I found this bag warm type object in my ornamental cherry tree today and has...
Thanks for using the Ask a Master Gardener with your question about the insects on your cherry tree.
I really cannot see the caterpillar up close in the photo to help me identify what you are dealing with, but if there is only one case and you have removed it from the tree and destroyed it, you should not have any more issues.
The "bag" could be an overwintering egg case for the moth or butterfly that laid the eggs or a "web" type silk bag spun to protect the growing caterpillars. That would have been made by the young caterpillars.
Caterpillars that I would think of would be the Eastern Tent Caterpillar and the Gypsy Moth. I am attaching fact sheets about both for you to consider. Again, if there was only one "bag" and you have removed it, the problem is solved. Bag Worms do not have that type of structure and they are not hatching yet. I will attach a fact sheet on them as well to help you.
Eastern Tent Caterpillar
If you have not done so and since the infestation is small, simply remove the mass and destroy, making sure to remove all the caterpillars. They will not harm you.
If you prefer chemical control, you may spray a product containing Bt, a bacteria that kills only caterpillars from the moth and butterfly family. It will not harm anything else in the environment. Or you may spray with any labels chemical for control of caterpillars. Please read and follow the label instructions.
If you want to know what insect it is, please take a sample to your local Ohio State University Extension Office at:
Cincinnati, Ohio 45223
Thanks for the question.