White powdery mildew on my Zucchini leaves!!

I noticed that the leaves of my zucchini plants started to turn a bit white a few weeks ago.  I thought it was because I was spraying the leaves with the old 'soap and water' trick - you know, to ward off pests.  It turns out, that with a good 'ol google search (of course) that it's actually a fungal infection, and can completely destroy my plants and the fruit!  At this point, the leaves are REALLY white.  I waited FAR too long, but now I know what to look for. 

The beginning of a fungi problem on zucchini leaves.

Now I know why too... the hose attachment broke, and our garden hose got shorter (my brother-in-law took his attachment back), so I've had to water from above to reach everything.  It's a shame, cause the fungi has spread now :(

Anyway, this is the information I received from the following link at About.com:

http://gardening.about.com/od/gardenproblems/qt/PowderyMildew.htm

...You may not notice a problem until the top surfaces of the leaves turn powdery, but powdery mildew can also affect the lower leaf surface, stems, flowers, buds and even the fruit.
...it does stress the plant and severe or repetitive infections will weaken the plant. If enough of the leaf surface becomes covered with powdery mildew, photosynthesis is impaired. 

What Causes Powdery Mildew?

Powdery mildew fungi seem to be everywhere. They overwinter in plant debris begin producing spores in the spring. These spores are carried to your plants by wind, insects and splashing water. Conditions that encourage the growth and spread of powdery mildew include:

• Dampness or high humidity (Not common during rainy seasons or in extreme heat)
• Crowded plantings
• Poor air circulation

Controlling Powdery Mildew

• Choose healthy plants and keep they growing healthy
• Try and find a powdery mildew resistant cultivar, if your area is susceptible
• Don’t plant non-resistant varieties in the shade

Once Your Plants are Infected:

• Remove and destroy all infected plant parts
• Improve air circulation by thinning and pruning
• Don’t fertilized until the problem is corrected. Powdery mildew favors young, succulent growth
• Don’t water plants from above
• Most fungicides will need repeat applications every 7 - 14 days, for continuous protection. Always follow the label instructions for both application and waiting period before harvest

Of course, I want to maintain an ORGANIC garden, so this is the method I think I will try (also from About.com) :
http://gardening.about.com/od/gardenproblems/qt/PowderyMildew.htm

Baking soda makes an inexpensive control for powdery mildew on plants. The baking soda fungicide is mostly effective as a preventative, offering only minimal benefits after your plants have become infected. Weekly spraying of susceptible plants during humid or damp weather can greatly reduce the incidence of powdery mildew in your garden. To control powdery mildew on plants, mix together:
• 1 tablespoon of baking soda
• ½ teaspoon of liquid soap
• 1 gallon of water
Do not store unused mixture. While this recipe has been known to be effective, it can burn the leaves of some plants. It is recommended that you water your infected plants well a couple of days before applying this mixture, and don’t apply it in full sun. Try on a small area first, to test the plant’s response before spraying the entire plant. Some recipes also recommend applying 1 tablespoon of ultralight horticultural oil to the mixture. The oil coats and smothers the fungi. The soap is added to help the mix spread and cling to the leaf surface. Be sure to apply to lower leaf surfaces as well. I guess I'll get pruning and spraying tomorrow!!!