Powdery mildew and whiefly/aphid

14 years ago

1st time posting, long time reader. Hopefully somebody can help. everything seemed to be going fine this year for my small plot of summer vegetables. 4 better boy tomatoes, 6 cucumber plants, a couple of yellow squash and a couple zucchini. Been able to harvest plenty out of each plant for the last couple months, and all plants looked relatively healthy. maybe a bit of powdery mildew on the squash, but I just prune the affected leaves and control it.

Then! within the last 3 weeks the cucumbers have needed massive pruning and my tomato plants have just started yellowing and almost dying from the bottom up. Now I know it's normal for "some" yellowing, but I'm losing good foliage at just too fast a rate to hope to sustain my tomatoes into November(it stays warm here til then). The cucumbers have developed foliage loss also due to me having to try to control the powdery mildew also. While the squash varieties tend to be hanging on(although they seem to be the 1st plants to suffer each year.

I've tried, lady bugs,70% neem oil, baking soda and canola oil, and compost tea to try to control(minimize) the damage, but I'm about to give up. Everything was going so well, and then Bam! The only pests I see fly away when I shake the tomato plants are whitefly, although I believe aphids may be present also. I've read that these pests are vectors for fungi and virii. The neem oil is supposed to take care of them though. Says right on the bottle ---fungicide, miticide, controls whiteflies and aphids.

My question is? What works??? They say that prevention is the best method. I agree... But, THE PLANTS WERE DOING RELATIVELY BEAUTIFULLY WITHOUT ANY PESTICIDES UP UNTIL A COUPLE WEEKS AGO!!!

Sorry to yell---this is just driving me nuts though. :(

Any suggestions on brands of better fungicides, pesticides, etc would be appreciated. By the way, we can only water at night here because we are in a drought.

Also, I'm only guessing about the powdery mildew affecting the tomatoes. it's just seems logical since they're right next to everything else. it could very well be TSWV. I wish I was better at diagnoses but I'm just a novice gardener.

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Comments (5)

woohooman San Diego CA zone 10a
Original Author
14 years ago
Also, How would I go about uploading some pics so diagnosis may be easier?
cyrus_gardner
14 years ago
First: They have not found a cure for common cold/flu.
So do not expect those pesticide fungicides eradicate garden plant ills.

Second: To upload pictures you have to go to some image deposit sites. I work with photobucketdotcom.It is free membership.
You upload pictures from your computer over there in you album. Then get an "HTML" link of it (paste it to a blank page on say word pad, label it for yourself..)
Come here write a post and embed the "html" code(s) into your text. Here I just did for an example:
{{gwi:108520}}
When review your post, the image(s) should appear there even before submitting.
...Then go ahead and submit your message.
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Sigh... yet another problem - powdery mildew... please help!
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To directly answer your question on whether you can pick the green fruits from the plant the answer is yes, you can. It comes at a cost though. If the fruits are completely green, they won't ripen off the plant. If there is even a little blushing to them they likely will. There are a number of chemicals that contribute to the overall flavor of the ripe fruit though and removed from the plant, they don't make it to the fruit so there is often some flavor loss when ripening off vine. I am really sorry to hear about your experience, but I would recommend the same thing as Raybo, find a fungicide that is food safe and seems likely to be effective against common foliage pathogens like PM and use them as needed. There are organic and synthetic options, but I don't know what is available to you where you live. It sounds like your one plant is too far gone to be saved, but you might wish to use a fungicide you are comfortable with as a preventative on the ones remaining so they don't suffer the same fate.
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Hi Kurt, Welcome to the forum. I think perhaps you have a double whammy, some kind of pest infestation plus powdery mildew, too. Your first photo looks like the infamous mildew which is a fungus and described as a whitish/grayish frosty-like dusting on the foliage, blossoms and flower stems. It tends to creep over the foliage and doesn't resemble tiny little insects. Foliar mealy bugs look like tiny cottony specks and have a white waxy looking material covering them. They move very slowly and can congregate in the plant axils. If you take a cotton swab dipped in alcohol, the pest will turn a pinkish color if it is a mealy bug. Aphids are plant sucking pests which are green but can also be yellow. They have tubelike structures on each side of the body near the rear end which can be compared to tailpipes! One indication of an aphid infestation is the appearance of honeydew on the foliage. There are also thrips which are a violet grower's nightmare because they are such a nuisance and so difficult to eradicate. They are tiny, smaller than gnats, rather yellowish in color and will fly from plant to plant. If you blow gently on your blossoms(they love those blossoms) and see little pests scurrying around, those are thrips. They also may leave a tell tale corky silverish/brownish scarring on the foliage. In the photo you found on the net there is a mark at 2 o'clock position on the leaf which could indicate some possible thrips damage at sometime. I hope this doesn't muddy the water for you, but hopefully it will help in making an identification. Elaine
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Spider mites are often caused by warm, dry conditions. A good rinsing will help get rid of most of them. You can help keep them away with a humidifier (in heated or air-conditioned spaces) or by keeping a window open. You can also set the pots above trays of water, add gravel to your saucers so that they can hold a little water away from your plants, or put a baking dish of water on the radiator. Produce a mild breeze with a fan; good air circulation will also help with things like powdery mildew. It's important not to overwater; herbs are especially sensitive to this. Let the top inch of soil dry out before watering thoroughly. Make sure all of your pots drain properly (water runs out the bottom when you water them) and never let the plants have "wet feet", in other words don't ever let the pots sit in even a small amount of water. A spray consisting of a teaspoon of baking soda to a quart of water, with a drop or two of dish soap, will help kill powdery mildew. Apply every week or two until the problem goes away. Meanwhile, promptly remove and throw away any branches that become mildewed. Even though I don't have any outdoor growing space in my city apartment, I've been able to rig up a sunny outdoor window box that can grow herbs pretty well. Is this a possibility for you? Neem is "organic" but I wouldn't want to eat it, partly because it smells like a cross between garlic and peanut butter and tastes terrible. Some of those other sprays, even if they're "environmentally friendly," sound even worse. If you can't grow herbs indoors without sprays, I'd suggest getting rid of them. You'll get cleaner, healthier produce at the farmer's market, and there are plenty of houseplants that are more tolerant of the indoor environment.
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woohooman San Diego CA zone 10a
Original Author
14 years ago
ok cyrus. Eradication may be aiming a bit high, but control MUST be possible. There must be some gardeners that have been able to minimize the damage caused to still have a somewhat successful garden. Any suggestions would be welcome. :)

I'll try uploading some pics now. maybe that'll help.

Affected yellow squash 1

{{gwi:108521}}

affected yellow squash 2

{{gwi:108522}}

affected tomato 1

{{gwi:108523}}

affected tomato 2

{{gwi:108524}}

affected tomato 3

{{gwi:108525}}

affected green bean 1

{{gwi:108526}}

affected green bean 2

{{gwi:108527}}

affected cucumber 1

{{gwi:108528}}

affected cucumber 2

{{gwi:108529}}

affected cucumber 3

{{gwi:108530}}
woohooman San Diego CA zone 10a
Original Author
14 years ago
By the way, the cukes and tomato don't look nearly as healthy now.
woohooman San Diego CA zone 10a
Original Author
14 years ago
Thanks for the help cyrus. Now, if anybody else could please help, I MIGHT be happier. lol :)

Should I post the original message to some of the other forums also to get more exposure to a wider audience?

Powdery mildew and whiefly/aphid

Comments (5)

woohooman San Diego CA zone 10a
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Powdery mildew and whiefly/aphid

Comments (5)

woohooman San Diego CA zone 10aOriginal Author

cyrus_gardner

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