Written by James F. Burns
Biological lake weed control involves introducing a species into the lake to destroy the weeds. At the present, there are only a few biological controls available to the lake manager, and they have their drawbacks. Biological controls are popular because they do not involve chemicals, and are perceived as being “earth friendly”, but this may not in fact be the case.
Problems with biological lake weed control
Remember, that the need for the control is probably because a non native species was introduced into the mix to begin with, introducing another to control the first hardly seems wise.
In cases where the “grass carp” has been introduced into environments other than it’s native habitat, the results have been mixed, ranging from achieving the desired control, to lakes completely devoid of vegetation and almost all other forms of aquatic life. Other issues are escape, which can produce disastrous results downstream, and the potential for the accidental release of non sterile, reproductive capable grass carp into the environment.
There are a few other biological controls available. Basically, these are “bugs” that dine on specific species. The same issues exist with them as with the grass carp.
In general, we do not recommend the use of biological control measures for these reasons.
A better form of biological lake weed control
Natural, native biological control can be used safely by simply following good cultural practices for your pond or lake. This simply involves providing for proper pH, proper fertility, and then allowing nature to do the rest. A properly fertilized pond or lake will produce the right amount of phytoplankton to keep the water tinted, and the weeds at bay, as well as producing healthy fish.
See also: How To Fertilize A Pond Or Lake