This map was made by ACT in late summer, 2007.  The places marked "A", "B", and "C" and where the Pirates put down mats that summer. 

 

The areas shown in green are where dense Milfoil beds were detected in September.   The areas in yellow are where light coverage was present.  The areas in silver are where dense or light beds were expected, but none was found.

 

Clearly something happened to the Milfoil in Lake Luzerne in 2007.  The Pirates, and all the volunteers who helped them, put forth a wonderful effort but can't claim credit for most of the improvement.  Something much more than the benthic mats was involved.

 

ACT contacted both Larry Eichler from Darrin Fresh Water Institute and Bob Johnson from Cornell University to ask their opinions. 

 

Neither had a definitive answer.  Apparently Milfoil "crashes" periodically, perhaps due to a change in water chemistry, a natural surge in weevils, an exhaustion of bottom nutrients, etc. 

 

There is some anecdotal indication that weevils may have been the cause.  In the south end of the lake in particular, Milfoil appeared to be present, but spread out on the bottom as if the stems had been broken.  This is one of the conditions expected from weevil activity, but it could not be examined and measured scientifically.

 

In any event, Eichler and Johnson agree that within a year or so of such a crash, Milfoil usually comes roaring back!