Here is a grape leaf showing galls caused by aerial phyloxera.
The damage is very evident on the underside of the leaf where the bites
occurred and might be overlooked in the top view.
Aerial phyloxera do little harm and do not necessarily take up
residence in your vineyard. It is fortunate that they leave this
calling card, because it warns you that phyloxera are in the vicinity.
If you see these galls on own-rooted, non-phyloxera resistant grapevines
there is a good chance that big trouble will follow.
