Demonstration of best practice Botrytis control strategies on a vineyard in the Alpine Valleys region of Greater Victoria

Abstract

Demonstration of best practice Botrytis control strategies on a vineyard in the Alpine Valleys region of Greater Victoria

Summary

Botrytis is one of the most important sources of economic losses on Alpine Valleys vineyards. This project was one of three similar RITA funded projects (in three different regions) all having the same objectives, to demonstrate, assess and refine best practice Botrytis management strategies in a vineyard. The Greater Victoria Wine Grape Industry Development Committee (IDC) instigated as a two year project the Best Practice Botrytis Initiative by the IDC, GWRDC, Monash University and the Department of Primary Industries, along with the three regional associations, as co-investors. The aims of the broader project are, by June 2004, to develop and extend best practice Botrytis management strategies to all wine grape growers across Greater Victoria.

This project successfully adapted the latest national research on Botrytis to vineyards in the Alpine Valleys– Kiewa River Valley, Owens Valley, Myrrhee Valley and Whitlands Valley–in the management of Botrytis. Growers were involved in commenting upon, and adding to, a checklist of prompts that highlighted actions that could be implemented in the vineyards in the Alpine Valleys where Botrytis is a major problem. Growers from the three regions expressed a need for a document to accompany the checklist explaining more fully the reason(s) for the actions suggested. The checklist and the accompanying document and CD will be available in early 2004.

Information days held at the Smith Bros. vineyard allowed data to be presented by the researchers and growers to be actually involved in assessing the checklist and providing feedback on its relevance to them.

Bunch thinning (the management option selected for this vineyard) to 30-40 bunches per vine from up to 90 bunches per vine, reduced congestion and allowed for good ripening and harvest of high quality fruit.

The drought during the summer of 2002-2003 was instrumental in lower than normal expression of Botrytis, so management strategies implemented on the Smith Bros vineyard have not been tested under high disease pressure conditions. However, all berry samples taken from this vineyard were Botrytis infected. Because of the dry weather at harvest, there was no Botrytis expression and perfect bunches were harvested. This outcome provides evidence that it is Botrytis expression, rather than Botrytis infection, which is a key issue at harvest.