Need help with Juniper-Apple type of Rust on conifer

Discussion in 'Gymnosperms (incl. Conifers)' started by ashizuru, Apr 28, 2020.

  1. ashizuru

    ashizuru Active Member Maple Society 10 Years

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    Can you tell me what this is affecting one of my conifers please.
     

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  2. Frog

    Frog Rising Contributor Forums Moderator 10 Years

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    Do you have a closer shot? Speculating from a distance - I have seen both corticioid and jelly fungi look like this when the fruiting bodies are just starting to emerge. Also is it topside or underside of branch?
     
  3. ashizuru

    ashizuru Active Member Maple Society 10 Years

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    IMG-20200429-WA0006.jpg IMG-20200429-WA0004.jpg

    Here's some more shots of it it has certainly got bigger, thanks for the prompt reply.
     
    Last edited by a moderator: Apr 29, 2020
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  4. Frog

    Frog Rising Contributor Forums Moderator 10 Years

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    Looks like Juniper-Apple Rust - Gymnosporangium juniperi-virginianae. In case you are not familiar with rusts as a group - they generally move from one host to another during their life-cycle, hence the name.
    When I have seen this, it has been in terminal "sprigs" rather than along the branch, so I wonder if this is a closely related rust?

    EDIT:
    Apparently whether appearing terminal or along the branch depends on the species of host plant/tree. e.g. Gymnosporangium cornutum/clavariiforme on Juniperus communis or sabinae appears on the branch. What species is your conifer?

    A 2006* paper I consulted states there are 4 species in Britain: Gymnosporangium cornutum, G. sabinae, G. clavariiforme, G. confusum, each with specific "apple" hosts. Which of the following genera are physically closest to your conifer: Pyrus (Pear/Apple), Mespilus (Medlar), Sorbus (Ash), Cydonia(Quince)?

    *Ref: "Sorting out Gymnosporangium Species = The aecial stage." by Bert and Gill Brand and Richard Shattock
     
    Last edited: Apr 29, 2020
  5. ashizuru

    ashizuru Active Member Maple Society 10 Years

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    Hi Frog,
    is this rust treatable at all ? will the tree eventually die ? would be much appreciated if could let me know it's chances. As regards to the variety it was here when we moved in, I'll see if anybody knows , thanks for your help .
    Ashizuru.
     
  6. Frog

    Frog Rising Contributor Forums Moderator 10 Years

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    Hi @ashizuru,

    I don't have the expertise to weigh in on potential treatments or outcomes … but I look forward to learning the answer to this question from the marvellous folks in this forum who have expertise on this topic.
    - Perhaps editing the forum header to include a request for help with Juniper-Apple type of Rust might help alert others?

    One speculation to offer: Since I see containers in your photo, suggesting things could be moved, perhaps part of an approach would involve creating a greater physical separation between the "apple" and the conifer. Thus interrupting the host switch part of the lifecycle.

    Best of luck with this,
     
  7. ashizuru

    ashizuru Active Member Maple Society 10 Years

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    Thanks again for your help Frog.
     
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  8. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    Thanks, Frog. I have changed the thread name.
     
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  9. Frog

    Frog Rising Contributor Forums Moderator 10 Years

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    Pending an expert chiming in, some websurfing generates some fairly consistent-looking advice: Remove the galls (with the orange spikey telia) from the conifer and remove infected leaves from on and around the "apple." One reference says to the conifer branch 4-6 inches below the gall, then disinfect your shears.

    ...I'm mentioning it before waiting for someone with knowledge on this to comment, as it sounds like given your very recent "fruiting" of these telia/galls, there may be some timeliness involved: Removing the galls before they can send their spores back to the "apple."
     
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