Saturday, September 14, 2013

The Good, The Bag and The Ugly -- a Lesson in Bag Worms

We saw one last winter on our blue spruce and removed it.  Then a couple of weeks ago, we noticed about a hundred of them hanging from branches all over the tree.   What are they?   Bag worms.

The bag worms really is the pupa stage in the life cycle of the Psychidae or case moth.  The caterpillars create a silk case using the foliage of the host tree and pupate inside the case.  The adult male emerges in seven days as a furry, gray moth with clear wings, but the female bunkers down for the winter, living in the bag from late August through early spring of the next year.  Inside she lays between 300 and 1000 eggs!

This is the time of year to look for these "bags" on your trees.  The moths will set up housekeeping using a variety of trees, constructing their bags from the leaves of that tree.  So, investigate your trees now, looking for leaf-covered, hanging cocoons.  If you do see any, they can easily be removed by plucking them off.  Better to do it now than wait for spring like we did this year.... or you may end up with hundreds of bags next September!

We have so many bags on the blue spruce in front of our house that we need to make a decision whether to remove each one and burn them, or remove the whole tree and burn it.

While we value a good blue spruce tree for its beauty, we would not hesitate to destroy this one.  Why?  Its size (too big), location (right next to front steps) and its odd-shape (top plucked off --possibly used as a Christmas tree by the previous owner).  In addition, the defoliation from this infestation and past infestations have made this tree bare in many places.  In sum, the tree is ugly.

Want to weigh in?  Is it worth removing about 100 bag worm bags and trying to save the tree? 
Have you any experience with bag worms you can share?
Happy Trails,
--Two Peas

No comments:

Post a Comment

Please leave a comment for me. Thanks!