Getting rid of duckweed

Hi all.

Anyone here had any experience in getting rid of duckweed on a large scale?
I think that is what it is, I know it's not water cabbage (or lettuce?).
We have it in one of our dams at work, on a very large scale. Long story
short, it has made it's way to all dams on a small scale, including the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it as
it's too small for the roundup to stay on it in the water. If it does, then
my guess is that any bits missed will easily spread quicker than the rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade, but we
haven't tried that as it can be found under shade from some of the rushes in
the dams.
The ducks have spread it already, and while we can filter it from the front
dam (though it's probably too late) it won't stop ducks or birds spreading
it.
I have noticed it on the banks of the dam where water level has dropped it
appeared to have died. We can drain all dams bar the front one, but it's
something we want to avoid due to lack of rain.

Thanks for any advice.

On Sun, 9 May 2004 15:40:03 +1000, "Andrew G"
wrote:

Hi all.

Anyone here had any experience in getting rid of duckweed on a large scale?
I think that is what it is, I know it's not water cabbage (or lettuce?).
We have it in one of our dams at work, on a very large scale. Long story
short, it has made it's way to all dams on a small scale, including the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it as
it's too small for the roundup to stay on it in the water. If it does, then
my guess is that any bits missed will easily spread quicker than the rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade, but we
haven't tried that as it can be found under shade from some of the rushes in
the dams.
The ducks have spread it already, and while we can filter it from the front
dam (though it's probably too late) it won't stop ducks or birds spreading
it.
I have noticed it on the banks of the dam where water level has dropped it
appeared to have died. We can drain all dams bar the front one, but it's
something we want to avoid due to lack of rain.

The same hassle has hit the Hawkesbury River in Sydney recently. They are using
a $1 million machine to scoop the stuff out of the water.

put a sign on the road saying $5-/bag. with a note telling people to pay at
the house. Watch it disappear lol.
sorry I couldn't help.

"Andrew G" wrote in message
...
Hi all.

Anyone here had any experience in getting rid of duckweed on a large
scale?
I think that is what it is, I know it's not water cabbage (or lettuce?).
We have it in one of our dams at work, on a very large scale. Long story
short, it has made it's way to all dams on a small scale, including the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I
have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it as
it's too small for the roundup to stay on it in the water. If it does,
then
my guess is that any bits missed will easily spread quicker than the rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade, but
we
haven't tried that as it can be found under shade from some of the rushes
in
the dams.
The ducks have spread it already, and while we can filter it from the
front
dam (though it's probably too late) it won't stop ducks or birds spreading
it.
I have noticed it on the banks of the dam where water level has dropped it
appeared to have died. We can drain all dams bar the front one, but it's
something we want to avoid due to lack of rain.

Thanks for any advice.

Oh, I don't think I'd break it up... I don't think it matters, and if you
break it up, it may float to the surface.
I'll try to find out for you.
Jade.



"Andrew G" wrote in message
...

"Jade" Jade_at_Jaywings_dot_com wrote in message
u...
Throw a bale of hay in. (this is not a joke, just try it)
:0)
Jade

Would this work on a large scale? I'm talking one dam would be close to
the
size of a football field.
Do the bales have to be broken up first and spread over it?
We could try it, we have hay at work :-)
Getting in some "natural" chemical to try tomorrow, but somehow I don't
think it will work.
cheers
Andrew

Throw a bale of hay in. (this is not a joke, just try it)
:0)
Jade


"Andrew G" wrote in message
...
Hi all.

Anyone here had any experience in getting rid of duckweed on a large
scale?
I think that is what it is, I know it's not water cabbage (or lettuce?).
We have it in one of our dams at work, on a very large scale. Long story
short, it has made it's way to all dams on a small scale, including the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I
have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it as
it's too small for the roundup to stay on it in the water. If it does,
then
my guess is that any bits missed will easily spread quicker than the rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade, but
we
haven't tried that as it can be found under shade from some of the rushes
in
the dams.
The ducks have spread it already, and while we can filter it from the
front
dam (though it's probably too late) it won't stop ducks or birds spreading
it.
I have noticed it on the banks of the dam where water level has dropped it
appeared to have died. We can drain all dams bar the front one, but it's
something we want to avoid due to lack of rain.

