1400-11 Kermes scale - Ask Extension
Thank you so much for providing much needed information on Kermes Scale and its possible treatments. I live in Longmont and have three gigantic red o...
Knowledgebase
1400-11 Kermes scale #876010
Asked July 05, 2024, 2:18 PM EDT
Thank you so much for providing much needed information on Kermes Scale and its possible treatments. I live in Longmont and have three gigantic red oaks (40-50 ft high) in the city verge in front of my home, and one block down from us is another stretch of 5 even larger red oaks (50 - 60+ ft high). Needless to say those in our neighborhood are watching our grand old friends deteriorate with great trepidation and sadness. Our city foresters will be treating these oaks systemically next spring with soil applications as described in 1400-11 (no one seems very optimistic). My question is whether trees the size our ours (40-60+ feet high) can also be treated in the fall and spring with the pyrethroid and dormant oil spray applications, respectively, as described in 1400-11? I'm just trying to picture how one can effectively spray tree canopies that are so high and wide. Thank you in advance for your consideration. Any information on KS and the accompanying blight will be greatly appreciated by many.
Boulder County Colorado
Expert Response
Good morning,
It is so hard to see a grand old tree suffering.
If these are city-controlled trees, and the city arborist has a treatment plan, then we suggest you contact the city again to discuss your concerns and request earlier treatment. Perhaps with more information you can convince them to start treatment this fall.
I found the following from K State university with further information on Kermes Scale for your information.
Kermes Oak Scale.pdf (k-state.edu)
It is so hard to see a grand old tree suffering.
If these are city-controlled trees, and the city arborist has a treatment plan, then we suggest you contact the city again to discuss your concerns and request earlier treatment. Perhaps with more information you can convince them to start treatment this fall.
I found the following from K State university with further information on Kermes Scale for your information.
Kermes Oak Scale.pdf (k-state.edu)
Hello. Thank you for your response and additional information. I will definitely share the K State information with the city forestry department and do my best to convince them to start soil treatment this fall.
My original question to Ask Extension was whether or not there is a way to treat very large red oaks (40-60+ ft high) with timed sprays in addition to the soil imidacloprid treatment. I can't imagine how one could spray trees of this size, but forestry is not my field, so I really don't know. My concern is whether soil treatment alone can effectively treat the very large red oaks.
Your information has raised a few more questions. I hope you don't mind if I ask them here.
First - I was under the impression that KS and drippy blight was potentially deadly to infested/infected oaks. I was told that the current situation might be "the beginning of the end" for the trees on my block. Some of them are doing quite poorly. But the Recommendations section of K State document states that - "Many people don't treat for Kermes scale and let natural controls build up." Does that mean that kermes scale is not necessarily a death sentence for infested/infected trees that are not treated or that do not respond to treatment?
Second - Because the scale is spreading in the oaks in our area, can or should any of the treatments be used prophylactically to prevent infections in oaks located nearby?
Thank you in advance for your help!
Regards,
slikreiser
Hi Slikreiser,
I would suggest you speak with your arborist regarding application timing on effected trees. They will make decisions on how to treat based on the life-cycle of the pests and the site needs which is important for Kermes Scale.
Thank you,
Lisa
I would suggest you speak with your arborist regarding application timing on effected trees. They will make decisions on how to treat based on the life-cycle of the pests and the site needs which is important for Kermes Scale.
Thank you,
Lisa
Thanks for your recommendation. Could you also speak to my questions about what we know (or don't know) about the effectiveness of these treatments, particularly the soil drenching treatment for very large trees), and if any of the treatments can be applied prophylactically to uninfected trees to prevent the spread.
Thank you.
Slikreiser
It's important to discuss these questions with your arborist. We don't have the cultural conditions or application information they will be using. Especially on timing, maturity of trees and effectiveness of their treatment.
I hope this helps.
I hope this helps.
