Yellow spots on grape leaves

Grape    PA

My husband brought home some grape plants yesterday that he found in the store. I had mentioned growing some grapes to him a few weeks back so when he saw them he decided just to buy them. One of the plants he brought home has some yellow spots on its leaves. I have taken a picture of this. Is it something I should be worried about? I don't want to put a diseased plant out into my garden. The plants seem quite pot bound and really need planting so perhaps this is just some kind of deficiency? I would appreciate help identifying the cause of this.

Posted by: Marsha Anderson (5 points) Marsha Anderson
Posted: May 6, 2013


Have you looked on the corresponding underside of the leaves? This could be the early stages of downy mildew though it seems a little early for that. If there are no obvious insect or disease markings and just the discoloration, I would say to plant them. Plants really get abused at stores and you never know what kind of mechanical damage or nutrient deficiencies are going on. It's worth it to just plant and keep a close on it.

Posted by: Kathryn Fiedler (72 points) Kathryn Fiedler
Posted: May 7, 2013

Marsha Anderson commented,
There doesn't seem to be anything on the under sides. I suspect it is a deficiency of some kind but good to check. Thanks for your help
over 7 years ago.

You may want to submit specimens to Penn State's Plant Disease Clinic http://bit.ly/10r7hLu There's no charge, and you should get a definitive answer about whether the spots on your grapes result from disease, deficiency, or some sort of environmental damage--as well as what to do about it (if anything). If it is a disease, it could spread to the other plants.

I've used the corresponding diagnostic service here in New Hampshire several times, with great analysis & results.

Posted by: Peg Boyles (3 points) Peg Boyles
Posted: May 8, 2013

Unless there is a gray fuzz in these spots on the underside of the leaves (sign of downy mildew), I would not be too concerned. The spots don't have very sharply defined edges, and I suspect this may be just normal 'wear and tear' from the garden center. If the young leaves come out and look healthy, things should turn out fine.

Posted by: Charlie B. (2 points) Charlie B.
Posted: May 8, 2013

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