Juniper Hawthorn Rust - Ask Extension
Our house is on 2 acres along SH 115 (Pinon Juniper Pine system) -- We have several cedars embedded in stands of gambrel oak. The cedars have Junipe...
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Juniper Hawthorn Rust #640609
Asked May 25, 2020, 11:30 AM EDT
Our house is on 2 acres along SH 115 (Pinon Juniper Pine system) -- We have several cedars embedded in stands of gambrel oak. The cedars have Juniper Rust at the Teliohorn stage. There are no second host trees nearby. Question - Cedars are not good to have around due to fire proclivity. Should I just clear them out or should I treat them for the Rust? If treatment is an option, should i wait for the Teliohorn stage to pass?
El Paso County Colorado
Expert Response
Hello,
The junipers will probably survive the rust if you want to keep them, since the rust does more harm on the alternate host. There has to be an alternate host somewhere in the vicinity (several hundred yards) for the junipers to be symptomatic (this can be an apple, hawthorn, mountain ash, crabapple)- even if not on your property).
Chemical control usually is not necessary on juniper. However, if fungicide control is desired, application to juniper would occur from July through September at two-week intervals. Mostly, it's the alternate host plant that is treated, but you'd have to find it, first (and then it would have to be on your property), and the window for treatment is in the spring at blossom time.
You could take out the junipers for fire danger, but gambel oak are also a flammable species, so it probably wouldn't gain you that much. You may not really need to do much of
anything.
For more information:
https://static.colostate.edu/client-files/csfs/pdfs/juniper_hawthorn.pdf
The junipers will probably survive the rust if you want to keep them, since the rust does more harm on the alternate host. There has to be an alternate host somewhere in the vicinity (several hundred yards) for the junipers to be symptomatic (this can be an apple, hawthorn, mountain ash, crabapple)- even if not on your property).
Chemical control usually is not necessary on juniper. However, if fungicide control is desired, application to juniper would occur from July through September at two-week intervals. Mostly, it's the alternate host plant that is treated, but you'd have to find it, first (and then it would have to be on your property), and the window for treatment is in the spring at blossom time.
You could take out the junipers for fire danger, but gambel oak are also a flammable species, so it probably wouldn't gain you that much. You may not really need to do much of
anything.
For more information:
https://static.colostate.edu/client-files/csfs/pdfs/juniper_hawthorn.pdf
