Diseased Viburnum

Can anyone advise on this problem.  I have a very large Viburnum shrub that turned brown last year and defoliated.  I had thought it was just the dry summer but this year after new shoots appeared they appear to be doing the same.  I don't think its beetle because it has had that in previous years, this is just a brown shrivelling away.  I have sprayed with Provado but not sure what I am spraying for really?