What is this disease......it looks like phylloxera.

Asked May 8, 2020, 3:20 PM EDT

I have just over 100 pinot noir vines that were planted 3 years ago. They are PN Pommard/ 101-14 grafted vines. Last year I saw this disease and assumed it was controllable with Sulphur but that apparently didn’t work. This year it is back on a few vines. Can u identify it and tell me how to get rid of it? Please.

Washington County Oregon

2 Responses

Thank you for the images. The "bubbling"of the lavs is not pylloxera. It is caused by very tiny grape erineum mites,

The mite feeding causes the upper leaf surface to be blistered, whereas the lower leaf surface of the blister appears hairy and white, resembling fungal growth. The white "fuzz" is actually enlarged leaf hairs, the enlargement caused by the mites' feeding. Later in the season, the white will change to pale brown then, finally, a dark brown.

These mites are far smaller than the spider mites you may be familiar with; they are microscopic.

Fortunately, erineum mites don't affect the vine's health nor fruit set and development.

Management for home use is as follow:
- Dormant-season oils and insecticides which used for other pests in the fall; also
- Sulfur applications which have been used for powdery mildew.

It's challenging to eradicate grape erineum mites, so it's a good thing they don't negatively affect the vine nor fruit production..

Thank you, I am happy to know that my vines and grapes will not be severely harmed.