Lilac and Photinia Fraseri leaf problem

Asked July 9, 2020, 8:05 PM EDT

Hello and thanks in advance for considering our question. We have several lilacs that are experiencing this problem; leaves curling, leaves being eaten as leaves emerge, leaves turning color and dying. We noticed a couple of small web type cocoons on the lilac, but I wasn't able to find another and get a picture of it. Photinia doesn't seem to be getting eaten but is having the same leaf problem. Again, very much appreciate your help – thanks

Polk County Oregon

2 Responses

Hi, it looks like there might be a soil nutrient deficiency which is why the lilac leaves are showing the yellowing, (unless there was an herbicide spray or a lawn treatment which is affecting the shrubs). University of Maryland has a short information page on Nutrient Deficiency which will give you an idea of how specific deficiencies appear in plants. The key is to send a soil sample into a laboratory for analysis. Here is an OSU Extension publication of the Analytical Laboratories Serving Oregon. You can request fertilizer recommendations for specific plants which could solve the problem.

I can’t find any specific insect that targets lilac buds and leaves, though clearly there is something dining on the leaves. Keep a closer watch on the shrubs to see if the damage continues or the shrubs outgrow it.

Could your photinia have powdery mildew? This publication from OSU Extension has clear information and photos. It affects the new growth. Taking a closer look at the entire plant will help you determine whether or not this is the culprit. What about spray drift? Is the damage all on one side of the shrubs? That might indicate that there was an herbicide sprayed in the area that drifted and affected your shrubs.

Look into these options to see if they fit what you are seeing on your shrubs. Then we'll take it from there.

Anna - Thank you for taking time to answer our question. We're going to see if folks at OSU would be able to do a soil sample for us, and are keeping an eye out for bugs.
I thought I'd mention as well, we are in wine country, and our closest neighbor is a vineyard and winery across the street. I'm going to check with them and see what kind of things they spray; doesn't seem like what their spraying would be harmful to us if it was safe for the grapes. Our issue doesn't appear to be powdery mildew, but I know it's very common on the grapes and they're spraying for that many times a year.
If knowing that piece of information provides any other thoughts to you, would appreciate your advice back. Thanks again...