Magnolia scale in Toronto - need help

Discussion in 'Magnoliaceae' started by wayner, Aug 26, 2020.

  1. wayner

    wayner New Member

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    I have a fringe magnolia tree that is approximately 2m high. A few weeks ago I noticed that there were hundreds of wasps, hornets and other insects of various species that were swarming on the leaves and branches of this tree. I called an insect specialist and they couldn't find a nest and placed three traps. I have placed five additional wasp traps and I am now catching hundreds of yellowjackets, wasps, flies, etc per day but the issue is not going away. There are still tons of insects around the tree.

    After doing more investigation it appears that this tree likely has Magnolia scale. Professor Google tells me that this is a type of stationary insect that digests sap from the tree and secretes honeydew. The honeydew is what is attracting the wasps and other insects. Apparently the way to treat this is by spraying with horticultural oil or dormant oil which should be done in September or so when the insect does start to show some signs of hatching new eggs.

    Does it sound like my tree does have scale? If so exactly what product should I use to attack this problem? Canadian Tire has something called "Superior Liquid Insecticide Oil Spray for Dormant Trees". Should I use that? Or is there something available on Amazon or somewhere else? And how do I know when it is the right time to apply? Will I need to reapply in the spring?

    Thanks for your help!

    (First post by the way)
     
  2. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    Welcome, Wayner! I'm not going to be the one to answer this, but photos would help. You've seen photos of the "scales" in your reading, no doubt. See if you can find some and reply here with photos. Attach photos and files
     
  3. wayner

    wayner New Member

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    Here is a photo. I believe this scale is the brown bumps circled in red. Notice the wasp circled in white. I am not sure what the whitish-green flaky stuff is but it is all over the tree.

    I called this tree a fringe Magnolia. I think a star Magnolia is the more correct term when googling images.
    magnolia scale2.JPG
     
    Last edited by a moderator: Aug 26, 2020
  4. wayner

    wayner New Member

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    And here is a photo from a Michigan State website of Magnolia scale:
    [​IMG]
     
  5. wcutler

    wcutler Esteemed Contributor Forums Moderator VCBF Cherry Scout 10 Years

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    Those are lichens and they're fine. Here's a video from Penn State Extension Department, with an accompanying transcript:
    Do Lichens Cause Harm to Trees?
    Other sites say that they can point to an unhealthy tree: Is Lichen On Trees Harmful? | Independent Tree.

    Someone else will have to reply about the treatment for what definitely seem to be scales.
     
  6. Acerholic

    Acerholic Esteemed Contributor Forums Moderator VCBF Cherry Scout Maple Society

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    @wayner good evening and welcome to the forum. I think you have all the evidence that this is Magnolia scale. You have googled well !!!
    The whitish flaky stuff as you call it is Lichen and is not causing the problems with your Magnolia, but it is often a sign that a tree is under stress.
    The treatments you have been advised to use to combat the scale is correct and this is the ideal time to apply.
    There are many dormant oils on the market and I see no reason to not believe the one you have mentioned in your earlier post will not work. Akthough I have not used this brand personally. A second application maybe needed in a couple of weeks after your first.
    These insects live for one season, so an application of a systemic insecticide in the Spring is essential IMO to stop a return infection in 2021.
    Again do not worry about the Lichen.

    Hope this is of some help, but I believe you have already found the answers yourself. So well done for that research.
     

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