Cane Girdler on my Therese Bugnet

Good morning everyone!

This year, the worst thing I've discovered on/in regards to my roses is cane girdler on my Therese Bugnet.

You know those lovely photos of my younger specimen I've shared previously?

Gone. She only has two or three canes left.

Every other cane ended up with the telltale signs: bulging of the cane, weird autumn colours followed by gradual death of everything above the bulge, and finally, canes that snap right off all too easily at the swollen points.

I'm naturally upset as I've never had this particular and troublesome pest before.

I've removed all the effected canes that I can locate and cut several inches below the bulge.

Researching old posts, I discovered one from AnneCeceliaZ5MI (IIRC) regarding this same issue, and I believe she may be the poster that stated she had to give up the variety due to the severity of the problem.

My question and speculation regards the source or origin of this pest. I've grown Therese Bugnet for over 20 years now between two gardens and had never had the problem before; could the pest have come in on, say, infected roses from Canada? I'll refrain from naming "anyone" here although there aren't many to guess from. The reason I had this thought was that I never had the pest problem until *this* year when I planted one of these new roses (a 'Flaming Peace', actually) in the same bed area.

Moving forward, I know that rugosas do not tolerate being sprayed with chemicals very well, but I'd like to try and eliminate this problem as early on as possible because I do not want to give up one of my most favoured roses. Ought I give a dose to Therese to try and prevent additional infestations moving forward? Dormant oil late autumn and spring to smother eggs instead? Could the pest have finally migrated into my region after all these years? I'm rather frustrated!

I'll add pictures tomorrow as I can. I'm in the middle of my workweek and have limited time on account of twelve hour shifts.

Any advice/further speculation and idea tossing is most welcome!


Comments (7)

  • strawchicago z5
    29 days ago
    last modified: 29 days ago

    I got cane-borers on Fast growing & constant blooming Firefighter in its 2rd & 3rd year. I used glue to seal the bore holes, but that didn't help. Then Firefighter died through a dry spring as 3rd-year-own-root. When I dug it up, I found trees' roots invading that area, stealing alkaline minerals (esp. calcium).

    In contrast, Big Purple next to my limestone patio never have that problem and lived for 8 years, despite being under the roof-overhang that blocked 80% of rain.

    After Firefigher got infected with cane-borers back in 2015 (the only rose among my 147 varieties). I put lots of calcium (gypsum) to break up my rock hard clay. I also top roses with pelletized lime during heavy rain, and no more cane-borers in my garden. Rain leaches out calcium big time, found 1/8 cup of whitish calcium oozing out from the bottom of each pot after week-long rain. Calcium hardens plant tissue.

    One time I planted bok-choy vegetable next to my limestone patio and it was INEDIBLE, so tough and fibrous. So I put 6 cups of pelletized lime in the planting hole of each tomato, and zero cracked tomatoes this year, and no tomato worms for the past 20 years of putting calcium in the planting hole & zero chemical fertilizer.

    I use pelletized lime with 86% calcium carbonate since my clay is exceedingly high in magnesium, so I stay away from Garden lime (22% calcium and 12% magnesium). Below is Firefighter as 1st year own-root, it's a fasting growing & constant blooming so it used lots of calcium & potassium (got up to 3 feet in its first year as own-root):

  • Mischievous Magpie (CO 5b)
    29 days ago

    Steven, that's tragic and I'm so sorry. I don't have any experience or advice for you, I'm just really sorry you're going through that with such a beloved plant. The internet says:

    So, this could maybe be too radical, but do you think TB would tolerate having a total haircut, to eliminate the eggs and bugs in the canes? And, if any, what the cause of possible plant stress could be? I know you've said you don't give it supplemental water, but maybe a haircut and a big dose of water for the next year would help it regrow and not give off any stress signals? If they're overwintering IN the stem, I'm not sure an oil would work at this point. Maybe next spring though?

  • MiGreenThumb (Z5b S.Michigan/Sunset 41) Elevation: 1,029 feet
    Original Author
    25 days ago

    Mischievous, right about it already being infected.
    That's why I'm removing all affected canes and THEN use chemical intervention on the plant. I'm anticipating using a systemic versus topical.

    Here's my poor Therese. Not much left of her now...


  • rosecanadian
    24 days ago

    Awwww, Steven...what a shame!!! I've been so impressed by your TB bush!!! What a terrible, terrible shame. :( :( :(

    MiGreenThumb (Z5b S.Michigan/Sunset 41) Elevation: 1,029 feet thanked rosecanadian
  • rosesmi5a
    24 days ago

    Steven, here in Michigan the wild black raspberry support a huge population of the raspberry cane borer. I wonder if this is what you have. This pest also loves rugosas, but seems to leave the native roses and hybrid teas alone.

    I have only two rugosas left -- and every spring I have to find the injured canes, cut them off about 2" below the gall, and burn the cuttings. The pest seems to prefer 2-3 year old canes.

    Here's what MSU says:

    FYI: MSU put in a huge planting of rugosas in a median strip -- and pulled them all out within 3 years due to cane borers.

    MiGreenThumb (Z5b S.Michigan/Sunset 41) Elevation: 1,029 feet thanked rosesmi5a
  • MiGreenThumb (Z5b S.Michigan/Sunset 41) Elevation: 1,029 feet
    Original Author
    24 days ago

    rosesmi5a, thank you. Those seem to be exactly the pest I'm experiencing. The images of tip die-back are spot-on to what I did observe early in the season.

    There is quite a high population of black raspberries around, but I'm wondering why they took so long to find my bush of Therese Bugnet. The raspberries have been in the area since before I was even into flowers! I recall plucking them and enjoying them on many a pleasant summer's day.

    That is exactly the age of the canes affected too.