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SID 5 Research Project Final Report

SID 5 (Rev. 3/06) Page 1 of 9

NoteIn line with the Freedom of Information Act 2000, Defra aims to place the results of its completed research projects in the public domain wherever possible. The SID 5 (Research Project Final Report) is designed to capture the information on the results and outputs of Defra-funded research in a format that is easily publishable through the Defra website. A SID 5 must be completed for all projects.

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ACCESS TO INFORMATIONThe information collected on this form will be stored electronically and may be sent to any part of Defra, or to individual researchers or organisations outside Defra for the purposes of reviewing the project. Defra may also disclose the information to any outside organisation acting as an agent authorised by Defra to process final research reports on its behalf. Defra intends to publish this form on its website, unless there are strong reasons not to, which fully comply with exemptions under the Environmental Information Regulations or the Freedom of Information Act 2000.Defra may be required to release information, including personal data and commercial information, on request under the Environmental Information Regulations or the Freedom of Information Act 2000. However, Defra will not permit any unwarranted breach of confidentiality or act in contravention of its obligations under the Data Protection Act 1998. Defra or its appointed agents may use the name, address or other details on your form to contact you in connection with occasional customer research aimed at improving the processes through which Defra works with its contractors.

Project identification

1. Defra Project code PH0422

2. Project title

Development of eradication strategies for Ludwigia species

3. Contractororganisation(s)

Centre for Ecology and HydrologyCEH WallingfordMaclean BuildingCrowmarsh GiffordWallingfordOxon, OX10 8BB

54. Total Defra project costs £ 9,650(agreed fixed price)

5. Project: start date................ 22 August 2006

end date................. 31 March 2007


6. It is Defra’s intention to publish this form. Please confirm your agreement to do so...................................................................................YES NO (a) When preparing SID 5s contractors should bear in mind that Defra intends that they be made public. They

should be written in a clear and concise manner and represent a full account of the research project which someone not closely associated with the project can follow.Defra recognises that in a small minority of cases there may be information, such as intellectual property or commercially confidential data, used in or generated by the research project, which should not be disclosed. In these cases, such information should be detailed in a separate annex (not to be published) so that the SID 5 can be placed in the public domain. Where it is impossible to complete the Final Report without including references to any sensitive or confidential data, the information should be included and section (b) completed. NB: only in exceptional circumstances will Defra expect contractors to give a "No" answer.In all cases, reasons for withholding information must be fully in line with exemptions under the Environmental Information Regulations or the Freedom of Information Act 2000.

(b) If you have answered NO, please explain why the Final report should not be released into public domain

Executive Summary7. The executive summary must not exceed 2 sides in total of A4 and should be understandable to the

intelligent non-scientist. It should cover the main objectives, methods and findings of the research, together with any other significant events and options for new work.

The objective of this project was to establish the extent of Ludwigia in the UK and determine an appropriate method for the eradication of the species before it becomes widespread.

Several reports of Ludwigia have been received, but as the species is not perceived as a threat by the general public, less interest has been shown in the species than would have been desirable.

We have produced a distribution map for the current known locations. This will be updated and possibly put on a dedicated website for the control of Ludwigia.

We have shown that the herbicide glyphosate achieves approximately 75% reduction in biomass in one year, which is not sufficient to control or eradicate the species in the long term, even with two treatments. The addition of 2,4-D amine at 10% of the recommended label rate did not increase the long term percentage control of the species.

Control of approximately 75% was achieved using glyphosate and glyphosate + 2,4-D amine mixtures. However control of 97.81% was achieved using the glyphosate and non-oil soya sticking agent (code name TFWLM1) . We assume that this is due to prolonged slow release of the herbicide into the plant, increasing the opportunity for continued inhibition of appropriate enzyme system targeted by glyphosate.

We had assumed that the addition of 2,4-D amine to the mixture at sub-lethal levels would encourage the uptake of glyphosate into the plant. While this technique has been shown to be effective on Japanese Knotweed (TCM personal communication) it does not appear to have any effect on this species.

