What is the white shiny thing on my zucchini plants?

Squash    NYC

Does anybody know what is causing the shiny white discoration on my zucchini plants? How can I get rid of it? Can the plants be save? I cut off a lot of discolored leaves, but the new ones eventually turns shiny white, leather like. Please help.

Posted by: michelle (5 points) michelle
Posted: July 13, 2014


It is tricky to make a diagnosis from a photo, but one possibility is squash silverleaf disorder, a physiological problem caused by feeding of some whitefly species. When immature silverleaf whiteflies feed on squash leaves, their saliva introduces toxins that trigger these symptoms. It only takes a few whiteflies to induce the disorder - check the underside of some leaves to see if you have an infestation. The plants can recover with treatment.

Here are a couple of websites that describe the problem in more detail and possible treatments :

Posted by: Charlie B. (2 points) Charlie B.
Posted: July 14, 2014

I think Charlie B may be right if the whiteflies or whitefly eggs/nymphs are there. If not though, another possibility is that they are experiencing sun bleaching. If they were recently transplanted from partial sun to full sun (especially on a rooftop) then they might be having a bad reaction to too much sun. To avoid this in the future, you can acclimate your plants to more and more sun over a few days. This often happens if you start your plants inside under lights and then move them outdoors.

Either way though, don't cut off the leaves that are showing the silvering. They are still functional and contributing something to photosynthesis, even if it is not as much as usual.

Posted by: Kerry Mauck (58 points) Kerry Mauck
Posted: July 14, 2014

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