Powdery Mildew on Oak

[oldclaypaws]

I was delighted to see a fine crop of young Oak seedlings, literally hundreds, but have just noticed they are all suffering from powdery mildew. Apparently it is common and widespread, affecting young trees during dry periods and weakening their tolerance of shady conditions. It might explain why I have virtually no young oaks in my very shady mature oak wood.

Has anyone any advice for possible treatment so that some seedlings can survive and create the next generation?

[The Barrowers]

I have some potted young oaks and they have gone powdery white?

[jennysmate]

I have a bonsai oak I grew from an acorn, and some potted oaks ready to go in my wood. I spray with a fungicide just as the first green tips emerge from the leaf bud and again if I see any signs, removing the effected leaves. This seems to work. Young oaks do seem to be prone to this.

[oldclaypaws]

Apparently a quite aggressive new mildew which affects oaks in particular appeared worldwide in about 1920. It hits young saplings during dry periods around mid summer, dry roots and shadey conditions make it worse. I might consider digging up some of my surviving oak saplings, potting them, spraying with a mildew treatment and putting them somewhere more open in a 'nursery'. As Jennysmate says, there are effective mildew treatments but its very sad when you get excited seeing thousands of new saplings from last years acorns, reduced to one or two bedraggled survivors.

[Stephen1]

You might be interested to read what Oliver Rackham has to say on this subject - what he terms the 'Oak Change'.