The non-oil soya sticking agent is not yet registered for use in Europe, but has shown considerable potential in trials and field use in the USA. We intend to encourage the company to register the product in Europe for the start of the 2008 spraying season.

We were able to achieve near eradication of Ludwigia peploides within one growing season, preventing flowering and seed set using glyphosate and a soya sticking agent.


Project Report to Defra8. As a guide this report should be no longer than 20 sides of A4. This report is to provide Defra with

details of the outputs of the research project for internal purposes; to meet the terms of the contract; and to allow Defra to publish details of the outputs to meet Environmental Information Regulation or Freedom of Information obligations. This short report to Defra does not preclude contractors from also seeking to publish a full, formal scientific report/paper in an appropriate scientific or other journal/publication. Indeed, Defra actively encourages such publications as part of the contract terms. The report to Defra should include: the scientific objectives as set out in the contract; the extent to which the objectives set out in the contract have been met; details of methods used and the results obtained, including statistical analysis (if appropriate); a discussion of the results and their reliability; the main implications of the findings; possible future work; and any action resulting from the research (e.g. IP, Knowledge Transfer).

The species in Britain

There are reports of two species of Ludwigia occurring in Britain, Ludwigia peploides and Ludwigia uruguayensis. The latter is also known as L. grandiflora because of its very large flowers (c 5cm in diameter). It is also differentiated from L. peploides by possession of hirsute leaves and stems. To date I have not found or been sent any samples resembling L. uruguayensis and I conclude that the horticultural misnomer has been used for specimens of L. peploides. This does not exclude the possibility of L. uruguayensis occurring in natural locations in the UK.

For this reason I have concentrated on the biology, ecology and control of L. peploides in this report.

Scientific Name: Ludwigia peploides (Kunth) Raven

Synonyms: Jussiaea californica (L.) Jeps., Jussiaea patibilcensis Kunth, Jussiaea peploides Kunth, Jussiaea polygonoides Kunth, Jussiaea repens L. vars. peploides (Kunth) Griseb., Jussiaea californica Wats. Common Name: floating primrose-willow, creeping water-primrose

Other synonyms: the species of often sold as Jussiaea grandiflora, the synonym of L. uruguayensis, although I do not believe that this is the correct nomenclature. I believe it is a name adopted by the horticultural trade because it sounds better – grandiflora implying showy flowers etc..

Description and Variation

Ludwigia peploides is a herbaceous, perennial, wetland obligate plant, which can be categorized as a creeping macrophyte (Rejmánková, 1992), meaning that is it an emergent macrophyte with stems that grow prostrate to the mud or float on the water’s surface. Stems are fleshy and reach a length between 20-300 cm long and are typically glabrous (smooth and hairless) or villosulous (slightly pubescent) with long, soft hairs. Leaves are alternately arranged are variable in shape and size. They can be lanceolate (longer than wide and usually tapering at both ends), oblanceolate (broader above the middle of the leaf, then tapering at base), or obovate (egg-shaped, wider at leaf tip), although leaves are typically round during the early growth period. Petiole length ranges between 2.5-3.7 cm, and the leaf blade ranges in length between 1-9 cm. The leaf veins are light green and pinnately arranged.

L. peploides forms two kinds of roots: those for substrate anchorage and nutrient absorption; and adventitious roots, which occur at the stem internodes and can absorb atmospheric oxygen. They are also important for the survival of plant fragments. Flowers are long-stalked, occur in the axils, and have five bright yellow petals (1.0-1.5 cm in length) and typically ten stamens surrounding a cylindrical, short-styled ovary containing numerous ovules. The calyx is bright green, and sepals are between 3-12mm. The fruit capsule is hard, cylindrical, 4-5 chambered, and often droop on a long (ca. 9 cm) stalk. Seeds (including endocarp) are 1 mm and uniseriate (arranged in single row) in each locule (chamber).


