I've heard that a number of Southern Hemisphere species are quite a bit more susceptible to root rots and other fungal blights such as cercospora, etc...Recently a twelve foot tall Athrotaxis Laxifolia at STrybing Arboretum succumbed to disease (a huge loss as it took years for it to get that high!), most likely phytophthora. Any input on this? Is there increased vulnerability among many southern hemisphere species to northern hemisphere fungal diseases, and why? I'm guessing it's because they simply evolved on the other side of the equator and have not evolved with the northern diseases and thus have little to no resistance to them. Any input on this? Athrotaxis has become one of my favorite species and I would love to know what the risks/things to watch out for in growing them. Here is a drawing I just completed of one of the species...
I'd agree with that prognosis. In Britain at least though, they don't appear to be markedly more disease-prone than many other Cupressaceae; survival is generally fairly good. Try as far as possible to grow them in well-drained soils that are less conducive to fungal growth.
The horticulturally important root rots are caused by water molds rather than fungi. There is a convention of referring to these as fungi but they are more like brown algae than fungi. The carcass of the Strybing specimen should have been tested for infestation by placing samples on agar before it was concluded it was lost to any particular pathogens. According to Jacobson, North American Landscape Trees (1996, Ten Speed, Berkeley) an Athrotaxis laxifolia planted in Port Coquitlam before or during the 1930s was 33' tall by 1994. This height measurement would have been gotten from one of the specimens at this facility: http://www.rhcs.org/index.html
Yeah, I should've said water molds, oomycota, etc. but... one question about them...you say they're more related to brown algae? I've been trying to read up on these for a while, I've read that they "swim" - how true is this? What is a standard method for detecting pythium, phtyophthora, etc. and do you know the name of any potential non-toxic bio-control methods (namely bacteria) that are effective against them? Thanks for your time.
There lies the problem - very few people have the funding, or access to the facilities, to carry this out.
"specimen mentioned was at a public facility"... ...that's enormously short on funding and was, in fact, considering charging admission for the first time in it's 80+ years until the level of public outcry against doing so made the change to "suggested donation" instead. But any info on potential biological control agents for the water molds? Someone once told me the name of one but I have since forgot. IT's made by a company based in fresno...any info?