Is this sun damage or pesticide damage.

Asked August 14, 2019, 11:03 AM EDT

Waiting for Response. 8/20/19.
Client brought in a few branches off of her Harry Lauder Walking Stick Tree. The leaves are turning brown and shriveling up. She has been spraying for Japanese Beetles all summer, which makes me think pesticide damage. Also, with the heat and no rain could it be from that? The tree is 15 years old. On some of the leaves you can see where the beetles were having lunch. I did give her information on the Japanese Beetle. But she would like to save her tree. I have attached a picture of the whole tree and two that I took of the branches she brought in. Thank you!

Gladwin County Michigan trees and shrubs

3 Responses

I have to agree that it could be herbicide damage. It would be helpful to know what was sprayed on the tree, and what the weather conditions were when the tree was sprayed. I am attaching an article about insecticidal soap, because that is often what gardeners turn to without realizing the damage that can come from using it when it is hot and sunny.
I hope this is helpful.

I spoke to the homeowner. She said that her husband used Seven and sprayed twice a month. Sometimes only once. What can she do to save the tree? Fertilizer and plenty of water? What would be the best fertilizer? I thank you for your time and advice.

Sevin (carbaryl) can damage leaves in very hot humid weather, though more rarely than with insecticidal soap. Make sure the tree gets watered if there are droughty periods, Mulching can improve moisture and temperature consistency for the roots. Fertilizing stressed trees is not a good idea, however. I would also ask the client to carefully check the limb suffering the worst foliar damage. She should be looking for any irregularities in the bark, because this shrub is susceptible to a fungal blight that can cause limb death, and ultimately, plant death. I will attach an article on this disease so they know what to be looking for.