Ludwigia peploides is morphologically similar to other noxious water-primrose L. hexapetala and L. uruguayensis. They can only be differentiated when flowering: L. peploides flowering stems typically grow prostrate and the petals are usually 1-1.5 cm and the anthers are 1-1.7 mm whereas L. uruguayensis flowering stems grow erect and its petals are larger, 1.5-2.5 cm, and the anthers are 2.5-3.5 mm. Additionally, the two bractlets (small, specialized leaves at the base of the flower) of L. peploides are deltate (triangular) or ovate (egg-shaped), whereas the bractlets of L. hexapetala are ovate to obovate.

There are three subspecies of L. peploides: glabrescens; montevidensis; and peploides. While both subspecies montevidensis and peploides occur in California, only peploides is native. The subspecies montevidensis is native to southern South America (Ditomaso and Healy, 2003). These two subspecies can be differentiated by foliage surface, leaf apex (leaf tip when it attached to stem) and fruit capsule size. According to Ditmaso and Healy (2003), in peploides, the leaves are glabrous (smooth and hairless), the leaf apex is not glandular, and the fruit capsules are 10-25 mm. In montevidensis, the leaves are pubescent with glandular hairs, the leaf apex is glandular, and the fruit capsules are 25-40 mm.

Economic Importance

The floating mats reduce water flow, increase sedimentation, lower pH and dissolved oxygen, and can harbour disease-carrying mosquitoes. It can easily spread between waterways, and once established, L. peploides is very difficult to control. The European and Mediterranean Plant Protection Organization added to their EPPO Alert List in 2004. The New Zealand Plant Conservation Network lists it as an Unwanted Plant Organism.

Detrimental

The dense, sprawling mats, which can weigh 2 kg/m2 (dry weight) (Cemagref, 2004) clog waterways, can impede navigability, hunting, fishing, irrigation, and water drainage (EPPO, 2004). The reduction of water flow increases sedimentation, which further reduces water flow (Cemagref, 2004). The mats also displace native wetland plants (Grillas, 1992 as cited in Azner et al., 2003), including native Myriophyllum in France, which provides habitat for many macroinvertebrates upon which some fish feed (Cemagref, 2004). The mats also reduce pH and dissolved oxygen in the water (Cemagref, 2004), making the habitat less hospitable for many aquatic organisms. By outcompeting wetland grasses, L. peploides can reduce grazing space for livestock when it displaces wetland grasses (Cemagref, 2004), since the plant is unpalatable due to concentrations of saponins and calcium oxalate (EPPO, 2004). As with L. hexapetala, it could easily be dispersed by shipping, waterfowl, and human activity; moreover, this plant can be spread geographically through the aquarium and horticultural trade (EPPO, 2004). Once established, canal systems facilitate its spread into connected marshes (Aznar et al., 2003). The fast growth rate of L. peploides allows it to dominate areas quickly. For example, it only took five years for a small population of Ludwigia (few dozen square meters) to cover 321 acres (1.30 Km2) in France (EPPO, 2004). Floating mats of this plant can indirectly increase mosquito populations by making the larvae inaccessible to mosquito-eating fish (Pillsbury, 2005).

Beneficial

Ludwigia peploides has potential for wastewater treatment, especially in areas where it is considered native, because its nitrogen-absorbing capabilities exceed those of water hyacinth, Eichhornia crassipes (Rejamánková, 1992).

Habitat

L. peploides is a perennial aquatic herb that can grow horizontally on water or mud and can emerge over the water surface. The plant can tolerate water depths up to three meters and grows up to 80 cm above the water surface (EPPO, 2004). It grows in dense mats along shorelines and out into the water. While it typically inhabits the margins of lakes, ponds, ditches and streams, L. peploides can also tolerate dry spells (Rejmankova, 1992). Its negative geomorphic (growing upward instead of towards the ground) roots are capable of absorbing atmospheric oxygen, allowing the plant to tolerate environmentally stressful condition. Moreover, L. peploides can grow under a range of nitrogen levels. However, when L. peploides is introduced to favourable, nutrient-rich conditions, it quickly becomes a dominant competitor (Rejmánková, 1992). It thrives where sites are disturbed (e.g., dredging and water level fluctuations), because these disturbances stress emergent vegetation that would otherwise dominate over L. peploides (Rejmánková, 1992).


