Ahhh, milk....specifically "raw milk", an interesting and grossly misunderstood liquid.
Raw Milk (unpasteurized without additives) has protein (amino acids), bacteria, vitamins, trace elements, salts, and of course fat and lots of water.
This particular research is very informative--
http://www.researchgate.net/profile/Wagner_Bettiol/publication/222480569_Effectiveness_of_cow%27s_milk_against_zucchini_squash_powdery_mildew_%28Sphaerotheca_fuliginea%29_in_greenhouse_conditions/links/551470f60cf260a7cb2afb7f.pdf But unfortunately it is in a "no-print" format, so it truly is a "read only" document.
The study concluded:
"Cow milk may have more than one mode of action in controlling zucchini squash powdery mildew. Fresh milk may have a direct effect against S. fuliginea due to its germicidal properties (Salle, 1954). Milk contains several salts and amino-acids (Martins Filho, 1987). These substances have been shown to be effective in controlling powdery mildew and other diseases (Reuveni et al, 1993/1995; Mucharromah and Kuc, 1991; Titone et al, 1997; Pasini et al, 1997). Several authors have shown that sodium bicarbonate, oxalate, dibasic or tribasic potassium phosphate, and other salts and amino-acids have been efficient in the induction of systemic resistance (Reuveni et al, 1993/1995; Mucharromah and Kuc, 1991; Titone et al, 1997; Pasini et al, 1997; van Andel, 1966). Therefore milk may also indirectly affect S. fuliginea by inducing systemic resistance."
BTW, one of the best foods for bacteria (growing medium) is....Raw Milk. Funny thing...and at around $4/half gallon (skim variety)--it is super affordable!
Found it...here is the link to a "non-protected" text version of that study.
http://www.agrar.de/agenda/bettiol.htm