Powdery Mildew on my pumpkins

[lupitt]

New to VG and new to gardening so hello!

I have six lovely pumpkin plants, all growing really well with about 2 pumpkins per plant. They've got to the size of honeydew melons and stopped growing.

At the same time they've become absolutely covered with powdery mildew. I've been careful to water them frequently but not too much, and only in the morning, at the base of the plant, not the leaves etc.

Our soil is very heavy clay and also the plants are too close together - I know now that it helps to read up on these things before planting out!!! Could either of these two things have contributed?

What I absolutely want to avoid is digging up the plants as the pumpkins look like they could do really well. I think it may be too late though as every leaf on three of the plants are white all over.

Any ideas?

Many thanks.

Lucy

[Lesley Jay]

Hi Lucy, you are quite right that planting the pumpkins too close together has contributed to the powdery mildew. I have read that a mix of one part skimmed milk and 9 parts water sprayed on the plants can help with powdery mildew. I think the idea is to start spraying at the first sign of the disease but it might be worth a try. You can also remove some leaves which gives the pumpkins a better chance of ripening before the first frost. The spores will over winter on dead plant tissue ready to infect plants next spring so be sure to clear away all of the plants at the end of the season. I would bin or burn them rather than composting. Good luck!

[kiwi]

I too have a powdery mildew problem starting on my pumpkin plant, with only a few days to go until autumn and a few of the pumpkins look to be full sized already, I'm wondering if I need to treat the plant, or is it OK to let it die off already. The first frost in my area in New Zealand would be mid April.

[Lesley Jay]

Hi Kiwi, I would leave the plant untreated as you are so near to harvesting the pumpkins but you could remove the infected leaves and then either burn them or put them in the rubbish bin as the disease will over winter on the dead plant ready to infect your plants next year.

[kiwi]

Thanks Lesley,
Another question if i may- I've noticed quite a few of the young pumpkins grow to the size of a tennis ball then died off. Any ideas why? I've given the plant plenty of nitrogen rich plant food & kept it reasonably well watered.
thanks.

[Lesley Jay]

Hi Kiwi, if there are alot of pumpkins this might just be down to the pumpkin vine naturally shedding excessive fruit or maybe they weren't fully pollinated. With pumpkins it does happen. Some growers restrict the number of pumpkins per vine which channels the plants energy into giving all the fruit a chance to grow to maturity. With the feed a nitrogen rich plant food is good at the beginning as this promotes vine and leaf growth but once the fruit is set change to a potassium rich feed which promotes fruit growth. I hope that helps a bit.

[kiwi]

Hi Lesley, I had a good look around last night and found 3 full sized fruit and one tennis ball sized fruit. It appears the plant is starting to die off as some of the older leaves have turned yellow. The plant is a volunteer that popped up in my compost pile and I decided to let it take over. I hope the powdery mildew doesn't ruin my compost now. I'll take care to remove the plant and burn it once the pumpkins are ripe.