Knowledgebase
Growth on New Mexico Privet #869226
Asked May 20, 2024, 11:11 AM EDT
Hi, We planted 25 New Mexico Privet in 2013, CSU bareroot stock, and they have done well until last year. Please see attached photos that I took yesterday. First noticed growths late last summer on some of the privets, not all. I didn’t take photos then and don’t recall exactly what they looked like initially. This spring several of the privets have these rusty brown colored easy to crumble growths on them. I am hoping that somebody can identify and suggest how to treat. Do I need to cut down the infested trees to save the healthy looking privets? Maybe they are all infested? We have 200 plus different trees, shrubs, flowers and don’t want this to spread. We live on Cedar Mesa outside of Cedaredge, CO at approximately 6,400’. We would appreciate any advise. Thank you!
Delta County Colorado
Expert Response
That looks like a kind of gall, maybe from a bud, on your New Mexico privet. We had another sample from the area come across the master gardener help desk earlier in the year. It looks like this report we found online: https://www.gallformers.org/gall/3972.
Unfortunately, we do not know exactly what creature causes this to happen. In some cases, galls like this are the result of eriophyid mite activity.
It can be very difficult to control insects and mites that make galls. You could try to prune out the galls, but treating with anything will be challenging because we just don't know about the timing.
Eriophyid mites are pretty specialized with their host, so I wouldn't worry about this spreading to different kinds of plants on your property.
