Knowledgebase
Severe sudden leaf disease in my flowering Hawthorne, The Dalles, OR #753785
Asked June 03, 2021, 2:40 PM EDT
Wasco County Oregon
Expert Response
This does look like a skeletonizing insect is causing damage. Several insects could be causing this damage. My guess, without looking for the insects, is that you have a pear slug problem. Pear slug is somewhat common in the Mid-Columbia region. Here is a good article about it https://pnwhandbooks.org/insect/hort/landscape/hosts-pests-landscape-plants/hawthorn-crataegus-pear-sawfly-pear-slug. I suggest looking for insects that are feeding on the leaves. If you do see something, please take a photo for me.
The Hawthorne is fairly old. I think it was foundational planting in 1950's.Several years ago, it looked like something splashed on it-the leaves over the sidewalk looked scalded and shriveled. It lost most of its berries last year. I was very pleased to see such a healthy bloom this year. Within one week it is like it burnt up. No insects seen or snsect webbing or excrement seen. No unusual bugs. It is located next to a big quince and much of the spring a large flock played in the quince most spring. I sprayed it with Neem oil and had an arborist come. He thought for sure it was an insect. But after his exam, he was not sure. I gave him a summary of a bacterial illness that causes fire blight. There is one branch that has died back. No obvious weeping bark sore, but there is a blackness to some areas of the bark. The quince is showing some signs of damage, but healthy branches have grown out.Thank you. I found no insects or insect material.
Thank you. I found no insects or insect material.
The symptoms on the hawthorn leaves are inconsistent with fire blight symptoms (1), but do display the hallmarks of insect damage, holes between leaf veins (2). Wasco County Master Gardeners will begin accepting samples in July. I suggest bringing samples to the Master Gardener plant clinic when it reopens.
(1) https://pnwhandbooks.org/plantdisease/host-disease/hawthorn-crataegus-spp-fire-blight