Black Vine Weevil in Heuchera

Discussion in 'HortForum' started by Jennifer Cook, Oct 2, 2016.

  1. Jennifer Cook

    Jennifer Cook New Member

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    Location:
    Kamloops, British Columbia
    This morning, I noticed one of my established Coral Bells did not look so good. When I lifted the leaves to have a look, the whole plant came away from the ground – completely severed from its roots. Upon further inspection, I found what I believe to be Black Vine Weevils in the crown of the plant. See photos.

    2016-10-02 14.09.53.jpg 2016-10-02 14.08.44.jpg

    Earlier this year, I had problems with spider mites on the adjacent Barberries, but they now seem OK.

    Close by (about 12 feet away), I have Burning Bushes with leaf damage consistent with the adult beetle. I had originally thought the damage was from grasshoppers as the plants seem otherwise healthy.

    It has not been a good season for this south-facing part of my garden, to say the least. Tough conditions with high daytime temperatures and wind.

    I've looked for information online on how to control and/or protect my plants from further damage, but it seems I am too late in the season for biological control, and too late to hand-pick the beetles. I am located in Kamloops, British Columbia.

    I did find an article which talked about the use of a systemic insecticide, but no further information on whether this is available for home use, and if it is toxic to other, beneficial insects. Here's a link to the article: hortnews.com/season-long-vine-weevil-control-is-back/

    What are my options? Am I likely to lose my Burning Bushes, too?

    I know I will have to do something in the spring to rid the soil of the larvae before planting again where the Heuchera was located. I'd prefer to use the least toxic methods, but would also like to keep my plants alive!

    Advice will be greatly appreciated!
     
  2. Houzi

    Houzi Active Member 10 Years

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    Location:
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    I always now use nematodes,though usually on containerised plants but they can be used in the garden.I find it much more economical than chemicals.Now is an ideal time to use them,you just make sure the soil is damp and above 5degrees to enable them to move thru the soil and give the area a light sprinkling with the nematode/water mix,they will move thru the soil hunting grubs.
    In UK 'Nemasys' is the brand specifically for vine weevil grubs,a £10 packet treats 12sqm...no fussing about calculating doses of chemicals.
     
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  3. Sundrop

    Sundrop Well-Known Member

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    Location:
    Kootenays, BC, Canada
    In addition to Houzi's advice here are a few links you may find useful:
    How to Control Black Vine Weevils | Planet Natural

    and
    What is a systemic insecticide? - Insects in the City
    You Bet Your Garden - 'Systemic' Pesticides Poison Every Pore of Your Plants

    As for the long run approach I 100% agree with the last statement in the article in the last link that "a natural feeding program based on improving the health and life of your soil is the most reliable 'systemic' response to virtually any problem."
     
    Last edited: Oct 3, 2016
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  4. Houzi

    Houzi Active Member 10 Years

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    That 'DE' sounds interesting Sundrop,I'm amazed that any insect can get scratched to death!..oh And I've just put in a load of Cyclamen...thanks for the warning(via the website)
     
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  5. Jennifer Cook

    Jennifer Cook New Member

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    Location:
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    Thank you both for your feedback!

    I have contacted my local garden center and they do have the nematodes in stock, so I will give that a try. I am fairly high up in elevation – it was only 3 degrees C this morning, so I am approaching the end of my window of opportunity. I'll apply them again in the spring and hope for the best!

    Due to all of the issues in this plot, I do also need to improve the soil. This was a bed installed by the builder of my home and it is obviously lacking.
     
  6. Houzi

    Houzi Active Member 10 Years

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    Yes,good luck,sounds like you've got the grubs in there and this is the time they do the damage.
     

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