Bunch Rot

South Africa ranks eleventh in the world for grape production. Wine is South Africa’s biggest agricultural export, earning R2.2 billion in foreign exchange annually. South African farmers also produce about 1.8 million tons of table and dry grapes annually. The industry is primarily export oriented with up to 90% of the total production being exported with a value of R1.5 billion per year. The majority of South African grapes are available in northern hemisphere countries during their winter and spring seasons. Fungicide spray programs are commonly applied in South African vineyards to control Botrytis bunch rot.

“Botrytis cinerea Pers: Fr. is a common, destructive pathogen causing grey mould. …In South Africa, this is an economically important disease on grapevines. …In table grape production, the most serious damage is the loss of fruit quality due to pre-harvest or post-harvest berry rots. …In wine grape production, the fungus causes a serious decrease in quality of juice and wine. Wines produced from B. cinerea infected berries have off-flavours and are sensitive to oxidation and bacterial contamination, making them unsuitable for ageing.

Chemical control is the main way to reduce grey mould on crops. Producers in South Africa invest heavily in chemical products and routine spray applications each year.”

Authors: van Zyl, S. A., et al.
Affiliation: Department of Plant Pathology, University of Stellenbosch, South Africa.
Title: The use of adjuvants to improve spray deposition and Botrytis cinerea control on Chardonnay grapevine leaves.
Source: Crop Protection. 2010. 29:58-67.