What is this hard cocoon/nest/growth on my baby key lime tree?
My little key lime tree is in a 10 inch pot on the deck. It will winter inside the house. I noticed this "thing" attached to one of the branches. It is about 1.25 inches in length and is hard to the touch. It appeared within the last week or so. What is it? What should I do about it?
This is a praying mantis egg case. The eggs overwinter in this case and then hatch in the spring. Praying mantises are predators of other insects in the garden. You could just remove the case from your plant before you bring it inside, or prune out the branch with the case and set it outside in a shrub where it can sit for the winter. https://extension.umd.edu/hgic/insects/predators-praying-mantid-mantis
Thank you for such a fast response! I have looked at the link, but it does not tell how to remove the egg case from the branch. Should I cut a slit on one side with an exacto knife?
It's such a small branch that we would recommend that you snip off the branch with the egg case attached. You can't really remove the egg case without damaging the eggs somewhat, but an Exacto knife may cause less damage than something else. There is no particular method that we know of. The smaller the slit the better.