It scarcely seems necessary to remind anyone that now is the time to do anything but harvest grapes. Nevertheless there are reports that downy is prowling through the region. It may well have visited your place, particularly your red varieties.
It is worth inspecting your vineyard for signs of oils spots. This may be more important if copper or mancozeb sprays have not been applied during the season. If downy mildew is present growers should apply 5 x Metalaxyl sprays back-to-back in the next week.
No controls are necessary at this stage, but with the possibility of more rain and dewy mornings sporulation may be triggered leading to canopy damage and leaf loss. Note: This may also lead to less carbohydrates being stored in the vine for dormancy and causing poor vigour next season.
So, get out your flagging tape and get on your bikes. Flag any oil spots then regularly check their progress to see if spread is occurring. If growers have an infection it’s important to do whatever is practical to help air flow and lower moisture levels, eg slash inter-row and review irrigation schedules.