powdery mildew on pumpkins

[adrianhumph]

 Hi all,
           My pumpkin foliage seems to be covered in powdery mildew & the leaves seem to be dying down. Is there anything to be done?, or do I just let nature take it`s course?. It seems too early to be cutting the pumpkins, I normally wait until the end of September. Any ideas?
                                                 Adrian.

[adrianhumph]

[Squashfan]

Hi Adrian,
Oh dear.   :P I have some of the mildew myself. But look what I found on t'internet. I was resigned to the mildew myself, but am going to be making up some of this. Baking soda, one ounce per gallon. Now, where to get horticultural oil? Also, they discuss compost teas, also said to be useful. Must go home to the lab and experiment...

http://www.attra.org/attra-pub/bakingsoda.html

[PakChoi]

Re the p. mildew that you already have, spraying the leaves with 1 part milk, 9 parts water is said to work.  I think it does slow the mildew down.  I'm not sure it helps much if there is already a great deal of the mildew.  You'd want to avoid spraying in full sun.

So far as preventing p. mildew goes, or at least significantly delaying it, I've found that covering the ground with water permeable black plastic, of the type used to control weeds, really helps.  You peg it down and plant the plants through cut slots.   The only pumpkin I've got with really bad pm this year is the one without such ground cover.   The cover helps prevent water stress.

Hope this is not telling you stuff you already know!

Finally, even if the leaves look terrible I would hang on as long as poss before you cut the pumpkins.  Last year I lost my nerve when one plant looked completely awful, but I probably could have left them to ripen for another 3 weeks say.  And that was in September.

[Squashfan]

Ooh goody, I'll have to try that too, milk n water. Very useful pakchoi!

[Biscombe]

Same problem here! Milk is good short term but I find it suffocates the leaves if used long term. Your best bet is copper sulphate. I start spraying cukes melons and peas early with C.S, much less mildew this year.

[greenscrump]

I had the pm problem too, I planted my squashes and pumpkins far to close together so not much air circulating wot with watering and the heat in may/june.  Copper sulphate did the trick for me - and if you do it late enough on a still evening most helpful predators will be tucked up for the night  ;)

Y

[adrianhumph]

Hi all,  :D
             Thanks very much for your replies, the bicarb article was very interesting squashfan, thanks for the link. How do you think the black plastic  ground cover works pakchoi? I thought powdery mildew was air borne?
The spraying of bicarb solution or milk seem to be only a preventative measure, so surely it is too late to spray once you have got it?  ??? 

                                                                               Adrian.

[Biscombe]

Go for copper sulphate

[Svea]

i have lots of powedery mildew on my squashes now
it started with one which has only produced one fruit. the plant next to it is slowly getting it nnow but has about 8 or more fruit, so no probs.

i only worry if it gets to my cucumbers, because they will stop producing.

but as it's the same as last year, i just let it be and harvest when the squashes look ripe, despite the mildew. it didnt affect storage time at all.

[Plum]

I have been using barcarbonate of Soda in a spray on Mildew on my cucumbers in the greenhouse. Seems to have cleared the problem

[PakChoi]

             How do you think the black plastic  ground cover works pakchoi? I thought powdery mildew was air borne?
                                                                               Adrian.

Hi, only just seen your note.  The plastic reduces the stress that the plant suffers if its roots become too dry and it is the lack of stress that makes the plant less susceptible to powdery mildew.

[Squashfan]

For some reason, the powdery mildew only seems to be affecting my buttercup squashes, not any of the others. I've decided to take the executive decision (read, lazy woman's/man's) to leave it as it is already September, just about. I'll be careful with the affected vines and not do dopey things like throw them in the compost.  ::) Now I just want to harvest them all but must waaaaaait....

[sweet-pea]

I've got powdery mildew too, mostly on my 'jack be little' pumpkins.  I've cur away the worst affected leaves, I figured that it would allow for more air circulation, and more sun to get in and ripen the fruit.  I do have 2 questions though.

Can I compost the leaves Ive removed, or should I bin them?

Is copper sulphate an organic treatment?

thanks

SP

[Squashfan]

Hi sweetpea,
I think you should keep them separate and not compost them, just to be on the safe side. Unless the composting kills the fungus?  ???