[oldcow]

One of my courgette plants has developed a couple of white patches that look like powdery mildew. What should I do? Remove the leaves? Spray with something? I'm trying to keep things organic, if possible; would a spray of chamomile tea help (somebody here suggested against fungal diseases in seedlings)?

[Aunt Sally]

Dilute milk I think (as long as you're not vegan)

Let me look it up.

[Aunt Sally]

http://chat.allotment-garden.org/index.php?topic=22433.msg268519#msg268519

Different plant but same principal.

[mumofstig]

1 part milk to 4 parts water is the mix I use 

[Aunt Sally]

I must try and remember those proportions Mum

[purplebean]

Any idea what it is in the milk that helps? I am vegan and drink soya milk, I am assuming that soya milk wouldn't work

[Aunt Sally]

This link might help.

If you use soya milk do let us know what results you get.

[oldcow]

Thank you very much, I'll try that (not vegan)! Is this something that needs to be done with a given frequency, or whenever the patches appear?

[mumofstig]

Pioneer Thinking: How does milk control powdery mildew?

Scientist aren't 100% sure how milk works to control this disease. It seems that milk is a natural germicide. In addition, it contains several naturally occurring salts and amino acids that are taken up by the plant. From previous experiments using sodium bicarbonate, potassium phosphate, and other salts, researchers have found that the disease is sensitive to these salts. It is possible then, that milk boosts the plant's immune system to prevent the disease.

I hope this helps  
I spray about every 10 days if it returns after spraying

[fatcat1955]

See if the marks will wipe off first, could be water stains from watering

[oldcow]

The marks do wipe off; does it mean it is or it is not powdery mildew?

[fatcat1955]

If you have a healthy looking green leaf then its ok. If you still have the outline and it looks like it is in the leaf, then its not ok

[Steve.B]

Buy the book.......

I think I read that it should be low fat milk semi skimmed.

Not tried it yet but will if I get mildew.