Scoping study on the non-botrytis bunch rots that occur in Western Australia
Abstract
Scoping study on the non-botrytis bunch rots that occur in Western Australia.
Summary
This study was aimed at determining the presence and impact that non-Botrytis bunch rots are having in Western Australian vineyards. Bunch rots remain a significant burden to the WA wine industry and with the expansion of the industry in recent years there is the potential that non-Botrytis bunch rots are having a major impact. With new research being performed in Australia this study also presented the opportunity to inform and educate growers about non-Botrytis bunch rots.
A survey of 24 vineyards was conducted in the Perth hills (2), Margaret River (6), Swan Valley (5), Pemberton (5), Blackwood valley (1) and Great Southern (5) to determine the incidence and severity of non-Botrytis bunch rots in WA. For the survey, white varieties were chosen between verasion and harvest.
The 2006/07 vintage in WA was considered “atypical” due to a lack of rainfall at critical growth periods and high temperatures leading to early harvests. With the vintage being so early it is difficult to determine what impact this had on the bunch rot development this season and therefore further surveys are required.
Botrytis cinerea was the most prominent fungal species recorded throughout the survey and remains the most destructive bunch rot in WA. Several other fungi including, Aspergillus spp., Penicillium spp. and Alternaria spp. were also frequently isolated. Botryosphaeria berry rot was also recorded in this study and was found in more vineyards than expected. The impact Botryosphaeria species are having as a bunch rot in WA is uncertain at present and needs to be investigated further.
Two seminars were presented in the Margaret River and the Swan Valley regions to provide information to growers regarding research undertaken on non-Botrytis bunch rots. The seminars were attended by Associate Professor Chris Steel from Charles Sturt University who gave the growers the opportunity to ask questions regarding non-Botrytis bunch rots and their management.