Viburnum beetle on V Opulus roseum
We've got a lovely V Opulus roseum in our front garden. However, the last two years we have seen the leaves been eaten by what I believe to be Viburnum beetle. The leaves have a lacelike appearance. Advice includes tolerating and watching in spring, but it has got much worse this year. Last year it affected maybe a quarter of the tree, now it is more like two thirds. I don't want to use pesticides. Is there any hope for our tree? I have heard of 'winter wash'. Is there a safe biological way to that?