The Maryland Department of Agriculture (MDA) is the regulatory agency in Maryland for pesticide applicator certification. (Extension may share information or help train, but is not regulatory.) We recommend you contact the Pesticide Regulation Section of the MDA for guidance about certification status, and Extension's horticulture conferences are often free if no cost is listed in a registration page (it largely depends on the venue and whether food will be served). If there is no link to online registration information, a point-of-contact is listed:
Pesticide Certifications (the table for commercial applicators is below all the private applicator listings). Conferences are also listed in the seasonal IPM Alert reports (for landscape/nursery but also for cut flower/greenhouse, often on the final pages of each report issue) and accessible through the linked page. Most take place in the winter, but there might be some that can be used for CEUs by the June deadline.

Miri