Mildew on pumpkins

Mine were fine too, until about a fortnight ago! I have just cut off the worst affected leaves and exposed the fruits to the sun to help ripen them. I've also cut back any long trailing stems to the last 'decent' fruit to focus energy on the main ones. I have already 'harvested' one fruit (I accidentally broke it off!) - it is slightly smaller than I would like but was perfectly okay for roasting. I'll keep feeding and watering the rest and hopefully they'll keep growing until I'm ready for them! Oh, the squash I 'harvested' was an Uchiki Kuri, but I have 'Polar Bear' and 'Crown Prince' too - I treated them all the same and they are still growing okay :-)

I've been reading that the mildew - whilst it can look bad, doesn't do the fruits any harm (courgettes that I have grown in the past at home didn't seem to be affected, so I guess winter squash will be similar). This years squashes are still growing well and more healthier looking leaves have started to replace the ones I removed (See pic) You can leave the squashes to mature until the leaves die back, but I'm always impatient to try them before that happens! Also read that the taste will deepen the longer the fruits are left on the vine - so thats my next experiment - if it looks big enough and looks ripe enough, give it a try 

You might try a treatment with fungicidal properties.

Neem is an organic option, if you are looking for that. A little research online might be good to verify if Neem works on mildew.  Other than that, I am not sure what fungicides are available there.