Cedar quince apple rust quandary

[WNC Bonsai]

I am in a quandary over how to handle this cedar quince apple hawthorn rust disease. Right now I have a couple small chInese quince and a couple native hawthorns. I also have J. procumbens and J. chinensis. So far all the deciduous trees ae infected with the disease and I am just trying to manage it. The junipers remain disease free and in my area I din’t know of any native junipers but there are tons of landscape junipers so maybe they are the conifer vectors. In my yard I have several native hawthorns and amelanchiers all of which have the disease so trying to keep anytning disease free seems impossible. I have been treating this year with Infuse, Daconil, and Mancozeb but from what I have read you cannot really eliminate this stuff once the tree is infected, only manage it. So I have been cutting out any swollen limbs on the quince and hawthorns as they develop. Short of that am I fighting a losing battle? Is it better to just give up on these species in my area and just plant them in the ground and grow them as landscape trees? I would especially like to hear from anyone who has actually dealt with this problem.

 

[Brian Van Fleet]

I certainly wouldn’t plant them in the ground if they’re infected. If you can replace them, I would destroy them and start over. If you have a bunch of time and money in the infected trees, I’d get on an aggressive fungicide program like we already laid out in the other threads; Cleary’s and Mancozeb have been effective for me, along with LS in the late winter.

Native junipers, ERC are notorious carriers of CA rust, so it would be just a matter of time before it’s everywhere. Shimpakus and chinensis don’t seem to get infected.

 

[parhamr]

Shimpakus and chinensis don’t seem to get infected

Huh, I hadn’t really thought of this… but it’s true in my yard, as well.

 

[wireme]

In my opinion the fact that your susceptible broad leaves are all infected means it’s airborne in your area anyways. Whether or not you keep your infected trees around will probably make little difference. Lots of air circulation and sun on the junipers can help and avoidance of wetting the foliage when spores are flying. There is a time window when the deciduous trees in the area are producing spores so that’s the time to really watch and possibly treat the junipers and cedars. Springtime the deciduous get infected by junipers and middle of summerish the junipers get infected by the decids.