I have an older Chamaecyparis, I think lawsoniana, that has just been diagnosed with root rot, presumed to be Phytophthora lateralis. I believe the tree is doomed. I need to select a rapidly growing replacement tree, and am keen to avoid planting anything that may be susceptible to the fungus which I expect will remain in the soil. What trees are resistant? or, if the list is shorter, what is susceptible ? Also I have a densely planted shade garden near the sick tree, including woody shrubs and subshrubs like rhododendrons and camellias, some of which were acquired from you-know-which Californian nursery several years ago... they all look completely healthy.. but a) is the P. ramosum capable of killing a Chamaecyparis? and b) if the root rot in my chamaecyparis is in fact P. lateralis, can it affect rhodos/camellias? (..ie do I have an incipient plague in my dingly dell??..) Help!
Everything I've read says that Phytophthora lateralis only kills Chamaecyparis lawsoniana (it is resisted by other Chamaecyparis species). Lawson's is also susceptible to at least some other Phytophthora species, though I don't know if it is susceptible to P. ramorum or not. If you want something fast-growing, try Grand Fir, Douglas-fir, or Western Hemlock. Bear in mind that they'll all get huge eventually!
Thanks Michael! Does anyone else know whether Phytophthera lateralis attacks broadleaf evergreens? I am considering eucalyptus, pauwlonia, magnolia as possible replacements for the poor Chamaecyparis with root rot. MdeHaan
Sinclair and Lyons book "Diseases of trees and shrubs" lists P. lateralis as being found to infect some rhododendrons in Ohio.
Did a lab grow samples on agar and determine your tree died from that specific water mold? Others also infect the same species and kill it in western Washington, according to an authority on the subject.
Thanks Jimmyq - I shall consult your refence further. RonB - No, my tree's diagnosis is not laboratory-confirmed. The arborist told me thyis mold is the one that commonly affects Lawson's cypress in this region.
Not a very precise diagnosis. Really need to put tissue samples on agar to know what is present. You may be asking about an organism that is not even involved.
I don't know when my tree was planted. it is approx 15meters high, and the diameter of the trunk a meter above ground level is about one meter. Ron's point re: diagnosis was wwell made. I have decided to wait and see what happens - I know of a man with "pancreatic cancer" who is alive ten years later - perhaps my tree will be too.... (perhaps not). I shall not cut it down til it is clearly dying. Ron - at least in Victoria I am told that a laboratory diagnosis of root rot affecting a home gardener's tree is not easy to come by. Thanks everyone and happy holidays.
There are several fungicides which will help control root rot, if your cypress tree is still worth saving. http://www.growercentral.com/index....ion=basicSearch&CFID=2428820&CFTOKEN=46115287 [That link didn't work right - product search for Aliette, Subdue Maxx, and or Ridomil] Ridomil has worked well in the past for me on Lawson Cypress for root rot. But I've never treated a tree as large as yours. Subdue Maxx is another root rot fungicide. Although these fungicides are registered more for nursery stock doesn't mean they wont help your tree. Copper spray on the foliage is also helpful in protecting aerial parts of the tree from infection by Phytophthora (as quoted from the link below), and deep root fertilizing could'nt hurt either in keeping your tree stronger and healthy. http://www.ipm.ucdavis.edu/PMG/r280100311.html#MANAGEMENT But of coarse any IPM measure should be a first choice. Just a tree sprayers suggestion, cure it don't let it die! I use the Ministry of Environment in Abbotsford to do lab tests for me, there $15.00 each. They may have an extension in Victoria, or you could courier over a sample of the root. I hope your tree lives a long time,, Jim.
http://lyons.ipm.ucdavis.edu:16080/cgi-bin/htsearch 1 more thing, according to this link it looks like many plants get Phytophthora Root Rot.