ID and treat a pathgen on M. sieboldii

Discussion in 'Magnoliaceae' started by waterboy, May 31, 2009.

  1. waterboy

    waterboy Member

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    North Vancouver Island
    Our M. sieboldii has developed some kind of an infection affecting is growth. It was planted 2 yrs ago and guessing it was approx 3 yrs in the pot, prior. Noticed the stem scarring last fall and originally thought it was a "buck in rut" rub damage (he turned a healthy 5 year M. grandiflora into a 6 inch stump over night!).
    This spring the sieboldii budded out with leaf and flower buds uniformly throughout the plant but in the last 2 weeks one of the main stems exhibiting the most serious scarring/damage has wilted and browned the both leaf and flower buds (some very small shoots appear to be emerging unscathed thou). A secondary stem off an adjacent main stem is also showing same wilt and as well has to a lesser degree the same stem damage.
    The rest of the plant appears to have good vigor and healthy flower buds. The injury/infection of the stem on closer inspection does not match rub damage and appears to be a dry canker or something within the stem drying the bark out and splitting vertically, partially girdling stem.
    At present contemplating pruning the infected stems off and thinking perhaps get onto a winter dormancy spray program. Any ID on the pathogen and other treatment options?


  2. Ron B

    Ron B Paragon of Plants 10 Years

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    WA USA (Z8)
    Probably Pseudomonas syringae. Search "magnolia bacterial blight".

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