Great Info. I am in a private club and we have an 18 acre lake stocked well with LMB and BG. We have tried several types of chemicals to get rid if the duckweed without success. The past couple of years we have used Diuron and it has done an amazing job. Now we're being told it is illegal to use this stuff so I am trying to detemine if it is really illegal as the individuals indicating such are not lawyers, etc... need some advise as to how we can get rid of this awful duckweed. it has now covered the entire lake.