If you have used Lake Management in the past to treat your shoreline, you likely received a letter from them informing you they will no longer be serving Crystal Lake.  Homeowners looking to replace this service are encouraged to seek a company that is DNR-approved.
The CLIA Board is aware of two potential companies who can service Crystal Lake individual shore line weeds this summer.  These are: Midwest Aqua Care and Lake Restoration.
The CLIA Board wants to be crystal clear that the mention of these companies in no way represents an official endorsement of them or their services.  Homeowners should conduct their own careful study of which company they wish to employ.
The DNR vendor lists can be found here 
(At the bottom of the DNR page  is a PDF for  commercial pesticide control.)