Cocoon on Oak Tree Branch?
Hi — I found your website through Google. I live in central Missouri and found this "weird growth" on a branch of one of the oak trees in my yard. I’ve tried researching the web, but I still can’t identify if it’s a plant fungus, or a gall, or a bird nest, or a cocoon, or something else! Do you have any idea? It’s about the size of a ping-pong ball, white with pink spots, and it’s "perched" on top of the branch. Very strange. Thanks!
In the true sense of the word, this is not a cocoon though adult insects will emerge. You have a Wool Sower Gall which is produced by a tiny wasp, Callirhytis seminator. Galls are growths on various parts of plants, usually caused by a Gall Wasp or a type of mite. There are many species of Gall Wasps, and each has a specific host plant. The Wool Sower Gall used the oak tree as a host. Here is a site with additional information.