Yellowing Cucumber leaves

Athenian(USDA 10B/Sunset 22)June 16, 2012

My cucumber plants seem thriving and producing lots of blossoms and fruit however I am worried about the leaves. The leaves all seem to have pinhole sized thin areas which can be seen when looking up toward the sun. They gradually get bigger then the leaves yellow and dry out.

Is there something that can be done about this or am I destined for a short cucumber season?



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howelbama(7 NJ)

you have to keep the fruits picked, if you let them ripen on the plant, the plant will start to shut down as it senses its lifecycle is complete. it could also be a nutrient issue though...

    Bookmark   June 16, 2012 at 6:00PM
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Athenian(USDA 10B/Sunset 22)

The plants just started producing; I've only had 2 cucumbers off one and one off another. I have lots of blossoms and a few more fruit forming on the other plants. I'm afraid that if this keeps up though, I won't keep getting cucumbers.

    Bookmark   June 16, 2012 at 6:13PM
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howelbama(7 NJ)

if you can post some pics that would help.

    Bookmark   June 16, 2012 at 6:30PM
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Athenian(USDA 10B/Sunset 22)

Okay, I don't know how clearly this will show it but I have 3 shots.

The first shows what most of the leaves look like when I hold them up to the sun.

The second shows a larger leaf that has started to deteriorate

And here's one that is pretty well gone

    Bookmark   June 16, 2012 at 8:57PM
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howelbama(7 NJ)

The stippling on the leaves looks like you may have spider mites. They will sap the energy from a plant and cause it to yellow by basically sucking out the chlorophyll. If you take a piece of white paper and hold it under the foliage, then give the leaves a good shake, it will knock some on to the paper. Then look at the paper closely, if you see little tiny dots that appear to be moving on the paper, then you've got mites. You can also sometimes detec them on the paper if you smear you finger across it and it leaves stains from the squished mites behind. Sometimes you can also detect them by a fine webbing strewn about th plant.

    Bookmark   June 16, 2012 at 9:23PM
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that is what is called Cercospora leaf spot. use a copper fungacide on it once a week until the temp turn hot over 90 degrees. when the temp turn hot it should slow down and stop. i get it every year and i try to buy cucumber seeds that are resistant to leaf spot or at least tolerant.

    Bookmark   June 16, 2012 at 10:44PM
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howelbama(7 NJ)

Some of the larger spots might be cercospora though I thought the spots had darker rings aroun the edges of the spots with cercospora?

What I'm referring to is all the tiny little yellow dots everywhere, the stippling effect, that looks like spider mite damage to me.

    Bookmark   June 16, 2012 at 11:01PM
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looks like spider mite damage. i do agree with howelbama about getting paper and giving the leaf a good shake as the mites are pretty small.

    Bookmark   June 17, 2012 at 12:22AM
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Athenian(USDA 10B/Sunset 22)

Okay, I'll check for mites in the morning.

If that's whats wrong, should I spray them with a soap mixture? There are 8 plants in a 5ft cage so it's going to be hard to get them sprayed with a hand sprayer. I was thinking of trying a hose end sprayer set to a teaspoon of Murphy's Oil Soap per gallon.

I've seen conflicting advice about the need to rinse plants after a soap spray.

    Bookmark   June 17, 2012 at 3:22AM
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some people just use a garden hose others use neem oil with water solution. i have had spider mites myself. i took a 2 gallon spray bottle and hit them with the neem oil. if you do use neem oil do not use it on a day when the temps are going to be over 90. it will fry your plants since it is oil based. then after a about week hit them with the water hose to make sure you get the rest.
neem oil is a really good product to have. it works on small insects as well as funguses.

    Bookmark   June 17, 2012 at 8:53AM
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Athenian(USDA 10B/Sunset 22)

I went out to do the white paper test and really didn't see much. After shaking several leaves, I ended up with one tiny beige bug and one darker one. I went ahead and sprayed anyway though since I figured it couldn't do any harm -- 1t. Murphy's Oil Soap to 1 gallon. I'll wash them all off with plain water in a few days and try to be patient.

I decided to go the Murphy's Oil Soap route because I always have it in the cleaning cabinet. I've been reading a bit about Neem oil and will see about getting some for future use.

Thank you for the advice.

    Bookmark   June 17, 2012 at 12:49PM
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howelbama(7 NJ)

athena, they are microscopic. so you wont really see them on the paper, but sometimes you can detect their movement. if you smear your finger across the paper, you will usually notice streaks ob the paper from the ones you squished lol...

the soap should do the trick, you may have to reapply every few days, and make sure you get the bottom of tge leaves as that is where they hide out.

    Bookmark   June 17, 2012 at 2:44PM
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jean001a(Portland OR 7b)

the tiny spots that are everywhere are the stomatoes, not mite stippling.

    Bookmark   June 17, 2012 at 6:39PM
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I have a container garden this year and it has been great. No pests, worms, etc. About a week ago I put cypress chips in the pots to help with moisture control. Today I noticed my cukes have yellow spots on the leaves and aphids were on one of my squash plants. could the cypress chips be causing some of these problems. It has been doing so good up till now. Help!!!!!

    Bookmark   June 20, 2012 at 12:44AM
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Athenian(USDA 10B/Sunset 22)

I did the soap spray on my plants and things have gone from worrying to much worse. My plants continue to grow but entire leaves are turning yellow -- not in spots but the whole leaf. This is especially bad with smaller, newer leaves but it is happening to larger leaves that were previously all green.

What should I be thinking about now?


    Bookmark   June 28, 2012 at 1:26PM
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rnewste(8b NorCal)

I am seeing similar leaf issues, but mostly on the lower leaves. The top half of the plants look healthy and green:

I do see White Flies on the undersides of some leaves, but this is not affecting fruit production at all. I've resisted spraying with Take Down Garden Spray to date, but may apply it if the insects get worse.


    Bookmark   June 28, 2012 at 1:44PM
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