Q.Rhododendron
I planted 6 rhododendron bushes several years ago. Last summer I noticed that I was having branches die off. I was told that I had either borers or beetles. I lost 3 bushes but managed to save the others by applying Orthene every two weeks to them all. Have neighbors with rhododendrons, no problems with them. I thought that these bushes have little or no serious problems as I experienced. Maybe you can shed some light on this subject with your expertise.
Thank you your attention in this matter, I appreciate your input.
Ed Dyer
It is best to make an identification of the specific pest that is invading your plants, there are a few common pests.
Here are some links with more information.
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/issues-with-rhododendrons.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/rhododendron-care.htm
https://www.gardeningknowhow.com/ornamental/shrubs/rhododendron/how-to-fertilize-rhododendrons.htm