Hunter Valley wine rot), "Greeneria uvicola" (bitter rot) and other fungi from the genera of "Aspergillus, Penicillium" and "Alternaria". Susceptibility of certain wine grape varieties were found to increase as the grapes reached higher Brix sugar levels. Further research in the 2000s, showed that some of the open canopy techniques used to prevent "Botrytis" grey rot may actually promote the development of some of these other types of rot. Ripe rot, in particular, seemed to thrive at the higher ultraviolet B (280–320 nm) light exposure that open canopies allow. To compound the potential problem for Hunter Valley wine growers is that, as of
Yield (wine) Yield (wine) In viticulture, the yield is a measure of the amount of grapes or wine that is produced per unit surface of vineyard, and is therefore a type of crop yield. Two different types of yield measures are commonly used, mass of grapes per vineyard surface, or volume of wine per vineyard surface. The yield is often seen as a quality factor, with lower yields associated with wines with more concentrated flavours, and the maximum allowed yield is therefore regulated for many wine appellations. In most of Europe, yield is measured in hectoliters per hectare, i.e., by the volume