New guy from Ohio

[Dennis Griffith]

Powdery mildew question: I am just now seeing subtle, splotchy white-grey areas on leaves, and I'm about 3 weeks from harvest on my Marquette. Do I spray this late in the game, or would it be okay to wait until after harvest? If I need to now, Captan?

You can use either Serenade and/or Neem Oil safely. Captan also has a 1 day PHI, but may not be effective on PM. It is extremely effective on DM (downy mildew) though, which you may have. I'm basing this on all the research papers I've been reading on fungicide effectiveness. There is some contradiction between the different .edu papers I've read, but I've come to the conclusion that Captan is effective on many fungi, just not PM.

 

[shrewsbury]

I would follow above advice and add if you have 2 weeks till harvest I would use immunox.

 

[Dennis Griffith]

I would follow above advice and add if you have 2 weeks till harvest I would use immunox.

yes, Immunox is extremely effective on PM. I missed the part about you having 3 weeks. Immunox is 14 days PHI.