I'd be careful with any type of foliar spray for Japanese maples. They have rather sensitive foliage that easily develops phytotoxicity with insecticidal soaps or oil-based sprays (Neem, horticultural oils, even cooking oils like canola). Most garlic spray preparations have some sort of an oil base to help them adhere to the foliage.

Why not simply try hosing down the foliage with a strong stream of water? That is typically sufficient to deter sucking, soft-bodied insects like aphids, which tend to feed off the newest, tenderest growth and result in some leaf deformation.

gardengal,

thanks for the reply. I had checked(with a magnifying glass) all the leaves and their undersides for aphids or spider mites and did not find any. So it must be something that does the damage and then flies or moves away from the tree. Hence the thought of the garlic spray.

thanks,
xman