Zucchini plants died last year...trying to prevent that this year

eli2009May 11, 2009

Last year we planted a couple zucchini plants which at first grew beautifully and even started growing the zucchinis but when the vegetables were a couple inches long they suddently stopped growing and the leaves turned yellowy and wilted and eventually the whole plant died. We did have some sort of mold/bacteria i think on the plant at the end which is presumably what killed it. the leaves had these white spots on them which is how i "diagnosed the problem" In the beginning the plants did not have this problem...

Anyway I remember reading somewhere there is a "recipe" to make that you can spray on the plants that will protect them from this mold/fungus type disease. Does anyone know what the recipe is?


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Hi Eli-
I just did a quick google search, and someone has apparently done some research for you:

Wagner Bettiol, a scientist from Brazil, found that weekly sprays of milk controlled powdery mildew in zucchini just as effectively as synthetic fungicides such as fenarimol or benomyl. Not only was milk found to be effective at controlling the disease, it also acted as a foliar fertilizer, boosting the plant's immune system. In his experiments with zucchini plants, Bettiol found that a weekly spray of milk at a concentration of at least 10% (1 part milk to 9 parts water) significantly reduced the severity of powdery mildew infection on the plants by 90%.

Paul James, master gardener and host of Gardening by the Yard says he used a milk-and-water solution (1 cup of milk with 9 cups of water) to control powdery mildew on cucumbers twice a week and his powdery mildew problem disappear. Milk has a germicidal effect (it kills the fungal spores) & it also appears to stimulate plants in such a way that they become more resistant to the disease. "In recent university tests, the milk and water spray was found to be more effective than the two most popular synthetic fungicides on the market today".

Any kind of milk can be used, but Paul Crisp (University of Adelaide, Australia), recommends using dry-milk powder15 grams for every liter of water. So far, he finds, this formulation appears to work on all surface mildews. It's best to use milk on sunny days because they need the sun's light to kick-start their mildicidal action.

David Bruer, formerly a professor of enology (winemaking), likes to alternate using different organic agents such as mik: (emulsified canola oil and bicarbonate once a week and then moving to a spray of whey and then seaweed extract the next cycle) because they appear to offer different modes of action in killing mildew. He is reluctant to use one organic fungicide exclusively saying: "That might make it easy for the mildew to develop resistance to control."*

Those black lessions sound like Choanephora Wet Rot. "The organism (Choanephora cucurbitarum) attacks summer squash as the blossoms wilt and quickly spreads down the fruit. A black mold, resembling tiny pinheads, appears on the necrotic area. Spores are spread by insects and splashing water. This disease is common under high moisture conditions". http://www.uga.edu/vegetable/squash.html
Chaonephora fruit rot is soilborne disease which rots the young fruit. "It can be controlled with a combination of treatments using foliar sprays of chlorothalonil, raised beds and open foliage varieties. This allows air movement to dry the soil and the foliage. Also, avoid planting squash on heavy, poorly- drained soils. Apply fungicides during wet periods". http://plantanswers.tamu.edu/vegetables/...
After the crop has been harvested, all remaining debris should be removed and destroyed. A 3-year crop rotation should be implemented as the bacterium can persist in the soil for up to a year and a half. Handle fruit carefully to minimize injury prior to curing since infection also occurs post-harvest. (Another site recommended a 4 year crop rotation for fungal disease: anrcatalog.ucdavis.edu/pdf/7245.pdf)

I haven't found anything yet for Botrytis, Bacterial Wilt, or Yellow Mosaic yet for you...will keep looking.

    Bookmark   May 11, 2009 at 11:51AM
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I'm still researching, and found this interesting tidbit on bacterial Wilt from a Cornell University study: It seems that there is less chance of a plant developing this if it is transplanted at 5+ leaf stage. I am a winter-sower, and start all my veggies in milk jugs early so I have starts to plant out when the weather gets warm enough (rather than waiting til Memorial Day and planting a seed, so now I'm a couple weeks ahead of the game doing it WS style)

Anyway, I found that note really interesting, and will definitely wait longer to plant out my zucchini this year (started them in their milk jugs this past weekend).

