I talked to ArborJet rep as the first tree we noticed was one we injected a week prior. But I had also gotten a call from a client where we just did soil applied imidacloprid. Another arborist in the area found some leaf drop from untreated trees as well as treated.Sounds like the same puzzle I've got with a white ash in Durham, NC. Sudden and premature leaf and petiole abscission with no signs of damage from insects, anthracnose, etc. Alarming because it started happening shortly after our emamectin benzoate injection. Lots of rain (too much rain), but flooding doesn't seem likely. The leaves in the photo below have been on the ground awhile. Client had been raking them away. These were the last batch that came of the tree but the shedding apparently started tapering off.