New Zealand seeking herbicides approval for aquatic weeds control

The New Zealand Environmental Protection Authority (EPA) is seeking submissions on an application to allow a number of herbicides to be used over water to control aquatic pest plants.

The application is being made by the Agricultural Reassessment Group (ARG), on behalf of 12 regional councils, as well as the Department of Conservation, Ministry for Primary Industries, Land Information New Zealand and Mighty River Power.

The group is seeking approval to use herbicides containing one of four active ingredients (haloxyfop-R-methyl, imazapyr isopropylamine, metsulfuron-methyl or triclopyr triethylamine).

These substances are currently approved for use on land in New Zealand. They target a range of pest plant types, including Manchurian wild rice, Spartina, alligator weed, yellow flag iris and some grasses and sedges. Many of these pest plants also inhabit aquatic environments such as coastal harbours, the riparian margin or form floating mats.

In its application, the ARG states that the use of these substances over water will complement existing pest plant control methods and help fulfil the group’s statutory obligations under the Biosecurity Act to control and eradicate, where possible, invasive pest plant species.

The ARG has identified a limited number of potential risks to organisms within the aquatic environment related to the uncontrolled use of the substances onto or into water.  It considers that these risks will be reduced through a range of existing and proposed controls on the use of the substances.

The EPA is now seeking submissions from the public on the application. Submissions will close on 11 September, 2012.