Squash plant with mottled leaves

Squash    USA

My squash plants have developed this strange mottling on the leaves. Any ideas what this is? Thanks

Posted by: Maggie Muffins (1 point) Maggie Muffins
Posted: January 31, 2013


Looks like a mosaic virus to me. Maybe cucumber mosaic virus (CMV) or squash mosaic virus (SqMV). Both are transmitted by insects. It’s difficult to tell from the photo but are the leaves wrinkled as well as mottled? CMV will cause this. It’s transmitted by aphids. You should have a look for aphids on your plants and try and wash them off, some warm soapy water will work or you can try the hose. If its SqMV you may see some yellow spots on younger leaves. This virus is transmitted by beetles rather than aphids. Either way, the bad news is that you cannot cure your plant of these viruses and the squash produced by the plants will likely also show symptoms. You can pull up the plants to try and limit the spread or you can try chemical control to kill off any insects. Good luck.

Posted by: Lindsay McMenemy (4 points) Lindsay McMenemy
Posted: January 31, 2013

Maggie Muffins commented,
Yes some of the leaves are wrinkled and not formed properly. Think it might be a virus :-( I'm going to look for aphids of the plants and I think I will remove the plants and think about growing something else. Thanks
over 11 years ago.

Definitely a virus, but which one is nearly impossible to tell without lab testing. Squash mosaic virus is quite common in squash, can be seed transmitted or introduced by cucumber beetles, and can spread plant-to-plant by handling/brushing leaves. It could be CMV as described earlier; others such as watermelon mosaic virus, papaya ringspot virus, or zucchini yellow mosaic virus are also found in cucurbits. Sometimes the fruit have no visible symptoms (not discolored, bumpy, knobby, etc.) - they are safe to eat. Treatment is pretty much the same for these viruses. They can spread to your other cucurbits - cucumbers, melons - so you have to make the choice of keeping or removing the plant(s).

Posted by: Charlie B. (5 points) Charlie B.
Posted: February 28, 2013

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