Pond Boss Forums AQUATIC VEGETATION Controlling unwanted plants Filamentous Lyngbya algae control

HELP!! I have a serious Lyngbya algae problem in a couple of the lakes I manage. I am not a complete believer in the theory that by shading out the bottom, one can control this particular algae. Yes, it seems you may suppress its growth via limiting its photosynthetic capacity, therefore reducing its ability to give off copious amounts of oxygen that is caught in the filaments and rise to the surface, in theory of course. These lakes have numerous shallow areas 3' or less often consisting of 5-15%(conservative estimate) of the lake area. Even with a bloom of 18-24", some light still pentrates at least twice that distance, right??? The phytoplankton absorbs the sunlight and the light scatters until it is absorbed or reflected. There is no 24" line drawn horizontally in the water that light cannot penetrate beneath, right???

The past few years some of the lakes have been neglected due to lack of labor, time, and resources(there is a fertilization program here, has been for the past 30+ years). Lyngbya is the kudzu of the water, if you're not on top of it, it will grow exponentially. There is a great article about it here on pond boss somewhere, Lyngbya wollei.

Interesting observations though, where I see submersed vegetation, Southern naiad mostly I believe, there are little to no Lyngbya problems. Is there any reason why, or is it just coincedence? Nutrient uptake or a matter of it occupying space in the water column, both? Other places without any observable vegetation, Lyngbya is thick from bottom to top, not everywhere though, but it is abundant.

Typical management of Lyngbya here consisted of treatment of surface mats. Anybody who has raked out this algae knows that what you see on the surface is usually just a fraction of what is below. So treating the surface mats was merely a cosmetic treatment because you need to treat the whole, above and below.

So what works and what does not? Anyone have some experience with controlling this in relatively large bodies of water(150+ acre lakes). It is a monumental and notoriously difficult task.

I have a few ideas about possible remediation solutions, via chemical means and possible vegetation introduction into some of the infestations.

Ray, Swampin' in the Filaments

Good question. Grass carp will do little good, and you are correct it is difficult to control in shallow water by shading. I have however had good luck with spot treatments of liquid copper to infested areas. Where is the lake located? I may be able to come by and provide an estimate.

What dosage of liquid copper would you recommend per gallon of water0? I do use Cutrine for treatment of these areas. I thought I was proactive early this year(mid-April) with some granular Cutrine treatments to areas where infestation were bad last year. Come June, BAM, there it was. In a matter of 3 days, it went from no surface mats to surface mats galore. I rake out as much as possible then I go back with the chemical. The spray gun I use is 2.5' long so I stick it down as far as possible, not putting my hand in the water.

The drought over the past 5 years, not including this year, has helped expand the range of Lyngbya because several of the lakes are used for irrigation. This time last year, our biggest lake was 1.5' and eventually made it to 2'. So this may have contributed to further expansion with more sunlight to the new shallows. The rain this year has helped to suppress the surface mats significantly, but it lurks still.

Much more to talk about, but time to go to work.

Ray, Swampin' in the Filaments

I use 4-8 ozs/gallon, but so many other variables involved. Lynngbya could have become chemically resistant like pithophora thus you may try to mix in Reward at 4 0zs/gallon and try that. Of course this makes things much more expensive.