I'm ASSUMING I should just scrap any foliage I remove from my garden that has powdery mildew. But I just wanted to make sure. If I were to add this to my compost... would it contaminate my soil? Or is PM a disease that is NOT spread by the dirt? I've not heard of it being spread by dirt - as I understand it develops when leaves don't have ample air/time/space to dry out quickly when they get wet.

Should I, or should I not compost the leaves??

They're going in a separate pile for now, as I'd rather err on the side of caution. But if anyone knows that it IS ok to add them to the compost, it would definitely boost my "greens" as I haven't needed to cut the grass in months due to our hot weather.

Great question! I'll be watching for answers also, since nearly all of my squashes have been hit lately. We had, uncharacteristically, 4.24" of rain last week.

I don't compost anything with any type of disease. Why take the chance?

I put it all in the compost and don't worry about it. I figure by the time it comes out the other end it's morphed completely. Ask different gardeners and you'll get differnt answers.

The spores that cause Powdery Mildew will not survive a normal composting process so you can compost any plants affected by PM with no qualms. There is some research that indicates that when diseased plant tissue is composted immunities to those plant diseases are developed in the compost that are passed along to the soil and then the plants so they are then better able to resist future diseases of the same type.

Thanks!

I've been composting powdery mildew foliage for years & haven't found that it increases (or decreases) the possibility of having it again. It's definitely a disease that's weather specific. If we have a relatively dry & less humid summer (yeah, right - lol), I have less or no powdery mildew, regardless of the composition of my compost.

Now for the Botrytis that attacks my peonies? That I definitely do NOT compost. I bag it & put it out with the trash. And since I began doing so, regardless of the weather, I've seen a definite reduction of outbreaks. Same goes for Blackspot on my roses. For both of those, I highly recommend bagging & trashing, not composting.

good info here!

I got some PW on cucubits and I was composting it but was only going to use that for non-cucubits thought I ready somewhere that they are different for the different families.

Looks like I should just compost well and forget about it.

Thanks everyone. I thought I'd heard somewhere you CAN compost it - as it's simply a weather-caused ailment... but wanted to be sure!

I haven't heard of the boosted immunity by composting certain diseased plants... though it kind of makes sense.

Thanks again! Happy fall clean-up to all!

Powdery Mildew is not just some "weather-caused" problem, although it does need certain weather conditions for the spores to come alive on the plant. Powdery Mildew is often a problem in greenhouses where the soil is new every growing season and everything the plants grow in and one is sterilized, because the spores come in on the wind. PM is most often a larger problem on plants that are under stress, plants that are not strong and healthy, so work on your soil to make it good and healthy so it will grow plants that are strong and healthy and better able to withstand those various disease pathogens.

Oh good grief - here we go again. You know what Kimm1? Just substitute "environment-caused" for "weather-caused" ailment. Will that satisfy you? Because regardless of whether warm, humid conditions are inside a greenhouse or out in the garden, those conditions DO promote the appearance & severity of Powdery Mildew. I can have the richest, healthiest soil & the most robust Lilacs on the planet, but if we have a hot, humid summer versus a somewhat drier one (like we had this year, thank God), I will have Powdery Mildew on those Lilacs.

Luckily, it's a disease that, while rendering the affected plant somewhat unsightly, won't normally kill it. The plants return robustly next year ready to fight & pray for friendlier weather.

I'll definitely be laying out soaker hose or a drip system on all my squash next year as the PM didn't really hit until I had to start using the sprinkler frequently during our hot, muggy weather. Then it came on full throttle.

Funny thing is... my watermelon & canteloupe vines, which did NOT get hit by the sprinkler, thanks to the foliage from a nearby tree, but are only about 12ft away from the PM infestation, were not affected at all. So I'm convinced the sprinkler is to blame. Unfortunately, my option was to let everything die or spend 3 hours watering each plant by hand at the base.

So yes... soaker hose goes in next year EARLY... while the plants are still in that "this can't possibly become a monster" stage.

BreezyGardener, weather is one, small part of the environment.

quote:

Originally posted by Jen's Garden:
I'll definitely be laying out soaker hose or a drip system on all my squash next year as the PM didn't really hit until I had to start using the sprinkler frequently during our hot, muggy weather. Then it came on full throttle.

Kimm1 does have a point here.

If you needed to water your plants (with a sprinkler, or by other means of irrigation) it was because of dry and hot weather, and that in itself is a condition which causes stress to zucchini plants. So, as soon as plants are stressed, they become targets of disease and pests.

This year I had the most beautiful, bountiful zucchini plants ever, so strong and healthy they survived the attacks of squash bugs and squash vine borers! That never happened to me before, but the point is: it rained almost everyday for two months, and squash plants truly benefit from frequents soaks.

Things changed as soon as the daily rain ceased, when I had to start using soaker hoses.
A couple of weeks into the dry spell and powdery mildew starts to show, followed by cucumber beetles and other pests. My zucchini plants took a hit, and 3 of them died.

But I feel successful, nonetheless, because the remaining 5 survived and are still going. I've been working at improving the soil for 15 years, and I am happy I'm actually beginning to see the results.

I'm trying to figure out why I had no SVB, squash bugs or cucumber beetles. I saw one squash bug in the soil early this spring and squished him and that was it!
After 3 days of rain was when I got PM and none before. It is funny because on the pumpkins it is worse on the leaves facing north/east. Zucs are great because if they get a little fertilizer boost the PM leaves will die and get crunchy and new green shoots will jut off the main stalk and put out fruit. Then you can clean up the yucky bits and have decent looking plants again.