The several day period between the observed emergence and actual pheromone capture was a bit surprising. This native pest is our largest bodied clearwing pest and is common on lilac but also appears on ash and privet. Females lay eggs where the bark is loose or cracked, especially on dead center canes.
Heavy infestations cause wilting bark cracking, and branch dieback.
A better management practice is to prune out all larger center trunks. It may take a couple of seasons to do this. Pruning will have the added benefit of promoting new growth, resulting in more flowers and a more shapely plant. Mimosa leafs out very late here usually, but are now emerging. Wilt will be evident as brown streaks in the wood under the bark.