Bagworms can be destructive little pests. Bagworms create spindle shaped bags that can be seen hanging from the tree or shrub. They resemble pine cones or other plant material so they can sometimes be hard to detect. If you notice the bottom of your tree or shrub seems to be turning brown, and if you notice webbing (resembles spider webs) on the tree or shrub then you need to investigate further.
Bagworms prefer juniper, arborvitae, spruce and pine trees or shrubs. However, they can also be found in various other trees/shrubs. They are worms or caterpillar bugs that spin strands of silk to make a cocoon. They also use plant material to make the cocoon.
They can spread rapidly to other trees/shrubs so you want to get them removed as soon as possible. In order to successfully rid yourself of these pests you should destroy the cocoons. You can do this a couple of ways. First you need to go through the tree or shrub and pull all the cocoons off. Once the cocoons are removed you can either burn them or submerse in bleach water. Some people prefer to get bleach water in a large bucket and take it with you and as you remove the cocoon drop it directly into the bleach solution.
Once you have removed all cocoons you may want to have an insecticide sprayed. You can get an effective solution for this at a local home and garden shop. I recommend purchasing an organic solution. Make sure you have double checked the tree or shrub thoroughly and have removed every cocoon, then saturate the tree or shrub with the solution. I also recommend checking other surrounding trees and shrubs as they can spread quickly. This will ensure you have everything.