PLM plans to go forward with weed treatment at Clark Lake tomorrow, Tuesday, May 21.  They will post a notice on lawns along the entire shoreline.  This will be the same posting as mailed to lakefront property owners—and also seen below in previous and this news article.  A “bump-up” treatment may occur in about three weeks.

PLM’s Steve Hanson says favorable conditions are in place.  “The lake now has a strong thermocline.”  A thermocline develops when the top 10 to 20 feet of water is warmer than that which is below it.  That keeps the treatment product in a spot where it can do the most good in ridding the lake of hybrid Eurasian water milfoil. 

Two products listed on the notice are Fluridone and Triclopyr.  Fluridone is expected to take out the HEWM, and the Triclopyr is on the notice in case some HEWM persists at the end of the summer. The manufacturer of the products, SePRO, will cover the cost of the Triclopyr to treat any spots if required.  Copper is also on the notice of no-restriction products, and will be used if any Starry Stonewort is found. Some lakes have been over run by Starry Stonewort.  If it shows up, the best solution is to treat it quickly.  

Steve Hanson puts the restrictions into context as they could be misleading.   “There are actually no irrigation restrictions (except for grass seedlings) at concentrations of 10 ppb (parts per billion) or less. We are targeting 6 ppb.  The grass seedling restriction goes away at 5 ppb.  People will see the 30-day restriction and be concerned understandably.”  He adds, “at the target concentrations there are no irrigation restrictions for established lawns or ornamentals.” Regarding the effect on fish, Steve Hanson notes “There are no restrictions regarding fishing or fish consumption associated with the use of Fluridone.  Fluridone, or any herbicide permitted in Michigan, does not bio-accumulate in the fatty tissue or muscles of fish or other aquatic organisms.”

When invasive weeds showed up in Clark Lake, the community took up the fight.  Lakefront property owners petitioned Columbia Township to established a special assessment district (SAD) so that the hybrid Eurasian water milfoil (HEWM) could be eliminated wherever found in the lake.  Other lakes found that leaving HEWM infestations unchecked clogged their waters-–reducing boating, destroying wildlife habitat and diminishing property values.

Previous treatments at Clark Lake were accomplished through the use of Tricolpyr.  Results were somewhat effective, but fell short of expectations in the judgment of Professional Lake Management (PLM), the company hired to treat the lake and measure results. Through their experience with other lakes, PLM believes Fluridone (brand name, Sonar) will be more effective and plan to use it this season.