Highlights from the Fungicide Resistance Tailgate Meeting

  • Populations of powdery mildew (PM) become resistant to a fungicide from repeated exposure to the same material over time
  • Resistance is often attributable to differences in a single gene between members of the population.
  • Once exposure to that particular fungicide ends, the diversity of the PM population drifts back to being primarily susceptible.
  • Different types of fungicides (FRAC groups) work by interfering with or inhibiting a particular biological pathway.
  • PM populations resistant to FRAC 11 fungicides (strobulurins) are wide spread on the West Coast.
  • There is a robust molecular genetic technique to monitor resistance.
  • There might be potential to rejuvenate FRAC 11 fungicides (strobulurins).
  • Molecular tools could develop a fungicide stewardship program.
  • Populations of PM resistant to FRAC 11 fungicides can be identified by diagnostic labs now using molecular genetic methods.
  • PM populations resistant to FRAC 3 (DMI) fungicides are widespread.
  • There is a molecular genetic tool that can detect resistant population.
  • This tool is not quite ready to be released to diagnostic clinics/laboratories.
  • Control failures and resistance to FRAC groups 7 and 13 and have been reported.
  • Further investigation is required.
  • How far and how fast does fungicide resistant PM move? We don’t know, but it is being investigated.

Additional Resources