Black Walnut dying?

Question: Hello,  My black walnut started dropping leaves. At first I thought it was the squirrels but the volume has significantly increased and now the tree doesn't look good.  I'm wondering if it's dying?  Thanks, Aimèe

responder: Neil Bell  Replied June 08, 2023, 10:43 AM EDT
response: The photo of the foliage on the ground shows that this is actually an English Walnut. Also the leaves appear to be falling whole, or nearly so. There is some evidence on the leaves of Walnut Blister Mite, which is pretty common, but this little pest would not cause whole-leaf loss. The fungal disease anthracnose could cause defoliation, but there is no sign of the spotting or yellowing of leaves that this disease can cause. I'm unaware of other pests that would simply cut off leaves for no reason, as they have basically fallen off without obvious symptoms of why. I'm not sure why squirrels would do this, either. It's possible that it is some physiological response of the tree to it's environment, possibly the cool, wet, weather in April, followed by some significant heat in May. Also, any disruption of the root zone of the tree could conceivably cause this sort of symptom, such as digging around the tree. Herbicide use on the lawn near the tree may also cause defoliation in some cases. If you can post a photo or two of the whole tree in daylight, that might help see any patterns of defoliation on the tree itself and provide more clarity

responder: The Question Asker Replied June 08, 2023, 8:08 PM EDT
response: Hi Neil, Here are pictures of the tree that I just took.  I also noticed that now the leaves have black spots and some yellow spots. These are new. They weren’t there last week and it’s the leaves on the tree not the ones on the ground.The last picture is hard to see because I’m aiming up so the sky makes it look very dark but you’ll see that branch now looks dead and is clear of leaves.I have 2 English Walnuts the 2nd is about 75’ away but it’s now starting to drop leaves as well.Hope these pictures help.  I appreciate the information you provided already. Thanks, Aimèe From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask ExtensionSent: Thursday, June 8, 2023 7:43 AMTo: AIMEE ORTIZ <<personal data hidden>>Subject: Re: Black Walnut dying? (#0103452)

responder: Neil Bell  Replied June 14, 2023, 11:08 AM EDT
response: The photo of the canopy appears to show some dieback of a limb (maybe more than one, but I can't tell). That might be because of bacterial canker, or possibly winter injury, or some combination of those. That said, I can't tell from the photos the reasons why the leaves would fall off as they did. The close-up photos of the two leaves show mite activity on one and some scarring on the other, but that would not caused defoliation. Are the areas of dieback new on the tree this year?

responder: The Question Asker Replied June 14, 2023, 11:55 AM EDT
response: Yes, the die back and the significant dropping of leaves is all new.  If this was happening after the ice storm of Feb 2021, I wouldn’t be too surprised.  That was a very harsh winter. I can’t think of any real reason for this to happen now.  It’s early in the growing season too, so also surprising to me.Thanks so much for your help.  I’ll keep an eye out and see what happens. From: ask=<personal data hidden> <ask=<personal data hidden>> On Behalf Of Ask ExtensionSent: Wednesday, June 14, 2023 8:08 AMTo: AIMEE ORTIZ <<personal data hidden>>Subject: Re: Black Walnut dying? (#0103452)