Mark Krasnow,* Allison Haywood, Finn Horsfeld, Alex VanSarloos, and Mark Allen
*Thoughtful Viticulture Ltd., PO Box, 312, 7201, New Zealand (thoughtfulviticulture@gmail.com)

Crop losses due to Botrytis cinerea bunch rot can be significant in cooler-climate vineyards, such as those in New Zealand. Using a mechanical harvester to shake the vines between set and bunch closure reduces the severity of rot at harvest by ~50%. Harvester settings can be chosen to shake hard enough so that crop is removed, or for a lighter shake so that the crop is maintained, but “floral trash” (unpollinated berries, caps, and anthers) is removed from the bunch. This reduces the potential Botrytis inoculum present inside bunches as they ripen. There is evidence that the shaking, in addition to removing floral debris, induces tougher skins and a biochem­ical defensive response within berries. All of these would reduce Botrytis infection and/or spread within the bunch. Benefit can be gained from shaking soon after set (5 to 10 g bunches) all the way through to bunch closure (40 to 50 g bunches). Mechan­ical shaking offers a cost-effective, sustainable, and nonchemical means to protect fruit from bunch rot losses. This practice is already commonplace in New Zealand vineyards, but offers great promise in other winegrowing regions, especially those that receive rain around harvest and where bunch rots are a common problem.

Funding Support: New Zealand Winegrowers