I always use it at the 1st sign of powdery mildew on my roses and hydrangeas. I do the 10% (roughly-I'm not one to actually measure) and do 3 applications. It always does the trick for me!

In fact, due to the extra rainy spring we're having here, I noticed powdery mildew everywhere on Monday, sprayed on Tuesday, no sign of the mildew anywhere. I'll still spray them again just in case.

Try it, can't hurt... except for the milky smell that persists for awhile afterwards... and the fact that people will think you're nuts. Then again, I consider that aspect a benefit.

I read a study about the use of a 10% milk solution on grapes to combat PM. The study reported the milk was as effective as chemical treatments.

Encouraged I used a 10% milk solution on everything I grew that got PM and found it offered little.

To this day though if I have soiled milk I use it on plants rather than toss it.

My opinion, based upon my experiences with milk, is that it hasn't done anything for me, but it has been tested and found effective by others. I don't know what variables control it's effectiveness. I use it if the alternative is tossing it out, but don't spend money to buy it for anti fungal use.

Thanks guys. I also was reminded today that Organocide, which is something I have for my citrus, is used for PM.

And on top of that my local favorite nurseryman says he usually uses on his own stuff the baking soda, hort oil, water mix.

Not sure what I'll ultimately do, but it will involve some yanking and some treating of the least affected plants.

Thatnks!
-k

Actually, if you're going to spend money on something to combat powdery mildew, you might as well go with milk. It's been tested and proven to be effective against powdery mildew and even at the current high prices it's still probably less expensive than alternatives!

The fat free milk and water spray will work on Powdery Mildew on any plant. I have always mixed that spray 50/50 and found that most often the PM problem is solved with one spray, but you could mix it weaker and spray more often if that is your choice.

Thanks folks, I ended up spraying with the Organocide last night since thats what I had leftover from a citrus scale thing this spring. It's OMRI listed, just a mix of fish oil and sesame oil. Stinks to all get out. LOL

But if it continues, I'll try the fat free milk mixture.

Thanks!

I have used the milk (approx 30%) on roses and peas and grapes and it works wonders. I will sometimes come back a few days later and do an additional spray just to take care of anything left (not really necessary...). The reason I use milk rather than anything else is that it works, but also acts as a foliar fertilizer.

This is not the source I got it from, but gives some general info on milk for PM and as a fert.

Here is a link that might be useful: Milk in OG

I've also used milk at 10% on pumpkins, Hubbard squash and cukes. I've been able to control it with milk, not eliminate it, but repeated applications have allowed me to get crops.

Studies have shown that it makes no difference whether you use whole milk 2% fat-free etc. since the fat is not the agent that combats the mildew.

Wayne

Perhaps, those that spray less than the 50/50 mixture of fat free milk and water, what you are spraying is not enough to properly control the disease and that is why you need to repeat the spray to "control" that. Perhaps also spraying not enough to do the job will allow those spores to develop immunities to that material so it will be less effective in the future. That has happened with many of our current poisons, the target has developed immunities to the poison and it is no longer effective.

Zinnia's are my target for the milk mix and it works for me with the 50/50 mix...if I spray before I see the PM. Lets see, we've had 14 inches of rain since Memorial Day, maybe its Golden Guernsey time.

tj

Below is a link to a scientific study into the efficacy of diluted milk in controlling powdery mildew on zucchini squash. It is the only scientific research into the use of milk in this manner that I am aware of. (It is PDF format and requires an Adobe program to open.) Notice it deals with fresh cows milk (one would presume whole milk.) I'm not sure where the fat-free idea came from but haven't seen studies that support that nor has my successful use of whole milk or 2% shown any difference in success.

The study indicates low concentrations at more frequent applications are effective while less frequent applications requires higher concentrations.

An interesting observation is that the study indicates that the rate of control can equal the success of synthetic fungicides.

Wayne

Here is a link that might be useful: Effectiveness of Cows Milk......

Bettiol talks about using fresh milk, which in Brazil is raw, not pastureized, milk. Since few of us have access to raw milk, and the study I saw from the USDA suggested using fat free milk, this is what I have used, successfully at the 50/50 mixture to control PM. Most often one spray was all that was needed, if I sprayed when the first signs of PM appeared, but if I waited a bit that might require two or three sprays. I have not, in the many years I have used milk and water needed to spray every week. There seems to be some difference in the fat in pasturized milk versus raw milk.

Thanks for the link, Wayne. There seems to be something inherently pleasing when science reaffirms folklore.

kimmsr- I usually make two applications about 2-3 weeks apart. Not sure if I really need the second I just do it. Another difference in milk, as fat content gets lower, the calcium content gets higher in our milk. Some calcium molecules will kill mildew, maybe that is a factor-just guessing.

tj

Haven't come across the USDA study, Kimm. I'll look for it.

Wayne

This is my first post ever, but I search and read the postings pretty frequently and all of your advice has been very helpful. I am new gardener too, so I have a ton of questions.

I've been 'spraying' milk/water on my squash - 3 applications over 3 days, but nothing is happening. Should I expect it to go away. My plants have it pretty badly. Does it stop them from producing? Could it be that my system for spraying is more like drizzling? Any advice would be appreciated.

The usual application reccommended forr the milk/water spray is to apply it every 5 to 7 days, as needed. Give it time to work.

embarnet- I don't believe I have ever seen it cure the powdery mildew on any of my plants. It has been effective at stopping my plants from getting PM, and once the PM was there the milk may have slowed its spread, but I've never seen the PM disappear.

tj