Species	Distribution
Water primrose (Ludwigia grandiflora) Photo courtesy of GB Non Native Species Secretariat	To view NBN location data click here
Impacts	Pathways
Forms dense rafts and outcompetes native plant species. Reduced light levels below the rafts can cause die off of waterweeds and algae and reduce water oxygenation levels killing fish and other fauna. Has been linked to significant losses of biodiversity in France. Has cost France millions of Euros where it has become established. Blocks water bodies and drainage systems and may lead to an increased risk of flooding. Impedes bathing and boating	Popular pond and aquarium plant and as such may arrive by trade and/or inappropriate disposal of the plant. Disperses through plant fragments
Management
Prevention Should not be released in the wild. Dispose of garden and pond waste responsibily. Check vehicles, boats, equipment and clothing for plant fragments when leaving infested sites and clean if necessary. Physical Control Mechanical removal is not recommended as the plant spreads through fragmentation. Chemical Control A recently completed Defra funded research project has shown that treatment with glyphosate herbicide reduces biomass by 75% in one year. This is not sufficient to eradicate the species even with two treatments. However a 97.8% reduction in biomass was ahieved using glyphosate and a non-oil soya sticking agent (codename TFWLM1). This latter product is not yet licensed for use in Britain but may be registered in the near future. To download final report of research project click here.   Biological Control Unknown
Links
Non Native Species Secretariat identification guide (Not yet available) Non Native Species Secretariat Fact Sheet SNH SAF Training Manual Invasive Species Ireland Fact Sheet Daisie Species Fact Sheets