Tendrils as a source of seasonal carryover of Botrytis cinerea in vineyards

Botrytis bunch rot is a disease that requires management under New Zealand conditions in order to prevent financial losses for wine grape producers. A survey was conducted to investigate the potential spore production of tendrils in 16 vineyards from the Marlborough and Hawke's Bay wine growing regions. Significant differences in spore production potential of tendrils were detected between sampling before flowering and after fruit set. Significant regional differences were also detected, with tendrils from Marlborough producing fewer spores. Under ideal laboratory conditions for incubation of the fungus, spore production by tendrils was low at the start of the season and was reduced further following application of the industry standard fungicide programme. Based on these experiments and a review of other data it is recommended that tendril removal is not required at pruning as part of vineyard disease management.