Fungicide Resistance

Fungicide use in apple production can be intensive and the range of fungicides available for control is often limited to a few fungicide groups, increasing the risk that fungal strains may arise or be selected which are resistant or less sensitive to the fungicides, leading to reduced control or control failure.

Fungal diseases which readily develop strains resistant to fungicides include:

  • Botrytis cinerea
  • Apple scab (Venturia inaequalis)
  • Penicillium expansum
  • Gloeosporium sp.
  • Colletotrichum spp.

Fungicides are at risk from fungi developing less sensitive or resistant strains because their mode of action works on a single site in the target fungi.

Fungicides at risk from fungal resistance

Summary of main apple diseases and fungicide resistance

Further reading