Tuesday, September 9, 2008

Mysterious cocoon or tree killing worm sac?

A friend has helped us unlock a mystery that has been bugging Holden and I few weeks now. This is not for the squeamish.

Our mystery began when Holden spotted some very interesting cocoons a few weeks ago at a park in West Des Moines. The cocoons were dangling from the wire mesh around the base of the tree and they were made from leaves of a nearby tree.

Holden found one of the cocoons hanging from a plant stalk by the tree and we decided to bring it home. It is in a container and we look at it everyday wondering what will emerge. We didn't suspect anything unusual or we would have contacted Iowa State University to have it identified by the entomology department. We have sent photos of bugs and snakes to various local gurus with help identifying.

We found out from a friend (thank you, Renea!) that it is a bagworm nest sac. I can't wait to tell Holden all about it when he wakes up. He will be as fascinated as I have been this morning. There are about 500 - 1000 bagworm eggs in each sac and they are set to hatch out in the spring. My friend saw a clip about them on the news recently and passed on the info. I watched it and the local entomologist say these bagworms kill trees. The weather we had this year was ideal for a bumper bagworm crop. Iowa is not the only state in danger of a major bagworm invasion (I Googled bagworm). They can make their sac out of any type tree materials so they blend in to look like part of that tree.

Here's the link to the local news clip (I am guessing the clip will only be available for a few days or week): http://www.kcci.com/video/17423054/index.html

Here's a youtube video about them from garden expert, P. Allen Smith:


Jack said...

Cool! Well, in the sense that you figured out the mystery. can't say i've ever seen these guys...



Heather's Moving Castle said...

Just wanted to add that I read on a website that some people cut open the sacs for birds to eat the worms. That gives me the itchies, but it sounds like a good idea.