Hi

I have a Sweet 100 climber growing behind a clump of Black Eyed Susans (Autumn Gold).

Today I noticed that the back of the BES has a little powdery mildew. It's leaves are almost close enough to touch the bottom of the tomato plant.

I removed some stalks/branches inbetween those two plants to let more light and air get in there.

How susceptible to PM are these tomatoes? Both plants look perfectly healthy, otherwise.