Thanks for any advice.

"Jade" Jade_at_Jaywings_dot_com wrote in message
u...
Throw a bale of hay in. (this is not a joke, just try it)
:0)
Jade

Would this work on a large scale? I'm talking one dam would be close to the
size of a football field.
Do the bales have to be broken up first and spread over it?
We could try it, we have hay at work :-)
Getting in some "natural" chemical to try tomorrow, but somehow I don't
think it will work.
cheers
Andrew

I cant remember where I heard of this... I think the University of
Queensland uses it in their lakes to control excess algae, and I think it
helps keep the plants down too. You might need multiple bales, do you have a
smaller pond to try it on first?

Anyway, I think it's worth a shot, and if it works, you've got a cheap
solution to your problem. If not, you've not wasted much money at all.

I don't think that the hay was broken up. I think it works by taking the
nutrients and oxygen out of the water, because the microbes use it all up
whilst breaking the hay down. Even if it doesn't remove the duckweed, your
lake will be algae free.

Good luck.
Jade.

"Andrew G" wrote in message
...

"Jade" Jade_at_Jaywings_dot_com wrote in message
u...
Throw a bale of hay in. (this is not a joke, just try it)
:0)
Jade

Would this work on a large scale? I'm talking one dam would be close to
the
size of a football field.
Do the bales have to be broken up first and spread over it?
We could try it, we have hay at work :-)
Getting in some "natural" chemical to try tomorrow, but somehow I don't
think it will work.
cheers
Andrew

"Jade" Jade_at_Jaywings_dot_com wrote in message
u...
Oh, I don't think I'd break it up... I don't think it matters, and if you
break it up, it may float to the surface.
I'll try to find out for you.
Jade.

Thanks very much for the help.
Well the chemical we got to try today was "water clear", or "clear water",
something along those lines. It's active constiutent(sp?) is orange oil,
kinda smells like citronella. Designed purposely for 3 particular water
weeds (salvinia, red "something, and forget the other weed), I don't think
duckweed is on it, but apparently some courses in Sydney have used it on
duckweed.
However there is one problem. It says do not spray on thick mats of weed
where the water can't be seen, and in one dam it has got like this.
We will try the hay in 2 small ponds, but I don't think it will be too good
in the large dams. The smallest dam we have is about 2.5megalitre cap and
they are all nearly full.
Thanks again

Perhaps a long time solution would be to introduce some vegetarian
fish. I can't help with the name at this stage but they do exist. They
wouldn't be any good getting rid of large amounts of duckweed, just as a
control. I'll ask around for details of suitable fish and post back with
more information if I get any.
DD

Andrew G wrote:
Hi all.

Anyone here had any experience in getting rid of duckweed on a large scale?
I think that is what it is, I know it's not water cabbage (or lettuce?).
We have it in one of our dams at work, on a very large scale. Long story
short, it has made it's way to all dams on a small scale, including the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it as
it's too small for the roundup to stay on it in the water. If it does, then
my guess is that any bits missed will easily spread quicker than the rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade, but we
haven't tried that as it can be found under shade from some of the rushes in
the dams.
The ducks have spread it already, and while we can filter it from the front
dam (though it's probably too late) it won't stop ducks or birds spreading
it.
I have noticed it on the banks of the dam where water level has dropped it
appeared to have died. We can drain all dams bar the front one, but it's
something we want to avoid due to lack of rain.

Thanks for any advice.

Hi
Shading will work, but needs to be fairly solid cover.

