I have filmentous algae. Directions on cutrine plus say to measure area of algae and then depth to come up with acre foot and then it gives you a chart to figure how much to mix with water.

I don't understand this?? The algae is floating around on the surface of the water. At any given time it may be where the water is one ft deep and an hour later it may be blown over to where the water is five feet deep, so I don't understand why water depth is a consideration.

Is there an amount that I can just mix with a gallon of water and spray the algae. I.e. Mix a quart with a gallon, etc.? As I said I do not understand why I should figure water depth since algae is just floating on the surface of the water. Also, when you spray you are supposed to just use droplets and not a fine spray right.

Thanks

I think Cutrine-Plus liquid is not really designed as a surface spray which is why most all the instructions are based on treating FA growing up from the water column and in the water column such as green water bloom.

For floating FA in the past, others have suggested the liquid be diluted 9 parts water to 1 part Cutrine-Plus as a tank spray. Try this 9:1 dilution as a test spray first on an isolated patch of your floating FA. Watch this treatment area for 2-3 days for signs of algae discoloring and dying. If it does not show symptoms of dying, try mixing it a little 'hotter' at a 5:1 or 6:1 dilution for a larger spot spray test. Try this mixture and report back so other readers can benefit from your experiences. The gallon goes 'further' if the 9:1 mix works for your particular FA. Many FA species vary in their tolerance to copper algaecides. Always - the less copper algaecide that is needed is best practice.

Remember- all that biomass that you kill: 1. will die, decompose, consume oxygen, and most importantly recycle all its bound nutrients back into the pond to grow the next session or bloom of FA; and
2. removing as much of the FA as possible before treatment deduces the amount of copper added to the pond and
3. Removing FA removes more nutrients from the pond slowing the aging or eutrophication of the pond, it also reduces the amount of the next bloom of FA and
4 killing the FA with an algaecide also kills myrids if not billions of tiny invertebrates including zooplankton that is the food buffet among the FA for small fish.

I experimented with Cutrine Plus liquid over the weekend. I read numerous directions which stated that 1 gallon of CP should be diluted with "at least" 9 gallons of water....I diluted it with 14 gallons in a tank sprayer I took out on the boat. I didn't make any more complicated calculations than that because I was basically spot treating.

The FA I sprayed was all on the surface and blown by the wind to the north side of the pond.

I will be interested to see if that level of dilution was effective when I head out to the pond this weekend. That should be enough time to see at least some results. I will keep you posted. BM61

Different types of FA react differently to algaecides.

spirogyra filamentous algae vs. pithophora filamentous algae comes to mind immediately.....

The first disappears if you look at it with a grouchy face, the 2nd needs a nuclear attack.

I bet it turns it brown and sinks it. I think you will be happy with results.

I dilute CUTRINE PLUS 9 to one with a surfactant FOR FA WHEN THERE IS NO DUCKWEEK. Works great, but the floating FA turns white before sinking, not brown. If you happen to catch a rain a couple of days later then everything on the surface will be gone. When I need to spray for FA and duckweed I use the same 9 to 1 on Diquat and spray them both together. Surfactant is a key ingredient, I use cidekick, and if not available just plain old pink dish washing detergent. I REVISED THIS TO MAKE IT MORE CLEAR (AT LEAST MORE CLEAR TO ME). THE ALL CAPS WORDS ARE THE REVISION

We had one hell of a rain three days after I sprayed the FA with Cutrine Plus last Sunday. Heading up there this afternoon for the dove opener and looking forward to seeing some results. It would be great if the surface was clear as Bing suggests it might be.

Does the Diquat/surfactant work well for submerged weeds like sago pondweed (or any submerged weed)? Can you simply stick the sprayer wand under the surface of the water (i.e., a foot or two below the surface) as you troll over the nuisance weeds and have success? I have never tried that technique.

Have you used that combo for subsurface weeds Bing? Thanks. BM61

I have had very good success eradicating duckweed and FA in my 4 acre pond in NC with the following mixed in a 15 gal sprayer: 20 oz 37% diquat, 60 oz Cutrine plus and 4 oz nonionic surfactant. After a lot of research I found a study on the efficacy of diquat plus copper. I will post a link to the study as soon as I can find it again. Basically, you add the diquat in the 15 gal of water, mix well, then add cutrine plus, mix well and lastly add the surfactant. Spray the surface at a rate of about 15 gallons per acre. Better results are obtained on sunny days when temps are in the 80's. You have to spray the mixture within an hour's time of mixing because the diquat and copper will chemically bind and become ineffective.

I never spray Diquat under water. Surface contact only. I occasionally spray Cutrine Plus underwater, around pilings, etc, Also, see my post earlier where I have made additional clarification (ALL IN CAPS)

UPDATE: hunted the evening for the dove opener in a sunflower plot next to the 6.5 acre BOW I treated with Cutrine Plus (diluted 1 gal of CP with 14 gallons of water)last Sunday.

There was not much FA left on the surface....90% of the pond was clean as a whistle. We had a 2 inch rain on Wednesday (in about 45 minutes) so I am sure that helped plus the low temperature has been in the upper 50s the last 3 nights.

I will continue to experiment with CP next year but the FA is starting to slowly disappear or at least stop growing for this season it seems.

Ptt: I will try your diquat/CP mixture next spring and test it out on our BOWs. We are always looking to improve our FA killing success. Thanks for everyone's advice. Have a great Labor Day weekend.

Oh yeah...and the dove hunting was good but not great. We had to be patient. Not a lot flying. That plus our sunflower plots leave a little bit to be desired this year. Lots of trouble with water hemp. BM61.