Incidence of grapevine bunchstem necrosis in South Australia: effects of region, year and pruning

Abstract

The incidence of grapevine bunchstem necrosis (BSN) in cv. Cabernet Sauvignon was assessed in three South Australian regions during three years. The percentage of bunches affected varied widely—from nil to 26%-between years and regions. At the site with most BSN, high incidence was related to lower temperatures during 20 days before flowering and not to low temperatures during flowering. Also, incidence was higher when rain fell during veraison. Minimally pruned vines had significantly less BSN than spur-pruned vines in each of the three test years.