Matt, what's so tough about organics is that there is tons of experiments and "crossing one's fingers"....
For Japanese beetles the milky spore can be effective but sadly it's too hot and droughty cracked earth. You can't put Milky Spore unless there's just enough softness to the earth for it to set. It is a truly organic "lawn treatment and ground treatment" against JBs.
My way of dealing with JBs is letting my grass dry out completely hoping it will roast those larvae eggs. Then when the cooler weather hits I go with Milky spore.
So far the JBs are more sensitive to hot wax pepper spray than cucumber beetles which don't care at all, lol. Some species of thrips also hate the hot wax pepper spray, but some just totally destroy regardless Other people use traps and place it some distance from their property so that the beetles leave their property and get zapped into the traps. However those things should be responsibly emptied every time, lol!
The experiments I have heard that may work is having boiled ginger root and once it completely cools!! spraying those on the leaves. For ornamental garden plants, insecticidal soap actually kills the bad insects but I will only use it if it's a particularly bad infestation. Insecticidal soap is not exactly safe for the bees until it has dried. Neem oil is also not exactly healthy either. But what you can do is maybe spray before the bloomtime and after the bloom season has completely finished So far I refuse to use any insect-killers save for Milky Spore.
Kathy yes dormancy spray is a great idea to apply before winter hits that way it is sure to kill the future generation of leaf eaters, lol! I don't use it however, because too much lime/sulfur setting into the soil isn't good for the earthworms. But you have to pick your battles and assess which treatment causes the least amount of damage possible. Diehards like myself refuse to kill but we also have to sit and wait out the damage. It really teaches PATIENCE....And I also do the camera test. If I can take a photo or can step back 6' away and the plant/tree still looks good, then all is well! I live can certainly live with a few munch holes here and there.
Consider also attracting beneficials like birds (birdbaths and feeders). Buying ladybugs, etc.