Outside Looking In

Bagworm – A Creepy Little Insect

Doreen Maurer ZANESVILLE, Ohio- This is just a bit of information that you may find helpful.  This past fall someone brought this strange looking thing in a baggie to the office and wanted it identified.  It looked to me like something that could be a part of a pine tree.  It was pinecone shaped and was covered in what looked like pine needles and twigs, and then, it moved.   Suddenly, what was fascinating became creepy.  And this is how I was introduced to the bagworm. 

This was another first for me, I have never seen nor heard of a bagworm. So, to the computer I went to read about it.  I am writing to tell you that this fascinating, creepy little creature is a pest.  It loves to feed on many species of trees and scrubs.  It favors the arborvitae, cedar, junipers, and pine, but can be found in trees such as the sycamore, maple, and locust.  Its interesting appearance is made up of materials from its host tree.   

Bagworms are native to North American.   The adult female bagworm does not look like a moth but rather maggot-like with a soft body and does not leave the bag.  A mated female will lay up to 1000 eggs in the bag and will die.   The bagworm caterpillar will emerge from its bag sometime in late May to mid-June.   After the caterpillar emerges from the bag, it immediately starts feeding and will make Its own silken cocoon like bag.  This bag covers the whole body but the legs which allows the caterpillar freedom to move about to feed.  The bag is then covered with materials from the host plant (ingenious camouflage don’t you think).  The caterpillar usually will begin feeding at the top of the plant.  They will feed in the layers of the leaf tissue, leaving light brown patches on the leaf.   A severe infestation of the bagworm can defoliate the plant which may kill branches, and possibly the entire plant.   These little creatures are a hungry bunch and will move about to find food.  

In late summer, the caterpillar is mature and will attach its bag with a silk thread to the host plant.  It will then close the bag and begin the pupation stage of its development.   This usually will take seven to ten days.  The male bagworm will emerge from the bag as a moth with clear wings.  The female bagworm does not develop wings and will stay in the bag.  The bagworm moth will then fly to a female bag to mate.  As mentioned above, the female can lay up to 1000 eggs in the bag and then she will die. The eggs will remain in the mother’s bag until the next spring.  There is one generation of bagworms per year. 

There are birds and insects that feed on the larvae of the bagworm, so if the infestation is not severe, nature may take its course and control the bagworm population.  Severe infestation of the bagworm can be managed by biological controls and chemical controls.  However, the most economical way to control bagworms is to handpick and destroy the egg filled bag.  The bag can be picked from fall till spring.  Do not pick and drop the egg filled bag on the ground.  The eggs will still hatch. 

Please keep coming back to learn more about the fascinating and sometimes creepy gifts of nature.  Humm, I wonder what the story is behind the Praying Mantis.  Well, back to my computer . . .     

Remember to check out the other interesting things that are going on down here on Underwood Street.  If you ever have a question, please stop by, and see us or give us a call at 740-454-2027.  If we don’t know the answer, we will try to find it. 

2 Comments

  • DK wilson

    Another good one, Doreen! Also I learned a lot and took many notes during last night’s zoom mtg. Am planning to do some follow-up with that speaker.

  • Joan Myers

    Very good info. I had the exact problem on my pine trees in the yard. Robert had me spray because my infestation was so bad. But I had seen those bags the year before too. So it got a head start. My trees are still alive but not very nice looking. It got rid of the bags.

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