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How do I treat a bag worm infestation on my evergreen shrubs?

April 1st, 2007 by admin

garden hoe asked:


I have an arborvitiae and two well established cedar shrubs that are covered with bag worms and the foliage is starting to turn brown. I live in Iowa. What’s the best treatment? Will my shrubs die?

3 Responses to “How do I treat a bag worm infestation on my evergreen shrubs?”

  1. Pobept Says:

    while in the bag, the only thing you can do is hand pick them and destroy them while still in the bag

  2. Big Red Says:

    My son is a professional nurseryman and he says if they are smaller, perhaps an inch or less, spray with Bt, [Bacillus thurgiensis]. Your local nursery should know about this and have it. If they are larger and you don’t perceive a worm in the bag, hand pick them off.
    They are in effect strangling the branches and you may eventually have to trim off some dead branches.

  3. judy_derr38565 Says:

    I have killed them by poking a hole in the bag and spraying with wasp and hornet spray, kills them deader than a door nail.