History of Aquatic Herbicides to Treat Lake Weeds
The use of aquatic herbicides to treat lake weeds has been around since the late 1940’s with discovery of 2, 4-D, (the same stuff you use to kill dandelions in your yard). Actually, the use of chemicals to treat lake weeds goes back to the 1880’s when copper and sea salt were used.
But with the advent of 2, 4-D, the race was on to create more aquatic herbicides. By the 1970’s, up to 500 new herbicides and pesticides were being produced each year. Concern over the proliferation of all these chemicals led to the creation of the US Environmental Protection Agency, to regulate them.
After new, more stringent testing, many of these aquatic herbicides proved to be extremely toxic, not only to lake weeds, but to fish, animals and people as well. You may recall DDT was a very effective pesticide, but very bad for the environment. Interestingly, although DDT was banned in 1972, production continued in the US until 1985 for use in other countries.
Though aquatic herbicides can control lake weeds, large scale usage and public concerns over environmental and human health issues prompted regulatory agencies to closely monitor aquatic herbicides.
As a result, many of the aquatic herbicides of the past 60 years have been banned. Today there are less than 20 aquatic herbicides approved to treat lake weeds. Of those, only about 10 are used regularly.
Concern over lake weed “resistance” remains an issue. The longer aquatic herbicides are used, the more resistant lake weeds may become, creating the need for stronger applications to control lake weed growth. Stronger applications can result not only in increased expense, but in greater toxicity as well, until reaching a point where aquatic herbicides are no longer a viable option.
In the future, other methods such as benthic barriers, (lake mats) biological, mechanical and physical removal must be used to control the overgrowth of lake weeds.