Aquatic Weed Control

What are the ecological impacts of aquatic weeds? 

Aquatic weeds pose dangers for Australia’s plants and ecosystems. When left to proliferate, they can: 

• Hinder water flow
• Degrade water quality by reducing oxygen levels
• Impede water access for animals 
• Outcompete native plants for resources, reducing biodiversity
• Disrupt fish spawning grounds 

How to control aquatic weeds

Integrated weed management is the most effective approach to controlling aquatic weeds. It combines these strategies to manage weed populations: 

• • Physical control is the manual removal of weeds through hand-pulling or using mechanical harvesters. While this is adequate for small infestations, physical methods are labour-intensive and may inadvertently damage aquatic plants and habitats if done incorrectly. 

• Environmental control means altering the environment to make it less conducive to weed growth. Strategies include changing water levels, improving water flow, and managing nutrient inputs to limit favourable conditions. 

• Chemical control involves managing larger or more stubborn infestations using herbicides. When selecting herbicides, it’s crucial to consider their efficacy against target weeds, their impact on non-target species, and regulatory guidelines around their use. 

The best herbicides for aquatic weed control 

The two most popular, effective herbicides for aquatic weed management are glyphosate and non-residual diquat. 

Aquatic-safe (biactive) glyphosate 

This is a broad-spectrum herbicide that targets various aquatic weeds. While effective, its use must be managed carefully due to potential risks to non-target species. 

Non-residual diquat

This fast-acting herbicide is used to control floating and emergent weeds. Diquat will likely provide immediate results, but it may require multiple applications for long-term management. 

Is using herbicides around aquatic species safe? 

A concern when using herbicides to control aquatic weeds is the safety of fish and other aquatic species like frogs. Regulatory agencies such as the Australian Pesticides and Veterinary Medicines Authority (APVMA) evaluate the ecological impact of herbicides prior to approval.

To minimise the impact on neighbouring aquatic species, consider the following: 

• • Aquatic toxicity: Most herbicides include guidelines to ensure safe use around aquatic life, but some products are designed to be less toxic to fish and amphibians than others. 
  • Environmental monitoring: It’s vital to monitor waterways for herbicide residue after application. This may include testing for adverse effects on aquatic organisms to ensure populations remain healthy. 

• Application best practices: To enhance safety, always apply herbicides during low flow periods, and use techniques to minimise drift and protect non-target species. 

Shop the best herbicides for controlling aquatic weeds now. Get in touch with the Specialist Sales team for product recommendations to suit your needs.