The questions to ask are
Why do you want to get rid of it anyway?
Does it cause a problem? May reduce evaporation and warming of the dam,
thus inversion layer.
Ducks will continue to bring it back, so even if killed off, it may return
ASAP.

Robert

"DD" wrote in message
...
Perhaps a long time solution would be to introduce some vegetarian
fish. I can't help with the name at this stage but they do exist. They
wouldn't be any good getting rid of large amounts of duckweed, just as a
control. I'll ask around for details of suitable fish and post back with
more information if I get any.
DD

Andrew G wrote:
Hi all.

Anyone here had any experience in getting rid of duckweed on a large
scale?
I think that is what it is, I know it's not water cabbage (or lettuce?).
We have it in one of our dams at work, on a very large scale. Long story
short, it has made it's way to all dams on a small scale, including the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I
have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it
as
it's too small for the roundup to stay on it in the water. If it does,
then
my guess is that any bits missed will easily spread quicker than the
rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small
area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade, but
we
haven't tried that as it can be found under shade from some of the
rushes in
the dams.
The ducks have spread it already, and while we can filter it from the
front
dam (though it's probably too late) it won't stop ducks or birds
spreading
it.
I have noticed it on the banks of the dam where water level has dropped
it
appeared to have died. We can drain all dams bar the front one, but it's
something we want to avoid due to lack of rain.

Thanks for any advice.

"Aspley Nursery" wrote in message
...
Hi
Shading will work, but needs to be fairly solid cover.

Hi there,
The questions to ask are
Why do you want to get rid of it anyway?

We don't think it will clog the pumps if the level gets low enough, but it's
still a possibility.
Biggest problem is if the pumps do take it up and manages to squeeze it out
the sprinklers, then it will be sprayed over the fairways (not a big
problem), but worse, it will be sprayed onto the greens. That I imagine will
promote fungal diseases due to moist grass, but more so it will cover the
grass and it will have to be removed from them everytime the sprinklers come
on. To much hassle.

Does it cause a problem?
See above.
May reduce evaporation and warming of the dam,
thus inversion layer.

That may do that, though dam temps here on the mid north coast don't suffer
too much of variation. I should say due to the climate, and the capacity of
the dam from which the water is pumped.
Ducks will continue to bring it back, so even if killed off, it may return

Yeah, that's the problem. Well we got it reduced to a size to where it's
manageable, from scooping, and the water clear chemical.

Cheers
Andrew
ASAP.

Robert

"DD" wrote in message
...
Perhaps a long time solution would be to introduce some vegetarian
fish. I can't help with the name at this stage but they do exist. They
wouldn't be any good getting rid of large amounts of duckweed, just as a
control. I'll ask around for details of suitable fish and post back with
more information if I get any.
DD

Andrew G wrote:
Hi all.

Anyone here had any experience in getting rid of duckweed on a large
scale?
I think that is what it is, I know it's not water cabbage (or
lettuce?).
We have it in one of our dams at work, on a very large scale. Long
story
short, it has made it's way to all dams on a small scale, including
the
front dam where water is pumped from.
We have tried scooping it, and even barracading it off, to no avail. I
have
tried Roundup Biactive (or equivalent), but it doesn't seem to hurt it
as
it's too small for the roundup to stay on it in the water. If it does,
then
my guess is that any bits missed will easily spread quicker than the
rate
sprayed stuff dies.
Copper sulfate did have an effect, but it was only tested in a small
area,
as it seems to affect water pH.
Someone suggested black plastic over it as it doesn't grow in shade,
but
we
haven't tried that as it can be found under shade from some of the
rushes in
the dams.
The ducks have spread it already, and while we can filter it from the
front
dam (though it's probably too late) it won't stop ducks or birds
spreading
it.
I have noticed it on the banks of the dam where water level has
dropped
it
appeared to have died. We can drain all dams bar the front one, but
it's
something we want to avoid due to lack of rain.

Thanks for any advice.