I'm not big on chemicals but we had a really bad infestation of Japanese beetles on my Plum & Cherry trees & Aphids on my Apple trees a few weeks ago. I bit the bullet & bought some GardenTech Sevin spray & mixed at 4 oz/gal. like it said. I also sprayed my Pear trees but noticed my Pear tree leaves area now a brownish green instead of the bright green they were a few weeks ago. All my Pear trees are roughly 3 years old. Is Sevin not good for Pears? Is there something else I can do or something else I can spray my trees with that's not as potent as Sevin?