Geographic Distribution

L. peploides and L. uruguayensis originate from South America (Argentina and Chile), and they can now be found in North America, Africa, Australia and Europe. Data on their geographical distribution is lacking and complicated by the fact that the genus Ludwigia is under revision.

It is non native and invasive in the following countries:

Belgium Italy, France Netherlands Spain Switzerland United Kingdom Portugal.North AmericaAustraliaCuba

The current distribution of known records is shown in the following Figure. This is up to date as of 26 th October 2007. There are unconfirmed reports of this species in Wales, but we have been unable to substantiate this report.


Growth and Development

Biomass doubling time under outdoor experimental conditions in California is 23 days (Rejmánková, 1992) and has been estimated at 15-20 days under stagnant, natural conditions and 70 days under flowing water conditions in France (Cemagref, 2004). The mean biomass (dry weight) under controlled conditions averaged 652 g m -2 and has been recorded at 2 Kg m-2 dry weight in the field in France (Cemagref, 2004). However, field samples collected from California in Rejmánková’s study (1992) only ranged between 500-700 g m -2 dry weight. Growth appears to be limited by physical space, as opposed to intraspecific competition resulting from overcrowding (Rejmánková, 1992). The crop growth rate of L. peploides has been measured at 4 to 50 g m-2 d-1, exceeding that of the noxious weed waterhyacinth, Eichhornia crassipes (Rejmánková, 1992).

Reproduction

L. peploides spreads primarily through plant fragmentation. Under controlled conditions, a single L. peploides plant was able to regenerate to 67% of its initial biomass in just 45 days after 95% of the stem was removed (Rejmánková, 1992). This study also determined that severance of a stem’s apical tip results in the development of two or three lateral branches. It is not known to what extent seeds play in spread of this plant, though seeds have geminated in laboratory conditions (Cemagref, 2004).

Control Methods

In order to achieve eradication, 100% control must be achieved in the first year. Follow up treatments will usually involved control of seedlings if appropriate, or regrowth from fragments unaffected by herbicides in the first year.

Herbicides

Ludwigia peploides may tolerate low concentrations of residual herbicides (Rejmankova, 1992). Ludwigia has been used to absorb herbicide residues in runoff water (Bouldin et al. 2006). Suarez et al. (2004) report greater than 80% control of Ludwigia species in rice crops using the herbicide halosulfuron-methyl. A 75% reduction in the extent of a Ludwigia infestation in the Laguna de Santa Rosa was been achieved using glyphosate (Pillsbury 2005) and additional herbicides (triclopyr) were used in 2006 to attempt to increase the efficacy (Rose, 2006).

Shading

Shading may have potential for small infestations of Ludwigia species; however, large-scale shading operations may negatively impact other plants, fish, and wildlife (Sears and Verdone, 2005).

Mechanical Methods The U.S. Army Corps of Engineers (2002) recommends mechanical harvesting, hand-cutting, and rotovation. However, caution must be made to remove all plant fragments and roots, otherwise reinfestation can occur. Furthermore, decomposition of crushed or damaged plant material may result in increased nutrient availability and a reduction in dissolved oxygen (Sears and Verdone, 2005)

Biological Control

Cordo and DeLoach (1982) found that the flea beetle, Lysathia flavipes, caused heavy damage and sometimes mortality to L. peploides plants in its native Argentina. The adult and larvae feed on, and eggs are laid on, the leaves of both L. peploides and parrot’s feather, Myriophyllum aquaticum. Based upon field observations and preference studies using L. peploides, M. aquaticum, and 30 other aquatic plants, Cordo and DeLoach (1982) suggested that L. flavipes had good potential as a biocontrol agent in the United States and elsewhere and recommended other studies, e.g., host range, be conducted.

