Treating Blunt Pondweed – Aquatic Weed

Q. I would like to know what sort of plant this is that has come up in my dam. It has roots growing in the silt build up. Also would like to know how to remove this, is there something I can put in the dam that will kill it. No stock use this dam, however we have topped this dam up with bore water, would that impact the water/mineral balance to promote the growth?

Answer:

It looks like you have Blunt Pondweed also known scientifically as Potamogeton Ochreatus Raoul which is native to Australia.

This is usually found in stationary and slow-moving water bodies and likes deep silt or gravel. It can spread via seed and these tend to be early December to late January and the mature seeds shed in 3-14 days or via plant fragments. If the silt is organic matter, then you could use Muck Breaker to break this down.

Long term you may want to look at installing an aeration fountain, as this will make the water less appealing to weeds and algae forming.

But to treat it now we would suggest AQ200, which does have a withholding period of 10 days after treatment.

Depending on the aquatic weed density and coverage:1L of AQ200 will treat up to 200,000L of water.
5L of AQ200 will treat up to 1,000,000L (1ML) of water.
20L of AQ200 will treat up to 4,000,000L (4ML) of water.

Apply at a rate of 1 part product to 10 parts town/tank water. Spread the dilution evenly across the water’s surface by using a shower/stream spray or by injecting into the water, focusing directly over the aquatic weeds.

We also recommend if the water to be treated has high turbidity, use an approved flocculant (such as Clear Dam) before application is required.