Powdery mildew

[Smithyard Farm]

Hi all!

Does anyone have any ideas on powdery mildew? I have had a terrible time the last two years with it. This year I kept it (sort-of) at bay with neem oil.. however, it still eventually took over and I was unable to stay ahead of it. I had 9 zucchini plants and only 7 zucchinis. I pulled three and completely started over with three new plants.. but still had trouble. I know it over winters and am so upset that I cant get a handle on it. I was thinking of putting hay and leaves on top of my beds and lighting fire to it!!



any suggestions??

 

[so lucky]

Welcome to the forum, Smithyard Farms!
Any chance the plants are crowded or in a place where air can't circulate among the stems? I don't know much about powdery mildew, but I think one of the issues is humid, still air around the plant. How big do the plants get before powdery mildew gets them? Are they full grown and producing, or still seedlings?

 

[Smithyard Farm]

thanks for the welcome!

they are spaced fairy far apart. but I thought would give them extra room. and yes, we had a very wet humid season 3 summers ago at the of the year, it was awful and (my first taste of it) I didn't think much of it, it was September when it finally hit big time, and season was most gone.
the next year it came earlier, but at least I knew what it as this time, and treated with neem oil. It worked for a bit, but I lost all my plants again. This year I was prepared, I had heard that it can over winter, so I bought neem oil at the same time bought sees and had it ready. I even sprayed prior to seeing anything, It is effecting my squash (all varieties including pumpkin) and cucumbers. I am (almost) ready to throw in the towel...

 

[Chickie'sMomaInNH]

powdery mildew seems to be a problem in our area. there are some varieties that aren't prone to it. i believe butternut squash is resistant to the fungus, but it seems zucchini tend to be very prone to it's ill affects. see if your local garden center or feed store carries Bonide copper dust (copper sulfate). it is organic and can be mixed into a spray for use on the plants.

this UC Davis site is of good help too.
http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7406.html

 

[catjac1975]

A good way to keep the squash going is to plant 2-3 crops consecutively. I plant seedlings and seeds around the same time and then more seed by the 4th of July. When the first dies back the second is ready for more fruiting. This is a good way to keep the pests at bay also. I do not see why neem would do any good. I thought it is an organic insecticide. Milk is supposed to keep mildew at bay. I have found it works on roses but like anything else you have to keep at it. I believe baking soda is also an effective remedy.
There are also resistant squash varieties.

 

[digitS']

Welcome to the forum, Smithyard Farm !

I do as Catjac does. The plants set out about the 4th of July may have mildew by the end of the growing season if it is a bad powdery mildew year. Still, they are on their first legs rather than their last legs. I find that a good place to put that 2nd planting is between the early cabbage and broccoli plants. They take up about the same amount of room and the other plants can come out of the ground in early July.

The link Chickie'sMoma posted tells us that it is the horticultural oils that can protect the plants from mildew. Neem oil is one of those.

Yes, and mildew resistance! I planted Black Beauty kind of by accident several years ago. The bad mildew just about killed those plants by the end of August. Usually, I grow Ambassador and Aristocrat have "intermediate resistance," I believe. Those are hybrids.

Steve

 

[Smithyard Farm]

Thank you all!! I did come across a website that sold zucchini resistant seeds.. I'll have to continue my research and see what else I can find.

 

[897tgigvib]

Powdery mildew.

It does not only get vegetable garden plants. It can live on things like pea shrub Caraganna. It can even hang out on lawn grass and the weeds in the lawn.

Yes, powdery mildew really takes off when the air is moist, and in shady areas.

Definitely plant resistant varieties and hybrids. The resistance is a dominant trait. Zucchini hybrids that are resistant, most of them, yes, you can save seeds from, but the first year of seeds saved from a hybrid zucchini don't make them your whole zucchini crop, just a few to make sure they are good.

Make sure your other crops are also resistant.

Yes, I would go with a fire on the soil, but also ensure powdery mildew is not lurking in your garden elsewhere, lawn, shrubs, trees, flowers. Zinnias can get it pretty bad, as can sunflowers. Dandelions get it but they are so strong they keep on growing, so they CARRY it.

If you have powdery mildew you may well also have other things such as downy mildew.

Make sure you don't have Beetles. They'll carry it around.

If you burn the soil, burn it hot.

After, see if beneficial soil bacteria is available, along with beneficial fungus. I picked some up and will be doing that soon. My idea is to let good microbes compete with bad microbes. In a few months I'll also be getting garden mushroom innoculant. Not to eat but to grow the soil with.

Yes, a few years back I had powdery mildew. Have not had it since. I went with a multiple attack set on it. Also had it when I lived in Montana one year. Got some of my Cucumbers and Melons.

Don't let the soil splash when you water. Brings the spores right up to the plants, just when things are moist.

Short version: Multi pronged attack.

 

[MontyJ]

If you have an aversion to fungicides, you may try milk on the plant leaves. The ratio is 10:1 water to milk. Spray the mixture on the leaves during late morning, before the heat of the day. It is believed that the pH of the diluted milk inhibits spore germination. It is a common practice of pumpkin growers.

 

[Hal]

I grow 140 types of winter squash and all I do for mildew is the milk trick. You have to get in early and start spraying at the first signs of it and keep it up.
Don't use lite/skim milk make sure to use full cream milk. I also have a gardening contact nearby where I live that uses 10:1 but with goats milk from their own goats and that works well for them too but sadly I don't have goats to try it out cheaply.