Answer: Catalpa does not have a reputation for playing host to wood boring pests, but it is susceptible to fungal wood decays. It's important to determine whether the insects arrived after decay began, or if there is no decay, whether the insects just chose to attack the smaller branches on your tree because they were handy.
Sounds like the pests are gone now and your best course of action would be to prune the tree to remove the damaged branches (and any eggs that might be present). If you can find one of the pests, you can take it to your local Cooperative Extension office for positive identification and current control measures.
Contact Sonoma County Cooperative Extension, 2604 Ventura Ave., Rm 100, Santa Rosa, CA 95403. Phone 707-429-5532.
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