Zucchini Disease- help?

Discussion in 'Gardening & Plant Propagation' started by Timedess, Jun 17, 2005.

  1. Timedess

    Timedess Guest

    Our zucchini has been pretty nice so far this year. I'm curious, though- the leaves were patterend with silvery spots as they got bigger. I tried to see if it was powdery mildew by rubbing it- the spots seemed part of the plant, rather than something external, that could be rubbed off. Are there zucchini varieties that have silvery spots on the leaves? Or were these plants already diseased? We bought these at Lowe's this spring- they're "Bonnie's" and do not list a particular variety on the label.

    Well, now the two are wilting fast, and overnight (literally) half the leaves have turned into some sort of crumpled-up yellow mess. The fruits, which looked soooo good yesterday (I was going to pick some of them today) are also turning yellow. What is this? Is it a danger to the yellow squash and pumpkins that I have growing nearby? I also have dill, blueberries, tomatoes, and peppers and cucumbers in close proximity. Is my entire garden in danger? I'm considering pulling up the zucchini plants and tossing them into the trash (as poopsed to the compost bin), even the remaining good one, as I'm pretty certain that it, too, will show this disease or whatever it is before too long.

    The rest of the garden is looking pretty good so far, and I'd rather give up on the zucchini, and the yellow squash too if necessary, than have the possibility of whatever this is spreading and destroying everything/anything else.
  2. Jimmy Mack

    Jimmy Mack Well-Known Member

    May 7, 2004
    Timedess, this might help...

    "Squash Silverleaf


    Silverleaf symptoms appear first at the leaf veins, as opposed to interveinal silvering that is genetically controlled, and is common in many zucchini cultivars. Symptoms develop in the interveinal area so that the entire upper leaf surface is distinctively silver (Figure 1). Symptoms do not occur on the leaf underside.

    Silverleaf symptoms have been observed on very young plants with only three true leaves, on plants in later vegetative stages, and on plants during fruit production. All or some leaves on a plant may be affected. In severe cases, plants are stunted and fruit production is restricted. The disorder may appear on plants scattered through a field, on plants on one side of a field, or on all of the plants in a field.

    Some observations suggest that symptoms disappear occasionally, and plants resume normal growth. However, silvering is permanent in any given leaf in which it occurs, but it is developmentally reversible. Normal plants can develop new silvered growth and plants having silver leaves can develop new green growth.

    Fruit symptoms are not noticeable in cases of mild leaf silvering, however, when leaf silvering is severe, fruit color is lighter than normal. Yellow summer squash is very pale-colored, zucchini squash is light-green to yellowish-green, acorn squash is mottled green to yellow, and golden acorn squash is white (Figures 2 and 3). Yield reductions and poor fruit quality are usually associated with leaf silvering.

    Silverleaf symptoms have been noted on all types of squash (Table 1) but have not been observed in muskmelon, cucumber, or watermelon."

    from: http://www.imok.ufl.edu/LIV/groups/cultural/physio/vcfs1.htm

  3. OD

    OD Well-Known Member

    May 25, 2004
    I have a Roly Poly squash plant that has the silver spots on the leaves, but it doesn't seem to be hurting the plant. Actually, it is two plants growing together & only one has the spots. Your plant may have died from some kind of wilt or it could have been borers.
    Here is a picture of mine. Is this what yours looked like?
  4. Timedess

    Timedess Guest

    Yes, that's what it looks like, all right! Dh went out and trimmed off all the wilted/yellowed leaves; I am now thinking of just pulling up all the plants (there are 6 growing in pairs), because right across the path I have some sugar pie pumpkins growing, and I don't want them affected by it. :( I am appalled that all 8 plants I bought from Lowe's were affected by this, almost immediately after I planted them. Could it have been soemthing in our soil, or something they were already affected with, and it just didn't show up until they were planted and growing some more? I'm pretty disappointed about it; however, I'm much more protective of my pumpkins than the squashes (I can get squashes very reasonably at the farmer's market, but have been wanting to grow my own pumpkins for years!). Thanks for the link, info, and pic!
  5. Jimmy Mack

    Jimmy Mack Well-Known Member

    May 7, 2004
    OD's roly poly squash is the picture of health. I wish my squash were doing so well! I think the picture was shown to illustrate that some varieties have variegated leaves, or some type of pattern on the leaf. OD's plant does not have the sliverleaf disease.

    What variety are you growing Timedess?

    "Silverleaf symptoms appear first at the leaf veins, as opposed to interveinal silvering that is genetically controlled, and is common in many zucchini cultivars."

    Are your "spots" first appearing on the veins. Check out the pattern of the distribution in OD's picture. The spots are not grouped along the veins which indicates they are not caused by silverleaf disease.

    For '05 my garden features a 1949 AAS Winner - Casserta Zucchini Squash. This is another variety that has "silvery spots" on it, and its supposed to grow that way.

    You say "half the leaves have turned into some sort of crumpled-up yellow mess". That's not good. Some yellowing and dropping of the bottom leaves is normal. Half of the plant turning yellow means something is wrong. The pattern of the leaf drop like whether leaves start dropping from the top or bottom of the plants can tell alot. As well as how the "silvery spots" develop on the leaves, as mentioned previously.

    Be sure not to overwater. Lots of fungus type outbreaks are caused by overwatering. Also in most climates its best not to put your garden to bed wet. So either water in the mornings are early evenings/late afternoon.

    Best of Luck!
  6. Timedess

    Timedess Guest

    :( Oh, well- I see what you were saying, about WHERE the silver spots come on now, JimmyMack. But we just pulled them up this morning. :( I wasn't wanting to take chances. I've got some sort of something going on with my tomatoes, too- but that's another post. I'm getting very frustrated this year! :waa: I have no idea what variety they were- I could not find a variety name ont he tag when we bought the plants. I tell you, it is the LAST time I'll buy "unknown" from the hardware store, though! :mad: I think this year is a year full of "lasts" for me! :haha: