Question
I have a large blue sprice and just noticed I have bag worms. I have been pulling them off and stepping on them,  I got sevin spray with a hose, but want to use it to be effective,  since it is still hot in Maryland should I spray?  I cant reach the ones on the top of the tree, is this a lost cause, have you heard of success stories.  thank you.

Answer
Hand picking for small tree is the best method.Insecticides work well if the spray can be gotten on all the foliage. Sevin is OK here are other insecticides that are also recommended.

Insecticide Sprays Stomach insecticides are very useful for control of bagworms. Remember that the plant foliage is to be thoroughly covered because the larvae are protected from contact by being in the silk bag. Again, early sprays against young larvae are more effective than later applications. Products registered for bagworm control are: acephate (Orthene), bifenthrin (Talstar), carbaryl (Sevin), chlorpyrifos (Dursban),  diazinon, dimethoate (Cygon), malathion, nicotine sulfate, and pyrethrum.

There is a soil applied insecticide that work for the whole season but soon the tree will start to shut down for the winter so it is best used next spring. I would treat the tree with Bayer Advanced Tree and Shrub Insect control. This is applied to the soil around the tree and the roots will carry it to the foliage and when the caterpillar feeds they are killed. The treatment will prevent attack for the growing season. You should wait until spring since this time of the year the trees are beginning to shut down for the winter and have almost stopped moving water up from the roots. Next spring there will be a fast movement of water up and this will carry the insecticide with it. Here is a web link to this product--check with your local garden type store for it.

http://www.bayeradvanced.com/tree-shrub-care/products/12-month-tree-shrub-insect