    Bookmark   May 11, 2009 at 12:02PM
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bella_trix(z6b SE PA)

If your plants died from powdery mildew, regular spraying of milk at 1:2 or 1:4 dilution with water can control the disease well.

However, I would be suspicious that powdery mildew killed the plant that quickly. They can usually survive it until fall, unless you have a very damp summer. Where are you located? Please update your location to include at least your state, but preferably a nearby city location and your USDA zone. For a wilting zucchini plant, my first guess would be Squash Vine Borers. Type Squash Vine Borer or SVB in the search field and you will find many discussions on this pest.

mmqchdygg - I would not wait until a zucchini plant has five leaves to transplant it. They are very sensitive about having their roots disturbed and transplanting can kill them. It is best to grow them in peat/newspaper pots so the roots are undisturbed when transplanting or transplant them not later than 2 weeks after sprouting.


    Bookmark   May 11, 2009 at 12:17PM
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why thank you!!! I will try it. Its interesting though, I just googled it and came across this on ehow.com

"Although powdery mildew looks horrible, it causes little harm to the plant. Harvest your zucchini and enjoy the fruits of your labor."
which is interesting because i thought it killed my plants and my friend thought it killed her plants too...

    Bookmark   May 11, 2009 at 12:25PM
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bella trix:

my location is Baltimore, MD but maybe i was overwatering? how much water should zucchini plants get? how often?

I didn't notice any of the "symptoms" suggested for the SVB but then again I didnt' really look for it since I assumed it was the mildew that killed it...

as far ast he milk...how often do you suggest spraying is the 1x a week enough?

    Bookmark   May 11, 2009 at 12:46PM
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Sounds like late blight to me. Try finding a product named Green Cure. I used it during a early blight problem I had last year on my Zukes and it worked great. Also This stuff helps prevent and gets rid of any mildew or fungus infestations!

    Bookmark   May 12, 2009 at 12:42PM
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I'm going to be trying a 0.75% baking soda ("bicarbonate", mentioned above) solution on my powdery mildew this year. I've read some published papers on it that seemed very encouraging. And it's a lot cheaper, more environmentally friendly, and less spoilage-prone than milk ;) The recommendation for it is one application weekly. It kills powdery mildew on contact, but doesn't stick around.

I agree that powdery mildew generally doesn't kill plants like that. Looks awful, but the plants generally soldier on (kind of like peach leaf curl in that respect). I'd second the squash vine borer theory. Nasty buggers. I've got my BT handy ;)

    Bookmark   May 12, 2009 at 2:50PM
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I just started searching for photos of powdery mildew. I think it's attacked my squash. Would it also show up on my cukes?

I clipped off most of the leaves on the squash and the leaves that looked questionable on the cukes (so far just a few), sealed them up and tossed in trash. That includes a few eggs I found that I couldn't figure out if they were Good Eggs or Bad Eggs.

If anyone knows where I can find photos of various plant ailments it would be helpful. I thought it was fungus at first (I gather not the same as mildew) and spraying milk or sodium bicarb seems much more environmentally friendly.

Although I can grow perennials like no one's business, this is my first year growing veggies on any scale so very much a beginner on this.

    Bookmark   June 16, 2009 at 8:56PM
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I have a similar problem with my zucchini and cucumbers. My zucchini have gotten white spots on the leaves and some of them had died. I kept getting the fruit and as a new gardener, I didn't worry about it. After a week or two I noticed that most of the branches were dying and when I lifted some, the stem broke just above the ground. It was rotted through. All three of my plants have died and I removed them all from the garden. We have had a wet summer and I may have over watered them, though my soil drains pretty well.

Next, my neighbor's cucumbers (which are separated from my garden by a link fence) have all withered and died. I am now noticing spots on my cucumber leaves, some have even become holes, and the vines are beginning to wither. Is there anything I can do to prevent further damage or what can I do to prevent this problem next year? Should I spray milk on them?

    Bookmark   August 18, 2009 at 6:43PM
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mike_marietta_sc_z8a(z8a upstate SC)

The dying squash plant and the stem breaking just above the ground sounds like the results of squash borer damage. They often enter the stem near its base and burrow/eat their way up the inside of the stem, eventually killing the plant.

    Bookmark   August 19, 2009 at 9:12AM
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