A presentation on the performance of 3 varieties of parsley grown with and without mulch. Study done by Mr Anthony Phillips and presented at the National Research Conference, 2009. (See it in pdf format) 

 see the pdf document

Click on photo to see the presentation

Please note that this presentation is not intended to imply that fabric mulch should not be used when growing parsley. The point that is being made is that higher soil moisture /poor areation encourages the develoment of the disease and that some varieties are more susceptible than others in high soil moisture. If irrigation is being used in the dry season it would be necessary to monitor the soil moisture status.