Control of Botrytis cinerea in grape using thyme oil

Control of Botrytis cinerea Pers. leaf colonisation and bunch rot in grapes with oils was studied in laboratory and field tests. In detached lateral e xperiments, the essential oils from thyme (Thymus vulgaris L.) and clove (S yzygium aromaticum L.), as well as massoialactone (derived from the bark of the tree Cryptocarya massoia R. Br.) were not phytotoxic on leaves at conc entrations of 0.33% or less. B. cinerea sporulation on artificially induced necrotic leaf lesions was significantly reduced by thyme (Thyme R) and mas soialactone oils at 0.33%. A single application at veraison (1997/98) of ei ther compound at concentrations of 0.33% controlled bunch rot and necrotic leaf lesion colonisation by B. cinerea compared with Botrytis control treat ments. Spray applications of Thyme R oil (0.33%) at 8-10 day intervals (199 8/99) from flowering to harvest controlled B. cinerea bunch rot but also ca used floral tissues to senesce. Future research and potential applications of thyme oil are discussed.