Does anyone have an idea of what can cause dry white leaves on parsley plants and what I can do to stop it?
Here is a link that might be useful: Photo
I'd suspect it was burned by the sun or chemicals (like a fertilizer).
If the plant was indoors recently and just planted outside, the hot sun can burn leaves. Plants, just like us who have been inside for long winters, become more accustomed to sun in time and won't burn in time.