Question
My bush has developed tiny whitish spots on most of the leaves; Leaves have withered and died. Most branches seem dead. What has happened? Significant rainfall this year. Soil is acidic. Should I bother with new euonymous plants?

Answer
The most probable explanantion is scale insects.  If you dig through the whitish looking areas you will find little cigar looking structures.  These will be the living and dead bodies of the scale insects.  They do not move when touched.  They can have caused the death of your euonymous.  If the plant is not totally dead, I would treat the plant with Bayer Advanced Tree and Shrub Insecticide.  This product is mixed with water and poured on the soil around the base of the plant.  It is taken up systemically and will kill the bugs within a week or so.  It also provides protection from reinfestation for up to a year.  Cut off any dead branches and see what happens next spring.  You will probably need to treat then as well.  Good Luck.