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Cucumber Fungus (Downy Mildew) - Need Help

ios94 Jul 31, 2010 07:45 AM

Is it safe to eat the few fruit that are on left on the vines.

It seems my cucumber plants have this fungus.


I've been harvesting so many cucumbers the last month and all of a sudden the leaves are infected. Probably all the rain we had a week ago.

Now the fruit are not growing properly (the ones that are remaining are kind of stumpy), my main question is, is it safe to eat the few fruit that are on left on the vines or should I toss them in the garbage.

I'm going to try and spray the leaves with a baking soda mixture although it may be too late.


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    morwen Aug 1, 2010 08:31 AM

    Yes the fruit is safe to eat although the flavor may be affected. It probably is the result of no rain and then lots of rain. Even during a perfect weather stretch you can get mildews and fungus if you water the plants from above. Watering under the leaves, keeping the vegetation as dry as possible will help prevent the stuff. Not entirely, but it helps a lot.

    4 Replies
    1. re: morwen
      ios94 Aug 1, 2010 10:42 AM

      Yup, exactly what we've had in Montreal and probably the rest of the northeast. No rain in early July then buckets on and off in mid to late July. Whenever I watered I definitely watered the roots only.

      I tried the baking soda mixture yesterday, I'll let you know how it goes.

      Does anyone know if hope is lost or can the vines rejuvenate themselves? The vines seems to have slowed down but the most recent leaves don't seem to have been affected yet and there are some fresh flowers.

      1. re: ios94
        morwen Aug 1, 2010 02:01 PM

        Last year we had downy mildew on our various squash vines. They put out new vines, leaves and fruit but the mildew continued to spread. The squash were fine, the plants were just not pretty. We didn't do anything to them though so I'm really interested in hearing how the baking soda works. This year we lost vines and fruit to squash borers and beetles. Absolutely beautiful one day, decimated the next and crawling with beetles. The scallop squash have been somewhat resistant so far but I think the only thing saving them is we're handpicking the egg cases off them daily.

        1. re: morwen
          ios94 Aug 13, 2010 07:26 AM

          It seems the mildew slowed down but the vines have pretty much stopped growing. I really can't say if this is due to the first attack of mildew or if other factors were involved. i.e. I'm in a new development and the soil is very rocky and "clayey" so I really didn't redo my entire garden bed, I dug up a few inches and got as many rocks out as possible but at the end of the day the gardening soil I used was only put into holes about 2-3 feet in diameter. It could just be that the roots are having a hard time.

          My plants did produce quite a lot of cucumbers before the mildew kicked in so maybe it just reached the end of it's life although I don't think this is the main cause.

          It still is bearing a few healthy fruit but others that are sprouting are looking "yellowish-brownish".

          1. re: morwen
            Eldon Kreider Aug 13, 2010 02:59 PM

            I would be cautious about using baking soda (sodium bicarbonate) as a fungicide due to leaf damage from the spray. Potassium bicarbonate is much safer. Analogy is potassium chloride as fertilizer versus the destruction caused by similar concentrations of sodium chloride. Insecticidal soaps are make using potassium hydroxide rather than sodium hydroxide used in most soaps partly because of the lower chance of foliage damage and partly because potassium soaps tend to be liquid at room temperature.

            The bicarbonate fungicides are unusual because they have some curative action but very little if any preventive action. Most fungicides used on vegetables are strictly preventive. A good mode of attack is to use potassium bicarbonate in the morning and follow with a different fungicide in the late afternoon. Alternating two preventive fungicides with different modes of action is a good idea.

      2. plantsondeck Aug 14, 2010 09:56 AM

        Although my garden's seen better days (heat, drought, bugs) this was the first year I haven't had to deal with mildew woes. I used a milk/baking soda/soap spray; here's the recipe: http://plantsondeck.com/2010/06/10/mi...

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