato.

Gray mold caused by can be a severe disease of tomato infecting leaves and fruits of tomato plants. Chemical control is currently the most effective and reliable method; however, application of fungicides has many drawbacks. The combination of biological control agents with newly developed fungicides may be a practicable method to control . Fluopimomide is a newly developed fungicide with a novel mode of action. TA-1, isolated from rhizosphere soil of tomato, is a bacterial strain with a broad spectrum of antimicrobial activities. Little information is currently available about the effect of fluopimomide and its integrated effect on . Therefore, laboratory, pot, and field experiments were carried out to determine the effects of fluopimomide alone and in combination with TA-1 against gray mold on tomato. The in vitro growth of TA-1 was unaffected by 100 mg liter fluopimomide. Inhibition of mycelial growth was significantly increased under combined treatment of fluopimomide and TA-1. In greenhouse experiments, efficacy against gray mold was significantly greater by an integration of fluopimomide and TA-1 than by either alone; control efficacy of fluopimomide at 50 and 100 g ha in combination with TA-1 at 10 colony-forming units (cfu) ml reached 70.16 and 69.32%, respectively, compared with the untreated control. In both field trials during 2017 and 2018, control efficacy was significantly higher for the combination of fluopimomide at 50 and 100 g ha in combination with TA-1 than for either treatment alone. The results from this study indicated that integration of the new fungicide fluopimomide with the biocontrol agent TA-1 synergistically increased control efficacy of the fungicide against gray mold of tomato.