We've recently launched a new site for showing what fungi are considered "widely prevalent" by different state extension specialists and mycologists. The list will be used by APHIS-PPQ to develop a list of fungal plant pathogens that are common in each state to help expedite the permitting process for obtaining research isolates. You can see the new site at www.prevalentfungi.org.
More information, including criteria for expedited permits, is available at: http://www.aphis.usda.gov/plant_health/permits/organism/wpp/index.shtml
When the fungal list is completed by APHIS it will be posted on this website.