Wednesday, June 10, 2009

Bagworms! Eradicate now.

Bagworms, found east of the Rockies, plague evergreens and other plants. Spray or handpick bags NOW. Eggs are hatching in those leather-like bags hanging on your evergreens. Larvae crawl out and feed on foliage, slowing destroying your beautiful plant in the process. Then they create their own "bag". Once they seclude themselves inside, they are impervious to any spray you apply.


How do you eradicate them? Spray or handpick bags RIGHT NOW. Spray the entire plant with malathion or check your local garden shop for another good product. If you are hesitant to use chemicals, then your next best method is to handpick and destroy the bags or spray with BTK, a microbial biological control (ask for it at your garden store).


If you choose to handpick the bags, use a knife or hand pruners to cut the silk from the twig. if you tear the bag off, you leave a coil of tightly wound silk. It will girdle the twig and cause a different problem.


If the bags are left on your plant, the caterpillars will slowly defoliate the plant, weaken it, and in a couple of seasons, or so, the plant will die.


Be aware that bagworms are not limited to evergreens. They will eat foliage from any plant and use it to create bags. So if you find them in evergreens, check every tree and shrub in your landscape. Vigilance is key in eradication and protecting your beautiful plants spring after spring.

3 comments:

  1. Hello! I just spent an hour cutting away a couple of hundred bagworm bags on the lower part of the tree (about 6-8 bags at the top were too high to reach). I ended up pruning most of the small branches with bagworms just short of where they were attached, rather than deal with trying to remove the silk bands attaching each bag to a branch–fortunately all the bags seem to prefer small outside branches. I didn’t see any “loose” worms anywhere on the tree, and I tore open a couple of bags and found the larvae inside (I know–yech!).
    Questions: this being late August in Maryland, will it help to have removed 97% of the occupied bagworm bags by hand, or is it just too late? And how resilient are cypresses once the bagworms are gone, and what can I do to help nurse the tree back to health? The bottom third of the tree is mostly defoliated, but the rest of it is still mostly green. Thanks for any advice you can offer! All the best, Erik

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  2. Eric,
    Yech is the right word. It is not too late to remove bagworms. Pulling and pruning is the way to go at this time of year to rid your precious tree of the bagworms. Do you have a neighbor with a long pole trimmer? If so, borrow it. Pole trimmers have a "cutter" on them that you could use to reach the bags at the top of the tree and cut them out. Burn them to be sure they are destroyed!

    I picked one off an ornamental shade tree at church today and squeezed it. It went "squish". Another yech. The "squish" means there was a live worm inside and probably 800 or more eggs!

    The best thing to do now to nurture your tree is be sure the tree is watered deeply this fall and use a good all purpose fertilizer around the tree out to the drip line next spring.

    Check with your local county extension agent to ascertain the hatching time on eggs for next spring. In Indiana, it is the first of June.

    As a preventative measure next spring, spray your tree at hatching time and then spray the tree again two to three weeks after the first time. This is the only time spray works, so it is important to get the timing right. Your county extension agent can help you with the timeing and selecting an appropriate spray for your area.

    Inspect other trees and plants on your property because bagworms will take up residence on any type of plant.

    Blessings, Wenda

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  3. Erik,
    Forgive me for spelling your name incorrectly. I seem to be technologically challenged and can't discover a way to change my comment to reflect the correct spelling of you name.
    Wenda

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