Detailed information sheet

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Botanical name : Salvinia molesta Family : Salviniaceae (salvinia) Common name : salvinia Also known as : water fern, Kariba weed, S. herzogii Where is it originally from? : South America What does it look like? : Free-floating fern (<30cm) with two leaves above the water and one rootlike leaf below. Two leaf types: juvenile leaves well-spaced, small, lying on surface (occasionally only these leaves are produced), while more common rounded mature leaves (1-4x1-5cm)are crowded, compacted, folded about midrib, and the upper surfaces have many rows of water-repellent basket-like hairs. . Are there any similar species? : The juvenile form resembles Azolla species Why is it weedy? : Phenomenal growth rate (can double in 8 days), fragments easily, can survive in damp mud. Tolerates water of any quality, and increased nutrients increase growth rate. Frost-tender, requires high light, high temperature. How does it spread? : Does not produce spores, spreads by fragmentation only through water movement, deliberate ‘liberation’ of aquarium contents into ponds or lakes. What damage does it do? : Covers water surface, blocking light to native species. Rotting vegetation and normal growth consumes oxygen, quickly stagnating water and killing all fauna and flora below. Blanket effect prevents oxygenation by wind. Can harbour other diseases. Which habitats is it likely to invade? : Potential to invade any slow-moving or still freshwater habitat in upper North Island. What can I do to get rid of it? : Biosecurity New Zealand is attempting to eradicate this species from New Zealand. Any suspected new sightings must be reported to your regional council. What can I do to stop it coming back? :

For more detailed botanical descriptions of weed species, check out the Plant Conservation Network's website at http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/index.asp

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*The chemical control methods in this manual were devised by Department of Conservation staff for Department of Conservation operations and should not be used as a substitute for the pesticide manufacturer's label instructions. The Department of Conservation takes no responsibility for any liability or damage to any person, property or thing which may occur as a result of the use of any pesticide in accordance with the chemical control methods contained on this website.

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