spider like web covered with red spots on my old cucumber plants

5 years ago

I grow cucumbers in my greenhouse. These plants have been growing well since February, so they are old, and suffering in parts from downy mildew. But still producing well. However, today I noticed at the top of the plants a spiderlike webbing covered with reddish spots. Not sure what it was, so I destroyed the plant, as it is getting time anyway to move on to winter plants. I am wondering if anyone knows what this might be? This is an image of the spider like web covering a leaf dead from mildew.

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Comments (5)

peggyhamill
Original Author
5 years ago
PS - I live in Taos, New Mexico....
Skybird - z5, Denver, Colorado
5 years ago
last modified: 5 years ago

I've never seen them that bad--I didn't even know they could get that bad!--but could it be red spider mites? Take a loop or a strong magnifying glass to see if you can identify individual mites.

https://commons.wikimedia.org/wiki/File:Red_spider_mite_(Tetranychus_urticae).jpg

https://duckduckgo.com/?q=red+spider+mites&t=h_&iar=images&iax=images&ia=images
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peggyhamill
Original Author
5 years ago
Oh my gosh. Thanks so much Skybird. That seems definitely to be what this is!!! I have been gardening for 45 years, but mostly in the state of Maine, and I have never seen this little critter. But I got out my magnifying glass, and that is definitely what it is. I see that keeping the plants moist might help, as well as to use a soap spray - which I will try. Do you have any other ideas for control?? Thanks again, Peggy
Skybird - z5, Denver, Colorado
5 years ago
last modified: 5 years ago

Glad that helped, Peggy!

I only ever get "regular" spider mites here in Denver, but many, many, many years ago I grew up in Illinois and it seemed like the red ones were on everything back there, so when I saw the pics I though that might be what it was!

My "go to" cure for just about anything in the garden is Palmolive (or any "basic"--not Dawn) DW soap in water in a pressure sprayer--and it works well on mites--and aphids. But you need to get the under sides of the leaves--and EVERYWHERE--to try to get rid of them since they live in the "tiniest places!" With as bad as they are, and since you've had those plants for so long, I recommend just starting over with new plants! And since you have them that bad, I recommend spraying anything and everything in the greenhouse--or, at least anywhere near the cukes, since they've very likely spread to other things too. If you do decide to start new ones I recommend removing the old plants and spraying the soil and everything that was anywhere near the old plants and then waiting a bit to start the new plants--maybe spray a couple/few times with a few days between spraying just to be sure you're giving your new plants a "safe environment" to grow in.

Also keep an eye out for "regular" mites, which are much harder to spot since they're not red! The sooner you see a problem and spray--or do something about it--the easier it will be to fix.

I envy you having a greenhouse! Happy growing!

Skybird

P.S. Forgot this! Don't spray when the plants are in the sun! Wait till late in the day, or very early so they can dry off well before the sun hits them.
peggyhamill
Original Author
5 years ago
Skybird, you have been so very helpful. I have removed all of the plants that I can see that are infected. Interestingly, the infections only manifested at the very tops of the plants - where it is the hottest and driest. I did read that these mite prefer hot and dry. Most of the greenhouse is quite humid due to the watering that is necessary - but not way up there, I guess. And I will follow your advice about spraying all surrounding plants as well as the soil. I will watch carefully for further infestation.!!! Best to you, and hope that you and your family are well. And thanks again.