I planted 2 lilac trees this past spring (april) and did really well for months. the person at my local nursery helped me with how to do . they really were not big when I purchased them probably 4 ft tall. anyways they are still growing new growth but on the older parts of the plants there is a weird white film. some sort of fungus maybe? I have no idea, I purchased a spray from the same nursery that they swore was natural and ok for lilac trees, well I almost died spraying it, the smell was wretched and I had to get the kids in the house it was that bad, it was called seranade disease control. some of the leaves are now brown and brittle.... does anyone know what this white film could be and how to get rid of it as natural as possible please. Lilacs are my absolute favorite and I would love these trees to bloom next spring.