MAF acts to control two pest plants found in West Auckland wetland

23 December 2011

The Ministry of Agriculture and Forestry is taking immediate action to eradicate two aggressive aquatic pest plants found in a West Auckland wetland this week.

Salvinia and water hyacinth were found in Lake Te Henga, a privately-owned inland wetland in West Auckland, by local biosecurity officers during regular monitoring of the area.

MAF will spray the affected area of the lake today to prevent the plants from spreading.

“Salvinia and water hyacinth are very aggressive aquatic weeds and grow very quickly in warmer areas in the North Island,” says Victoria Lamb, Senior Adviser Plant Response. “Although they are pretty plants, both destroy habitats for our native aquatic plants and animals. They also block drains and irrigation systems and stop people from enjoying water-based recreational activities.

“They are some of the worst aquatic weeds elsewhere in the world.”

A small area of the lake and lakeshore will be contained to prevent the weeds spreading any further. This area will inaccessible for about a month until biosecurity officers are sure both pest plants have been completely eradicated from the lake.

The plant pests have grown about 5m x 10m, which indicates that they only recently been introduced to the lake.

People with any information about on how the weeds were introduced to the lake or any sightings of salvinia and water hyacinth can report it to MAF’s Pest Hotline – 0800 80 99 66. Fact sheets of pest plants are available on MAF’s website: www.biosecurity.govt.nz .

Photos of both plants are available to media. For more information, contact MAF Communications: 029 894 0328.

Background information

What is salvinia?

Salvinia is a freshwater plant that forms dense mats on the water surface. It can double its size in two days and causes problems for native plants and animals, recreational activities, and drainage and irrigation systems. It is banned from sale, propagation and distribution in New Zealand. Fact sheet: http://www.biosecurity.govt.nz/pests/salvinia

What is water hyacinth?

Water hyacinth forms dense floating mats with pretty flowers from mid-summer to early autumn. It causes problems for native aquatic plants and animals and is banned in New Zealand. Fact sheet: http://www.biosecurity.govt.nz/pests/water-hyacinth