Good advice. Also, do you have new mulch at the base of the plant? If yes- I would push the mulch away from the base of the tree, about 18" circle, making a dish shape so rain water would collect towards the base of the plant. Then spray, and wash any tools you've used afterwards so as not to spread to other plants. If you've already sprayed, no biggie, I would still move the mulch away. And wash any tools too, just in case.