Chapman and Coffey (1971) reviewed the possible utilization by harvesting for stock food in New Zealand lakes. Though harvesting was considered practicable the use of the plants as fodder was thought to be unsuitable because of the content of arsenic accumulated by the plants from the thermal waters that enter the lakes. Arsenic in amounts of 35–75 ppm dry weight are common, and extreme values up to 2 000 ppm have been recorded. It is possible in other countries that the use of plants as fodder could be practical.
Since the species is dioecious (sexes on different plants) both must be present for sexual reproduction. Only female plants are known outside of the native range of this species. All reproduction in introduced regions is therefore asexual primarily by fragmentation or local growth by rhizomatous spread. (Symoens and Triest 1983).
Principal source: McGregor and Gourlay, 2002 Assessing the prospects for biological control of lagarosiphon (Lagarosiphon major (Hydrocharitaceae))
National Heritage Trust, 2003 Lagarosiphon (Lagarosiphon major)
Compiler: National Biological Information Infrastructure (NBII) & IUCN/SSC Invasive Species Specialist Group (ISSG) with support from the Terrestrial and Freshwater Biodiversity Information System (TFBIS) Programme (Copyright statement)
Review: Robin W. Scribailo Ph.D. Aquatic Botanist Professor of Biological Sciences Director of the Biological Sciences Field Station \ Director of the Aquatic Plant Herbarium Biological Sciences, Purdue University North Central. USA
Publication date: 2006-04-11
Recommended citation: Global Invasive Species Database (2024) Species profile: Lagarosiphon major. Downloaded from http://www.iucngisd.org/gisd/speciesname/Lagarosiphon+major on 08-12-2024.
James et al. (1999) state that, \"L. major creates progressively stressful conditions of high pH and low CO2 content. L. major may be successful in out-competing Elodea spp. as a result of its ability to photosynthesize and consequently grow, particularly under very stressful conditions of high pH and low free CO2, perhaps through more efficient bicarbonate utilization than the other species. There is some indication that the competitive success of L. major may be a consequence of greater toleration to pH stress.
McGregor and Gourlay (2002) state that, \"L. major replaces native vegetation; dense infestations restrict the passage of boats and limit recreational activities like swimming and angling; storms can tear loose the weed and deposit large masses of rotting vegetation on beaches, spoiling their amenity value.
Rattray (1994) states that, \"L. major has successfully out-competed native species wherever it has colonized.\" James et al. (1999) report that, \"L. major has been reported to be actively displacing E. nuttallii and appears to be competitively superior to Elodea spp. in at least some habitats.\"
Chemical: Hofstra and Clayton (2001) report that, \"The aquatic herbicide diquat is the only product registered in New Zealand for controlling the submerged weeds, including lagarosiphon (L. major.\" The authors claim that, \"However, diquat can be ineffective under some environmental conditions and it does not control certain submerged weeds.\" The authors studied three other herbicides (endothall, triclopyr, and dichlobenil), and found that, \"Endothall killed coontail, lagarosiphon and hydrilla and some species of Myriophyllum and Potamogeton but not egeria or species of Chara or Nitella. Only transient growth effects were observed in target plants treated with triclopyr and dichlobenil.\"
Davies et al. (2003) investigated the use of Sulfosulfuron, which is a selective, post-emergence, sulfonylurea herbicide intended for use in winter wheat. The authors found though that, \"Treatment with sulfosulfuron at any concentration stimulated biomass accumulation.\" This product should not be used as a treatment method.
Biological: Lake et al. (2002) state that, \"Selective feeding by rudd may also be significant in lakes that have been invaded by exotic oxygen weeds in New Zealand (e.g. Egeria densa, Elodea canadensis, and Lagarosiphon major) by facilitating their monospecific habit through suppression or exclusion of more desirable species.\"
McGregor and Gourlay (2002) report that, \"The nematode Aphelenchoides fragariae has been recorded attacking the apical tips of L. major causing shoot dwarfing. Nymphula nitens feeds on many aquatic weeds and might be a potential biological control agent, but it also feeds upon native aquatics. Biological control offers the prospect of re-establishing native macrophyte communities in infected waters, however biological control and the removal of L. major may only result in the replacements of one exotic species for another.\"Chapman and Coffey (1971) review the introduction and spread of L. major in New Zealand. The possibility of the use of grass carp was investigated for control so a few fish were imported from Malaysia.Trials showed that carp would eat the problem weeds.