Sunday, September 20, 2009

Powdery Mildew on Zucchini

powdery mildew on zucchini 1
I first spotted the beginnings of powdery mildew on my fall zucchini a couple days ago. I knew I should have pulled the leaves but in the back of my head, I was hoping that the little bit that was there would not spread to other leaves. (Beginner's mistake.) I took a quick gander at them again today and it does appear to be spreading. I guess I'll have to remove the leaves now and hope for the best. Maybe I'll run out and get some copper spray. If anyone has any other suggestions, please let me know.

powdery mildew on zucchini 2
My 4 zucchini plants started flowering a couple of weeks ago. I still haven't gotten a female flower yet. If I don't get at least one zucchini out of this, I will be bitterly disappointed.


  1. powdery mildew usually only affects old and damaged leaves. You should cut them off as soon as you see the first sign of mildew. It is a good preventative measure to spray on a 10% milk 90% water mixture. Cover both sides of the leaves. This usually prevents PM spreading. If it gets out of control, copper oxychloride spray (it's organic)is best. Remember though, copper is residual in the soil for many years so don't spray it unless you have to.

  2. Thanks for the great info Rhonda Jean. I was a little wary about using Copper spray since it's already late in the season here in New England and I'm not sure the short term benefits outweigh the residual affects.

    I will have to catalog the milk/water mixture suggestion for future use!

  3. Very thinly sprinkled powdered milk will work on the leaves too. Spread it on as lightly as you can while the leaves are still just a little damp in the morning. It's worked like a charm for me.

  4. You may be doing this already, but be sure to keep the plants covered at night. If evening temps stay in the 50's I think you have a shot at getting some squash. Once the bees figure out the blossoms are there you can leave the cover on but pulled back in spots- they will find their way in.

  5. I've heard of the powdered milk solution, but have never used it myself. I hope you're able to salvage the plants and get at least a small harvest. Good luck!

  6. Good Morning, Thomas...thanks for the comment. So nice of you to drop by. I LOVED your story about the pumpkin patch...and seeing a thousand orange stars. Perfect. I agree..there is nothing like a pumpkin patch. We went to Mary's yesterday, but they were still setting up. Hopefully they will open this weekend. Can't wait to share the pictures with you.

    On the zucchini front.....I had the most dissapointing year in that department. Super hot in my garden..watered every day...faithfully, fertilizer of the organic variety..not ONE squash.

  7. I don't have any helpful advice...hope you get the zucchini that you want! When i used to grow them, the doggone plants were so productive, i used to wish that they would come down with some sort of disease or insect pest so i wouldn't have to keep picking (and finding things to do with) zucchini.