Leaf botrytis has developed in vines that were damaged by earlier hail and wind. This is common in seasons where McLaren Vale has windy and wet weather in spring.
Further rain increases leaf botrytis infections while dry conditions will heal it up.
Leaf botrytis is very easy to monitor for but because it is obvious many growers worry about it. The good news is unless the leaf botrytis spreads onto the stems or inflorescence vines recover quickly with warm and dry weather (pictured recovering below in spring 2008).