How to Control Lotus in Australian Dams
Q. I have a large dam full of Lotus plants, fish and tortoises. I need an aqua systemic herbicide to kill the lotus. We used Diquat 200 without success. Lotus are back with a vengence. Can you advise what we can use without harming the fish or tortoises.
ANSWER
Lotus can quickly take over dams, blocking access, reducing water quality, and interfering with pumps and livestock use. Managing it effectively requires the right product and an understanding of how the plant grows.
The Most Effective Treatment Option
The recommended solution for controlling lotus in Australian dams is AQ200 aquatic herbicide. This is a fully registered aquatic herbicide designed specifically for in-water use and is highly effective on broadleaf aquatic weeds like lotus.
While some users try Diquat 200 herbicide, results are often inconsistent. A key difference is that AQ200 is formulated and registered specifically for aquatic environments, allowing it to perform much more effectively in dam conditions.
If Diquat 200 caused some level of die-off, AQ200 will generally deliver a significantly improved result.
Why Lotus Keeps Coming Back
One of the most important things to understand is that no aquatic herbicide provides residual control.
AQ200 works by killing the visible plant, but lotus stores energy in an underground rhizome network within the dam sediment. This means:
- Regrowth is common
- Multiple treatments are usually required
- Full control takes time
Depending on nutrient levels in the water, several applications may be needed to exhaust the plant’s energy reserves.
Supporting Long-Term Control
To slow regrowth and improve long-term results, it’s worth combining herbicide treatment with water quality management strategies:
- Nutrient reduction using Phoslock nutrient binding product
- Adding beneficial bacteria for ponds to break down organic matter
- Using aquatic blue dye to reduce light penetration and slow plant growth
These approaches don’t replace herbicide treatment, but they make a noticeable difference in how quickly lotus returns.
How to Apply AQ200
Correct application is essential for achieving the best results. This includes using the right rate, ensuring good coverage, and treating at the appropriate growth stage.
For a step-by-step demonstration, watch this video guide
Where to Buy
AQ200 is available to order online
