A few weeks ago we had a duckweed bloom in two of our lakes literally overnight?
Of course this was just before labor day. Fortunately we had some aquatic herbicide Cutter in the chemical storage room. Cutter went down at 1 lb/ per surface acre tank mixed with a surfacent at 100 oz/ acre. The products were sprayed with a spray gun (large droplet size to prevent drifting) covering the entire lake surface. The next day there was no change and I was a bit upset, but on the third day the duckweed was 1/2 gone and the fourth day so long duckweed!
Below are some before and after pictures.
September 2nd Labor day