Knowledgebase
management of wild plum thicket and apple tree extensive galls #873525
Asked June 17, 2024, 6:37 PM EDT
Bought a one acre plus property last August and have discovered a 100 x 150 foot area of wild plum thicket and nearby large old apple tree in the back acreage that have heavy leaf gall infestations. Wild plums starting to grow down a small hill seem to have the disease too 150 feet away. I'm going to cut everything down and burn it. (1) Do I need to get rid of the soil as I am reading in places, and if so how deep? (2) Will burning spread the infection? (3) Also planted a number of fruit trees before I discovered the galls this spring - including some apple trees 50-100 feet away from the infested thicket on the top of the hill, and pear, plum, peach 200 feet away down the hill. Have read the mites are tree-species specific, so do I have to worry about the apple trees on top of the hill, and what about the other fruit varietals? Thank you!
Lake County Illinois
Expert Response
Do you have pictures of the leaf galls? I'll need to be able to identify/verify the organism causing the galls before I can provide any advice. If you have pictures representing the galls seen on each plant species on which they are occurring, that would be helpful.
Thank you.
Talon Becker
Illinois Extension
It would be a lot faster and easier....
Sent: Tuesday, June 18, 2024 7:32 AM
To: Small, Stephen [BSD] <<personal data hidden>>
Subject: [EXTERNAL] Re: management of wild plum thicket and apple tree extensive galls (#0143443)
Regards,
Talon Becker
Illinois Extension
Sent: Tuesday, June 18, 2024 9:27 AM
To: Small, Stephen [BSD] <<personal data hidden>>
Subject: [EXTERNAL] Re: management of wild plum thicket and apple tree extensive galls (#0143443)
I've heard back from my colleagues and have some information to share.
It looks like these galls may be caused by two different species of eriophyid mite. The galls on the maple appear to be maple bladder gall, reported to be caused by Vasates quadripedes. And on the plum, it looks like plum finger gall, reported to be caused by Eriophyes emarginatae.
Some online resources suggested pruning and burning may help control the populations of these mites, but my colleagues that work in tree fruit production said it would likely not be possible to completely control these mites, particularly if you are in a wooded area. But not to worry, because they also said these galls do not cause negative health effects for the host tree. Cultivated varieties of fruit trees can sometimes be colonized by these or similar mites, but it is generally not extensive, often don't happen every year, and should not compromise the long-term health of the tree. One colleague said she had similar gall-forming mites on one of her trees in her back yard over a decade ago, but she hasn't seen it again since.
Now, although the eriophyid mites are generally not harmful to fruit trees, the spider mite can cause some issues. However, these are not gall-forming mites. They cause more of a stippling or speckling of leaves with their feeding. I didn't see any signs of damage from this mite in your photos, but I've included a couple images supplied by one of my colleagues that shows what spider mite damage looks like on the top and undersides of leaves.
I hope this helps. Let me know if you have any follow-up questions.
Regards,
Talon Becker
Illinois Extension
