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......

Thanks, Cupshaped, for the pictures. Beginners should notice the leaves showing their undersides-- this lets you spot PM from a distance before it even produces the white stuff-- although older leaves that have stiffened up usually won't show that. Fertilome Systemic is propiconazole, same as Banner and Bonide Infuse. It seems to be as effective as anything. I read a disturbing study the other day that found even the best fungicides ineffective when rose plants were already heavily infected and conditions for disease were optimum. So picking off infected leaves and stems makes sense in that context. My primitive sulfur fungicide has done nearly a perfect job of preventing PM this year, except on the no-spray roses that don't get blackspot, and which now are getting sprayed. Sulfur is widely used in agriculture for PM, so it is effective, but only as a preventative. Drought doesn't cause PM, but rain twice a week goes a long way toward preventing it. I washed down my roses this morning before spraying. PM germinates only on dry leaves at very high humidity, with temps mainly in the upper 50s and 60s F. These conditions occur mainly at night when the temperature holds for a few hours just above the dew point. Fog and heavy dews suggest PM conditions. PM is unlikely to germinate if the dew point is below 55, or if night temps are above 71, because dew points above 70 are pretty rare. Daytime temps in the 70s-low 80s are ideal for mycelial growth and release of spores. As Ann says, it doesn't like hot weather much. (from Horst's Compendium of Rose Diseases)

rhizo: Housekeeping, as in, removing diseased dying leaves? I have been for pumpkins, not so much for my cucurbits because they are very dense. I remove what I can, but there are some dead leaves pretty buried within the vines. I am not sure the cause of the dead leaves (is there a natural amount of leaves that die on a vine from "natural" (i.e., non disease/pest) causes? I'm going to post another problem today with photos. Some of my butternut squash leaves are VERY chlorotic, and some dying, and I can't tell the cause, as others are healthy and green. (I don't think it's PM, but who knows?) I look forward to your expertise(s). rhizo ... if there's something else I'm missing as far as "housekeeping" is concerned, please let me know! :) Thanks for taking the time to be concerned and answer. -Veronica

Potassium bicarb works a bit better but sodium bicarb works to some degree if you diligent. You can also try milk about 1 to 2 dilution, as well as vinegar 3 tbsp to gal of water, mouthwash 1 to 3 parts etc Neem oil helps as well.