I have about 10 Euonymus (Emerald Gaiety) in my yard. A few have had a powdery substance on them. One of those is now 95% dead. The leaves turn from green to white, then brown/dead. I see no insects/leaves eaten. I have trimmed off dead areas before, and more occurs each year. 1) What disease is this? 2) If I just take out the dead one & replant a new one, will this "disease" continue?