Botrytis rot - chemical control

Pre-harvest orchard sprays

In Europe and USA, fungicide sprays applied at blossom time have given some control of Botrytis eye rot in store. In the UK, in trials, similarly timed sprays were ineffective.

  • A pre-harvest spray of Bellis (pyraclostrobin + boscalid) or Switch (cyprodinil + fludioxonil) will give some control of the Botrytis wound rot.

Post-harvest treatment

  • On Bramley, the use of diphenylamine for control of scald will also give some protection against Botrytis rot.
  • Treatment of water with chlorine (see under Penicillium rot) will reduce inoculum levels of Botrytis present in the drench tank water and reduce wound infections due to B. cinerea.
  • It will not control Botrytis present as latent infection.

Avoiding fungicide resistance

  • Tests have shown that 60% of B. cinerea isolates from apple are resistant to benzimidazole fungicides.
  • It is not known whether there are isolates resistant to Bellis (pyraclostrobin + boscalid) or Switch (cyprodonil + fludioxonil).