Shasta Daisey Problem

I am having a problem with my Leucanthemum superbum, Shasta Daisy “Becky.” For the past two or three years right after bloom the stems began to yellow and they rotted near the crown. Last fall, I decided it might be disease in the soil, so I found a different spot in the border and purchased new plants. This week I had the same exact symptoms. Any ideas?

Crown rot ; caused by? Is what you describe ,,

Thank you Juruh7. Do you recommend a solution for crown rot?

I've lost a few this year to crown rot, Fennel and some others to wet weather , soggy soil , I don't know if there is , Like others though .. it has to do with drainage , or the few bugs that can cause it ..