It's not too late to protect vulnerable plants from Japanese Beetle attack!
I wouldn't be surprised if Japanese Beetles show up middle to late June instead of the beginning of July.
I recommend Bayer for systemic Japanese beetle control, there's a type of Bayer for whatever you need to protect. The larger the plant (trees) the sooner you need to apply your systemic beetle control because it needs to get absorbed by the roots and distributed throughout the entire canopy. Susceptible plants include: Linden and Birch trees, Rose bushes, herbs, like Basil, and fruit and veggies, like Grape Vines.
Also, don't forget to do your mulching and deep watering now, since we have had such warm, dry, and windy weather. If we don't get one inch of rain a week, give trees and shrubs one inch of water per week.
The ideal way to do this is using soaker hoses. An easy and unobtrusive way to install one for permanent use is to lay them out around the area you need to water and cover with a few inches of mulch.