Box hedge worries

we have noticed lacey threads, leaf drop and withered leaves on our box hedging. Worried that this is box blight or psylla buxi? The hedges are pretty well ventilated. It has appeared in the last couple of months and weather is pretty dry here in Fife. My questions: what is it? how or can it be treated?: is it OK to trim and hoover up waste? Any other advice gratefully received. Many thanks