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Got Powdery Mildew? Got Milk?

K

Kal-El

I thought this was definately interesting.

By: Arzeena Hamir

Less than 3 years ago, researchers in South America discovered a new alternative to controlling powdery mildew. Wagner Bettiol, a scientist from Brazil, found that weekly sprays of milk controlled powdery mildew in zucchini just as effectively as synthetic fungicides such as fenarimol or benomyl. Not only was milk found to be effective at controlling the disease, it also acted as a foliar fertilizer, boosting the plant's immune system.

Powdery mildew in the cucurbit family is caused by the organism Sphaerotheca fuliginea. It is a serious disease that occurs worldwide. For decades, organic gardeners had to rely on making a spray from baking soda to control the disease. Now, instead of measuring out the baking soda and combining it with a surfactant (a "sticking" substance) of either oil or soap, gardeners need only head for their refrigerators.

In his experiments with zucchini plants, Bettiol found that a weekly spray of milk at a concentration of at least 10% (1 part milk to 9 parts water) significantly reduced the severity of powdery mildew infection on the plants by 90%. While some gardeners may be tempted to increase the concentration of milk for more control, Bettiol found that once concentrations rose above 30%, an innoccuous fungus began to grow on the plants.


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.

Milk used around the world

The benefits of using milk to control powdery mildew haven't been isolated to Brazil. Melon growers in New Zealand are saving thousands of dollars every year by spraying their crops with milk instead of synthetic fungicides. The melon growers in New Zealand have been so successful that the wine industry is taking notice and beginning experiments using milk to control powdery mildew in grapes.

What kind of milk should be used?

In Bettiol's original experiment, fresh milk was used, straight from the cow. However, this is obviously not feasible to most home gardeners. The research work in New Zealand actually found that using skim milk was just as effective. Not only was it cheaper, but the fact that the milk had no fat content meant that there was less chance of any odours.

Wagner Bettiol's original article was published in the journal Crop Science (Vol. 18, 1999, pp. 489-92). It can be found on-line at:
http://147.46.94.112/journal/sej/ful...908_180801.pdf
© Copyright Arzeena Hamir
Arzeena is an agronomist and garden writer with Organic Living Newsletter.
 

swishaman

Active member
Excellent find. Who would have thought of trying milk of all things? I wonder if milk from different species could potentially work 'better' ? He mentioned odor from the milk, so I wonder about that...
 
sort of off topic, but it's interesting none the less. if you ever want to kill a tree, put some holes in the base of the tree and poor milk in it & it kills the hell out of it. I have no idea why it does, but it does.
 

Thundurkel

Just Call me Urkle!!
Veteran
Awesome post!!!! plus rep to you my friend I've been battling PM for a month or 2 now and don't have money for special sprays and such so this is interesting for sure..
 

Hydro-Soil

Active member
Veteran
sort of off topic, but it's interesting none the less. if you ever want to kill a tree, put some holes in the base of the tree and poor milk in it & it kills the hell out of it. I have no idea why it does, but it does.
Um.... I'll take a guess and say the milk spoils and creates a wonderful environment for some very virulent bacteria to grow.

Probably kill you too if you had it festering in your own leg. :D
 

FreezerBoy

Was blind but now IC Puckbunny in Training
Veteran
Awesome post!!!! plus rep to you my friend I've been battling PM for a month or 2 now and don't have money for special sprays and such so this is interesting for sure..

First time I had PM I threw out all my plants and started over. PM came right back. So I threw out all the plants and disassembled the grow room and sterilized everything in a 5% bleach solution. Never saw PM again.
 
But how late can you use milk in the flowering process. Or should you only use it during veg? It must effect the taste of the finished product, right? Even if you do use skim milk.

world peace,
ILL
 

kmk420kali

Freedom Fighter
Veteran
But how late can you use milk in the flowering process. Or should you only use it during veg? It must effect the taste of the finished product, right? Even if you do use skim milk.

world peace,
ILL

Good call!! I would not spray milk on my flowering plants...it rots!! Quickly!!
If you have PM late in flower, IME nothing you spray will help, as it just adds to the moisture trapped in the buds, upping humidity...and makes it worse--
Altho my experience was with rather large grows...200+ plants-- So it may be different for a smaller grow--
Peace--
 

10k

burnt out og'er
Veteran
This method has been around for eons, we even had it in the growfaq at og back around 1999.
Use the dry powdered non fat milk, it will wash away later on and wont decay like a dairy fat would.

I totally agree with kmk420kali regarding spraying late in flowering.
Best to do everything you can to keep the buds from retaining moisture. Dehumidifying and ventilating full time especially all night when the lights are off and the plants are transpiring a lot of moisture is very important.
 

demasoni

Member
1 part skim milk 9 part water? or is that only for whole milk?

I have some 2% milk, how should I combine it with water?

consider youre outdoors- during mid to late flowering there is even more bud mass so its even more susceptible to mold is it not? you still need to use something; your threat is continuous moisture for the mold to set in, not so much temporary moisture of a anti fungal spray or milk..
obviously you want to use milk preventively during earlier to mid stages of flowers, but then just stop?especially if mold has set in?...
if you spray in morning outdoors for example for a full day of sun and lower humidity the moisture should evaporate by the end of the day, leaving behind the basic residue that helps prevent the mold. Thats how I understand it to work, is that correct? I will give it a try.. one 7 foot plant alone took almost a whole spray bottle of concern soap..thats NOT going to work for reapplication after every rain, way too many trips to the store and $.
I will give milk a try with ~25 days left and post the results. no other options
 

ricksiri

Member
milk

milk

discovered PM on some of my plants today.

sprayed them w/ 1 part milk (all i had was whole milk, we'll see how it works) to 9 parts water solution this evening.

put another circulating fan in the room. put my exaust fan to run round the clock.

I'll let you know how it comes out.
 

Momerath

Active member
I'm kinda battleing PM as well outdoors, and heard about this (the milk) the other day from a local grower so there must be some merit to it. I guess I'm just interested if anyone has any experience with this outside about a month or so from harvest?
 

ricksiri

Member
so far so good...

so far so good...

as of tonight, no PM on any of the leaves that had it before.

can't smell any milky smell...just wonderful "ode de skunk":woohoo:

plan on spraying again in a couple of days.

oh yea...i'm 4 weeks into flower...humidity shows 59% on my meter.
 

nephilthim

Member
I know powdery mildew won't propagate below 50 percent humidity so get a dehumidifer or adjust your a.c. running a.c in my shed if the temps got too low humidity got higher from condensate,allowing powdery mildew to flourish.I have used a combo of physan and h202 helped kill most pm one option that an icer recomended was j.s stylet oil.
 
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