Preventing/minimizing development of resistance in fungal plant pathogens to fungicides

Development of resistance in fungal pathogens to fungicides has resulted in ineffectiveness of many fungicides for managing plant diseases. Preventing/minimizing development of resistance in plant pathogens to fungicides will be discussed. Based on the modes of action, more than 500 fungicides for managing plant diseases have been placed in 58 groups by the Fungicide Resistance Action Committee (FRAC), which are known now as FRAC groups. Some of the FRAC groups have more than 20 fungicides with different names but the same mode of action. Continuous using of any member of the same fungicide group results in developing resistance in the pathogens against all members of the group. FRAC grouping and FRAC Codes are available for all fungicides, bactericides, and nematicides. Another way of grouping fungicides is placing them in four groups of developing resistance in pathogens, including High Risk, Medium Risk, low Risk, and No Risk. Also based on the resistance development, fungal pathogens have been placed in three groups of High Risk, Medium Risk, and Low Risk. Developing resistance in a pathogen with High Risk managed with a fungicide with High Risk is nine times higher than using a fungicide with Low Risk for managing a pathogen with Low Risk. For avoiding/minimizing resistance development in pathogens to fungicides, consult with a professional plant pathologist with research programs.