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sluice

what is this?

sluice
11 years ago

Saw a Juniperus osteosperma a few days ago with some of these things growing on it. Any ideas? Thanks.

J. osteosperma

J. osteosperma

J. osteosperma

Comments (14)

  • jimbobfeeny
    11 years ago

    Looks like a witch's broom - That's where most funky conifer selections originate. Try grafting it onto a rootstock and see what it turns into!

  • kbguess
    11 years ago

    mistletoe ?

    Keith

  • treebarb Z5 Denver
    11 years ago

    kbguess,

    Mistletoe was my first thought, too. I tried finding pics, but they don't look quite like that. The growth seems too different to be a broom. I hope it's not mistletoe.

    Barb

  • sluice
    Original Author
    11 years ago

    Hmm, maybe it is a broom, or some sort of disease.

    Here are a couple of pics of juniper mistletoe from a J. monosperma in New Mexico, which looks like Phoradendron juniperinum.

    Phoradendron juniperinum (?)

    Phoradendron juniperinum (?)

    I had thought about trying to root that small rosette, and even brought one home with me.

  • greenhaven
    11 years ago

    Well of COURSE you brought it home, lol! It will be interesting to see how that comes out.

  • ishcountrygal
    11 years ago

    I've enjoyed reading some of the threads in this forum, as I'm a fan of conifers.

    I was curious about the cute little growth on the juniper, so I went to Google. Here's what I found:

    It appears to be a gall, the home of the larvae of juniper tip midge (Oligotrophus betheli).

    You can look for mining and exit holes "found at the junction between living and dead tissue or at the base of the swollen portion". This is from the Pacific Northwest Insect Management Handbook: http://insects.ippc.orst.edu/pnw/insects?16LAND10.dat

    This midge lays its eggs in Juniperus occidentalis, J. scopulorum, J. virginiana, but is especially common on J. osteosperma in Colorado and Utah according to the book 'Forest Entomology' by William Ciesla.

    Although from western N America, the juniper tip midge is also an expat in Serbia; it was first identified there in 2007 on J. virginiana.

    The number of rosettes in the gall is between 5 and 20. A photo of galls is on p.59 in www.aspensite.org/FTP/Colorado_insects_Feed_Trees.pDf

    And finally, people who study galls are called cecidologists!

    BTW Sluice, nice pics. Your third photo looks like that of a beautiful christmas tree ornament.

  • ishcountrygal
    11 years ago

    Whoops! Didn't mean to send this twice.

  • sluice
    Original Author
    11 years ago

    Thanks IshCountryGal!

    Tomorrow I'll inspect it for mining and exit holes.

  • sluice
    Original Author
    11 years ago

    So here is the gall, there were 10 small rosettes.

    After pulling apart each rosette, I noticed the juniper tip midge larvae were still in the gall.

    Oligotrophus betheli larva in Juniperus osteosperma gall rosette

    A close up of the juniper tip midge larva

  • greenhaven
    11 years ago

    What amazing photos! It makes me so happy when folks are curious enough to really explore. What a great learning experience, thanks for sharing!

  • sluice
    Original Author
    11 years ago

    Thanks greenhaven!

    To complete the story, this is Glenwood Springs, CO where the gall was found. That's the Roaring Fork river coming down the valley, from Mt. Sopris in the background.
    A nice mix of J. osteosperma, J. scopulorum, P. menziesii and P. edulis along this canyon.

  • ishcountrygal
    11 years ago

    Really nice work sluice! That's a mighty little midge to provoke that response from its host.

    I envy you the beautiful blue sky in the last photo. We're in the midst of "June gloom" here in the pacific NW.

    -m

  • pineresin
    11 years ago

    Yep, Juniper gall midge. I remember seeing them on J. osteosperma in the White Mts in California. This species seems particularly prone to them, though I've read they occur on some other junipers too.

    Resin

  • Colin Purrington
    3 years ago

    Walshoymia sp.

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