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from "DerekW" contains these
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Are we confusing duckweed Lemna minor with algal blooms and filamentous
algae which barley straw does control.

I take it that's a question? I would guess that the OP would know the
difference.

We had huge problems on the shoot with a pond being covered with a thick
carpet of duckweed and despite a serious effort to remove it during which
we scooped off around 60-80 kilos a week over a month or more it came back
within days.

Arable land nearby? That growth could be due to fertilisers leaching
into the pond.

This year 2008 it had all but disappeared the only difference being the
introduction of proper pondweed the previous year which has finally taken
hold and colonised the margins it could be the heavy rain or the weed
reducing the nutrient level or even overspray when our farmer applied
herbicide (unlikely he's extremely careful about when he sprays and
the pond
is about 30 yds from the nearest cultivated area) We do get a lot of duck
but in the covered years they didn't make an impression on the carpet and
they positively avoided the pond we have few frogs ( heron activity) and no
fish.

I'm told - but haven't tried it - that duckweed is very nutritious and
makes good a soup ingredient. The odd water snail amongst it should
provide a little body...

Common Koi and Grass Carp do eat duckweed and I did a little
research and
found freshwater shrimp also do .

The shrimp will eat anything, but you'd need a lot of them.

I'll ask the local head keeper about the condition of his flight ponds.

--
Rusty
Growing old is mandatory; growing up is optional.
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