Workshop – Planning research toward sustainable management of bunch rots in grapes

Abstract

Workshop - Planning research toward sustainable management of bunch rots in grapes

Summary

Bunch rot of grapevine, caused by Botrytis cinerea and other opportunistic plant pathogens, continues to be managed by the wine industry with mixed success. Management of this disease is complex requiring multiple, integrated approaches. Effective application of protective fungicides during flowering depends on appropriate spray dose, timing and coverage in relation to the incidence of moisture and establishment of latent infection. For most sites and years, it is not known if applications of protective fungicide during flowering contributed significantly to a reduction in the severity of bunch rot at harvest. A false sense of security can develop when protective fungicides appear to work well in years that are unfavourable for the expression of bunch rot.  Hence, this form of crop insurance continues, despite the potential for more strategic applications. A major constraint in bunch rot management is the lack of tolerance for chemical residues in wine destined for various export markets. This has restricted options for late-season control of bunch rot.

Integrated management, based on pathogen activity and reduced reliance on synthetic fungicides, has become paramount. Outcomes of Botrytis research in the last 5-10 years are being adopted by industry through mechanisms such as the Botrytis Checklist. In order to maintain the momentum, twenty researchers and industry proponents from Australia and New Zealand met in Hobart on November 2-3, 2005, to develop a coordinated research strategy for bunch rot of grapevine. The workshop aims, process and outcomes are described in this document.