Effect of Cultural Methods on the Occurrence of Grey Mould (Botrytis cinereaPers.) in Strawberries

Two alternatives to chemical control of Botrytis in strawberries were assessed, post-harvest defoliation and finger harrowing, the latter being used primarily in weed control but also claimed to affect the occurrence of Botrytis. Post-harvest defoliation, though having some positive effect on marketable yield, did not reduce the incidence of Botrytis significantly. This was the case regardless of whether or not cut leaf material was removed from the plots. Finger harrowing, though in some instances having a negative effect on yield, did not control Botrytis significantly either. However, it was clearly demonstrated that, in organic strawberry growing, the incidence of Botrytis increases with plant age. Therefore, a short-term cropping system may be more important in controlling Botrytis than either post-harvest defoliation or finger harrowing. In conclusion, the combined use of several cultural methods may be needed when controlling Botrytis in organically grown strawberries.