Names of diseases caused by Heterobasidion spp.

Forest Pathology Fora Root Diseases Annosus Root Disease Names of diseases caused by Heterobasidion spp.


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    Jim Worrall

    I suggest that the diseases caused by the members of the H. annosum complex are different enough and important enough that they deserve names of their own, rather than being lumped under one disease name. As a side benefit, this would allow us to drop the latin from the disease name.

    Let’s review the disease names that have been used in North America. This was “annosus root rot/disease” when the pathogen was called Fomes annosus. When the name Heterobasidion annosum came into common use, some thought it should change to “annosum root disease”. When multiple species were carved out of H. annosum sensu lato, many gave up that approach and used the genus, or “Heterobasidion root disease”. All three of these disease names are now in active use! And how long will it be until a new genus is used for these species?

    Obviously, this is confusing to nonspecialists. French-speaking parts of North America missed all this because they use the great name “maladie du rond”, or circle disease, referring to disease centers.

    For better or for worse (mostly for worse), many diseases are named in part after pathogens. But latin in a disease name has several disadvantages:

    1. Such names are hard for nonspecialists, like students, foresters, and arborists, to learn and remember.
    2. The latin words carry no meaning to most of us; even for those who know the latin meaning, they generally convey little or no useful information.
    3. The practice feeds confusion about a disease and pathogen being the same thing.
    4. As noted above, such names lead to an awkward situation when the pathogen name changes, leading some to change disease names.

    A good disease name should be memorable and highlight some important feature of the disease, like the name in French. None of the names currently used in English do this. Moreover, it may be time to recognize these as distinct diseases.


    I am interested to see where this goes as I currently think of all three disease names as correct too, no matter the new species, yet, at the same, time agree that is pretty confusing regarding relaying information to non-specialists. “HRD” is another one that I have used too as an acronym. I agree separate informative disease names would be good.

    Dave Shaw

    I agree with you Jim, this needs dealt with. too much confusion by foresters and managers when the name is changed all the time because of scientific name changes. However, I will admit, it is hard to remember the difference between red brown root and butt rot and brown root and butt rot etc. So we need names that clearly link people to the disease. Laminated root rot is a good example, everybody know it….although the older foresters call is poria…ha.

    Perhaps once you get a good amount of feedback a proposal with specific names could be made to the root disease committee at WIFDWC.

    Good on ya

    John Guyon

    Agree with all the reasoning, but haven’t heard any suggestions as yet. The primary annosum we deal with in the fir variety, and for this I suggest: Jacobi’s hollow butt, in honor of my mentor, Bill Jacobi. Or alternatively, The Baker parachute disease, in honor of Fred’s assertion that if dropped by parachute anywhere in fir forests, he could find this disease in 15 minutes.

    But seriously, how about fir hollow root disease?


    I am working on getting a southern pines project together so dealing in part with “p-type” H. irregulare. Sometimes the disease is referred to as “HRD” of southern pines, maybe “SRD of southern pines” would be better since it is usually found on sandy sites, ie, “Sandy-site root disease of southern pines”. I think that would be easy to remember. Or “Otrosina’s southern pine root disease”.

    Jim Worrall

    I was thinking we should first deal with whether we should do this before muddying the waters with discussing specific names, but didn’t actually expect that to happen. So let the name games begin!

    First let me say thank you to John for a good belly laugh at his names, followed by chuckles later as they came back to me. My idea for the disease caused by H. occidentale was “western root disease”. I think Otrosina and Garbelotto made a good choice of a specific epithet there, because ‘occidentale’ indicates that it is the disease that is restricted to the western portion of the continent. This is an important feature that is worth noting in the disease name. That said, “hollow root disease” is also good. It certainly is a memorable feature in fir stumps (although I vaguely recall, and probably have in my files, an old paper in a southeastern forestry publication with a title something like “Fomes annosus is hazardous to your health”, because the pine stumps and roots are hollowed out, causing a tripping hazard). I’m not sure I would put ‘fir’ in the disease name, since in some areas it is most notable on hemlock, or Douglas-fir, or spruce.

    As for the disease caused by H. irregulare, it is important in the West also, and has become more important in the Midwest. It also occurs in the Northeast, southern Canada, and Mexico. So unless it causes a distinctly different disease in southern pines than in the other areas, I’m not sure it is good to focus on southern pines for the disease name. For it I thought of “pine stump disease”, but would not be surprised if a better name could be found. Maybe a translation of “maladie du rond”?

    Martin MacKenzie

    I would like to express the minority opinion. There is nothing wrong with Latin. Common names are just what is commonly used, and they come into and go out of fashion. But Latin is more stable, not permanent but more stable. I use for example the “fir variety of Heterobasidion etc and if we change the Genus I’ll then change the Latin.

    Jim Worrall

    Thanks for the input Martin. That’s a valid opinion. I agree there is nothing wrong with latin for scientific names of organisms, but outlined 4 reasons why it is not good in disease names. It sounds like you are thinking of common names of pathogens, when you mention “common names”, like “fir variety of Heterobasidion”. As you know that’s a pathogen, not a disease. Disease names of course are not common names of pathogens.


    I guess getting away from common names was why Linnaeus set up the latin binomials. My vote would be to keep the Genus name as a common name. People have managed with cumbersome plant names at their local plant nursery, and I would expect them to do so with fungal names.

    Alternately, a name could be crafted from the Latin Hetero: other/different/not normal and basidion: club shaped, but it doesn’t exactly roll off the tongue.


    Maybe I’m living on the wrong side of the plains to offer an opinion, but I think the best common name for now is Heterobasidion Root Disease, HRD. I’ve been advocating for that for several years now, because I thought that was the right answer. I expect the species associated with the various hosts and locations will continue to change… names may change, perhaps species will be added. It will continue to be confusing. But bumping the name up to the genus level gives some level of stability. I am hoping the genus name does not change again any time soon. On the landscape, without a conk or a PCR or some other conclusive evidence, it is difficult to distinguish the variants of disease caused by Heterobasidion, the main distinction being host. Symptoms often vary by region or subregion… HRD in an unmanaged shortleaf pine plantation in southern Illinois doesn’t necessarily have the same “expanding pocket” pattern that HRD in a untimely-thinned red pine plantation in Michigan has. So a symptom-based common name is also confusing. And with H. irregulare being present in both east and west, I don’t think it is going to be any less confusing. So for me, the easiest solution is to just use the broader term HRD to include root disease caused by any Heterobasidion on conifers, and then refine which one it might be by naming the host. I think we’ve almost gotten our northeastern population of pathologists and silviculturists to use HRD most of the time, though we know what people are talking about when they use fomes/annosum/annosus root rot/disease. We just got the new eastern FIDL (Heterobasidion Root Disease in Eastern Conifers) completed with the name HRD. I know it’s not perfect, but I’m of the opinion it is better than many of the other options. I’d hate to see it changed now.

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