Not exactly sure what "silverleaf" is, but my summer squash usually end up with some powdery mildew that sort of makes the leaves silver. Easy organic cure is 2 tablespoon of BAKING SODA in a gallon of water. Mix to dissolve and spray the leaves until thoroughly wet on the entire plant. Weekly applications, or after rain / irrigation should keep it in check. The baking soda does something to the pH of the mildew. Good luck!

I too have suffered through whitefly silverleaf. It attacked my pumpkin, winter squash, patty pan aquash, and zucchini. After reading it donesn't harm the quality of the fruit, I left it but I now feel I made a mistake as the flys and disease spread like wildfire (even though they wer not visible to me unless I really shook the plant). I finally pulled all diseased plants and am spraying something in that area that attacks all stages of the whitefly at once. I read somewhere that insecticidal soap only attacks 2 of the 4 stages of whitefly. The other two stages are supposedly susceptible to Neem or pyrethrin sprays.

Since I garden in containers only, I am spraying the ground area (the place the containers sit) with a non-insecticidal, non-Neem, Non Pyrethrins spray. Just an FYI - I sprayed with Garlic spray, pepper spray, orange essence spray and none of these sprays worked to eliminate the whitefly. However, my garden always had a distinct smell.

We humans (gardeners in partiular)sometimes percive insects as having the same smell/ taste senses as we do.
So if we don't like pepper, garlic tomaco,.. staste and smell then bugs won't like it either. Some may do , most may not.

Thanks all,

If I decide to grow squash next year, then I'll have to try some of these things out. I was hoping the new leaves would grow in nice and green but they don't. They turn silver right away. I'll keep watering the plants and see if they can grow out of it.

I have the same problem. New leaves are growing in silver! Also i have noticed some flowers are getting black fuzzy mold, before they mature. i think its a downy mildew problem instead of a whitefly problem, although i have both:(

This seems to be complained about every month or so here. Many squash have a natural silvering in the leaves, It's part of the plant, and is called varigation. Here's the last one.

https://www.houzz.com/discussions/6281297/powdery-mildew-or-variegated-leaf-pattern#n=4