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- To: <Aquatic-Plants at actwin_com>
- Subject: Re: Herbicides
- From: Thomas Barr <tcbiii at earthlink_net>
- Date: Mon, 19 May 2003 22:49:53 -0400
- In-reply-to: <200305191127.h4JBRpHJ001500@otter.actwin.com>
- User-agent: Microsoft-Outlook-Express-Macintosh-Edition/5.02.2022
> Read in the local paper that the State DEP may grant the use of Fluridone
> that is choked with hydrilla. They say they will use no more than 20ppb
> (billion). The article stated that Florida spent millions in applying
> Fluridone to keep hydrilla at bay. What do others think of using this on a
> small pond? Will it work?
Yes. Herbicides are popular and often suggested by the Center for Aquatic
Weeds research here. There's a course hereon weed control which they show
you all the ways to kill aquatic weeds. Ha! You thought such a course would
tell you how to grow them huh? No. You need to see the problem here and many
areas and then you understand.
They often use aquatic inverts as guinea pigs and some fish for
applications. There are a number of specific herbicides used these days, I
had a list of them around here, but I simply don't like the principle of
herbicides but the aquatic weed management council will use them. In many
cases they are used.
But you kill the weed, you end up with pea soup/BGA etc.
Which is worse? Clear water with weeds or pea soup?
Lake/pond owners want both but it doesn't work that way.
Then adding the clear water back or another aquatic plant is virtually
impossible to do. A floating plant like Salvinia/Hyacinth may move in after
and require more applications.
> The State is also looking into other means such as
> introducing a number of infertile grass carp to eat it, but the fisheries
> department canned that idea.
Many folks hate the grass carp here. They are triploid/sterile and cannot
reproduce in nature. They are weed lawnmowers. But the end result can be the
same, pea soup.
> How else can evasive plants be kept at bay?
Mechanical removal is done very often.
Lake draw down is a popular method and one that I like.
By drawing down the lake level every few years, it will kill the weeds and
allow for easy removal/export and reduce resuspension of nutrients in
SHALLOW lakes. Deep lakes seldom have weed problems. Also the source of
nutrient inputs should be looked at. Since many lakes that have weed
problems are also shallow, drawn down can really reduce a huge surface area
with little water loss/refill time.
> What about over fertilizing the lake so an algae bloom kills all the plants
> then let it revive on it's own???
Won't work well with hydrillia. It'll simply get worse and then you may get
a nasty algae bloom and fish kills if you added nutrients. That's generally
a bad idea. I don't think anyone would go for that since the nutrients are
likely a cause for plant/algae problem.
Hydrillia is really the "perfect" weed.
It looks very pretty in some places but not to a boater:-) Well, an Air
boater doesn't care:-)
> Won't all the decaying hyrdrilla
> effectively do the same thing as it rots?
Then the fish die from lack of O2 from all the dead algae or weeds. Then you
have a vile stinky dead lake/pond. Algae bloom will cause a huge algae die
off at some point also.
Substrate and wind resuspension of nutrients can have large effects on
Basically it's a fairly complicated problem with no easy solutions but folks
can decide which method and cost is right for them. Often thing backfire but
the folks realize it afterwards when you can't go back.
My vote is for lake drawn down in most cases. Certainly it would be the best
solution and quite cheap for a small pond with a weed issue.
It's a natural process in many lakes and small ponds seasonally.
Removal of the sludge and apply on agricultural fields for fertilizer.
Fish can be removed and added back later after the pond refills.
> Just looking for some other