I'm hoping you guys may be able to help me out. I have a friend that just called me, and has a question. He has been using a mix of bifenthrin and imidicloprid to do foliar sprays for Japanese Beetle as well as a few other pests. This mix is with .5 oz. per gallon. Now,...he has 4 Birch trees that are wilting in leaf and dropping. I told him that it may be just coincidental, and that this might just be brought on from the culmination of heat stress. I also said that it is possible that it could be some sort of fungus (as conditions have been perfect). He said he has not yet been able to see the leaves yet (this was just a call he got). He is gong to get some clippings and show them to me, so I can get some photos. He also said that out of many other birch trees he has treated, no other trees have done this. I know that this is probably brought on from the causes stated above, but he is pretty upset (worried) and wanted me to ask you guys if anyone has had any experience with this. Thanks ahead, guys...and hopefully you will be able to add some insight.