Auxerrois and Periderm Formation

We have been having another week of temperatures in the 90s the second heat wave of this summer. It began on Friday, August 14 and has been non-stop. We did go into the vineyard to do the count of plant affected with the Grape Leaf Problem and saw that our Auxerrois grapes are swelling. They are ahead of our Chenin Blanc grapes and are ripening as we had expected, sooner than the Chenin.
Not only that, the periderm on the shoot is beginning to form, a sign that the plant is getting ready for dormancy. The periderm formation begins at the base of the shoot, where it is connected to older wood and then continues to the growing tip. The Auxerrois and the Chardonnay are forming periderm, but the Chenin Blanc is not. This is interesting phenological development for us to observe.