We just got home from a 10 day vacation and found our cucumber leaves turning yellow! Cucumbers are plentiful, and we've gotten a perfect amount of rain while we were gone. Does anyone know why the leaves are turning yellow? Do they need fertilizer? MiracleGro??
Here are a couple close up pics....
Are they crispy yellow or floppy yellow? How hot did it get while you were away? How about wind? Did they get any supplemental watering?
Turtles, they're not floppy or crispy. They seem normal, just yellowing. Our daughter lives right across the road from us and she said we got the perfect amount of gentle rain while we were gone, and that there was no need to water the garden. I kept an eye on radar while we were gone and I could see the rain over our farm. No bad winds either.
I guess I'll just use some miracle gro on them and see if they respond. It can't hurt them I guess....
It looks like cucurbit downy mildew. The leaves develop a spotty yellow.
Laurel, is there a fix for downy mildew??
The leaves have now started going from yellow to crispy brown. :(
I still have lots of blossoms though.
Growing resistant varieties along with a program of broad range fungicides are used either in advance of the problem or with signs of early symptoms. Still no sure fire guarantee. Your leaf damage is too extensive to be fixable. The current cukes won't be effected but lack of chlorophyll production and shading as the leaves die, along with the disease itself, will cause fruit problems. The fruit might be bitter or corky or taste okay but be misshapen. This is when you see funky golf ball cukes.
There are differences between downy and powdery mildew. Downy favors cooler temperatures and wet weather. Powdery likes heat and high humidity (that's us). UNC tracks outbreaks in commercial fields because it's a huge crop concern for commercial growers. Apparently MI is being hit hard this year as several areas are labeled as present to epidemic. Though we are not showing a problem in GA, we've had an unseasonably cool, wet summer in the mountains. My Long Pie pumpkins have been hit and some of the butternuts. It seems to be hit and miss with my garden though the problem exists where I grew susceptible plants last year. I'll rotate out of there next year. I tend to grow what I like and maybe not pay enough attention to possible challenges. :)
This is anecdotal, not scientific...winter squashes run so fast that it seems I've gained some control over newer growth. Where they start off as a group of leaves in the patch they are looking bad but as they branch out and away from each other, spill down the hillside with improved air circulation, the new growth looks okay. However, I see a smaller harvest in store.
This message was edited Aug 14, 2014 8:08 PM
Thanks for all your help, Laurel! You've been a huge help, with me just learning about this problem. We're harvesting the cucumbers we can as soon as we can. Some of my production is only for seed. Is it safe to assume the seed is still good???
We have had the strangest summer, after last winter's "polar vortex". Today the high was 70 degrees, and now at 11pm it's 55 degrees with a low of 44 tonight.....in the middle of August!!!
Then when you add in all the rain we've gotten, it does not surprise me that Michigan is getting hit with downy mildew. :(
One university's page on downy mildew provided info on what to use on organic crops (http://www.carolinafarmstewards.org/wp-content/uploads/2012/12/4-ATTRA-Downy-Mildew-Control-in-Cucurbits.pdf ). This is the product, below. I may order some just to have it on hand, should other plants in my garden start having fungal problems! :)
http://www.arbico-organics.com/product/2434/plant-fungal-disease?gclid=Cj0KEQjwmayfBRDo25CR9un4hvEBEiQAv9fBbeJNK-AaK0CNhgZWHgGF1kRBlpMOlYKRGNcuodH5RgYaAm2z8P8HAQ