McGregor et al. (1996) report the activity of another Lysathia species feeding on L. grandiflora. Gassmann et al. also report on the potential of Lysathia flavipes for the control of Ludwigia peploides. Oberholzer et al. (2007) however sound a note of caution on the use of Lysathia species, saying that they are usually not efficient enough


feeders to provide long term control of the other host species Myriophyllum aquaticum and have started work on Listronotus marginicollis weevil. Listronotus elongatus is known to be a potent biocontrol agent of Hydrocotyle ranunculoides another nuisance aquatic weed species in Europe.

Attempt to eradicate

Methods:

We used one population in Cadnam in the New Forest for all the following treatments. Data are mean of three replicate samples taken using a 25 cm2 quadrat randomly place din the plot. All material (roots and shoots) was washed and dried to constant weight in a drying oven at 60C for 72 hours before being weighed for dry weight. We used an approved aquatic formulation of glyphosate containing 360 g/L active ingredient (Roundup Pro Biactive) applied at 6 l product per hectare, equivalent to 2.16 Kg a.i per hectare in all cases. Glyphosate and Glyphosate + 2,4-D amine were applied in 2006, and glyphosate and non-oil soya were applied in 2007. 2,4-D amine and the non-oil soya adjuvant (code name TFWLM1) were both applied at 450 ml/hectare as tank mixtures.

Table: Dry weight of Ludwigia peploides at Cadnam after treatment with various herbicide mixtures.

Treatment Dry weight at Time 0(kg m-2)

Dry weight at + 21 Days(kg m-2)

Dry weight at + 56 days(kg m-2)

Glyphosate 2.10 ± 0.22 1.15 ± 0.32 0.45 ± 0.07Glyphosate + 2,4-D Amine 2.05 ± 0.08 0.86 ± 0.11 0.63 ± 0.09Glyphosate + non-oil Soya 2.21 ± 0.13 0.63 ± 0.28 0.06 ± 0.03Control – no treatment 2.06 ± 0.19 2.35 ± 0.27 2.15 ± 0.33

Results

Control of approximately 75% was achieved using glyphosate and glyphosate + 2,4-D amine mixtures. However control of 97.81% was achieved using the glyphosate and non-oil soya sticking agent. We assume that this is due to prolonged slow release of the herbicide into the plant, increasing the opportunity for continued inhibition of appropriate enzyme system targeted by glyphosate.

We had assumed that the addition of 2,4-D amine to the mixture at sub-lethal levels would encourage the uptake of glyphosate into the plant. While this technique has been shown to be effective on Japanese Knotweed (TCM personal communication) it does not appear to have any effect on this species.

The non-oil soya sticking agent is not yet registered for use in Europe, but has shown considerable potential in trials and field use in the USA. We intend to encourage the company to register the product in Europe for the start of the 2008 spraying season.

References to published material9. This section should be used to record links (hypertext links where possible) or references to other

published material generated by, or relating to this project.

Aznar, J-C, Dervieux, A. and P. Grillas. 2003. Association between aquatic vegetation and landscape indicators of human pressure. Wetlands 23(1): 149-160.

Bouldin J.L., Farris, JL., Moore, MT, Smith, S. and C.M. Cooper (2006) Hydroponic uptake of atrazine and lambda-cyhalothrin in Juncus effusus and Ludwigia peploides Chemosphere, 6: 1049- 1057

Cordo, H.A. and C.J. DeLoach. 1982. The flea beetle, Lysathia flavipes, that attacks Ludwigia (water primrose) and Myriophyllum (parrot feather) in Argentina. The Coleopterists Bulletin 36(2): 298-301.

Ditomaso, J. M. and E.A. Healy. 2003. Aquatic and Riparian Weeds of the West. Oakland, California:


University of California Agriculture and Natural Resources. Dutartre, A. (2004). The invasion of the Ludwigia peploides. Cemagref Research Examples. June 2004.

Cemagref. 12 Sep. 2005.

EPPO (2004) Ludwigia peploides and L. uruguayensis (=L. grandiflora). EPPO Alert List. 6 October 2004. European and Mediterranean Plant Protection. 12 Sep. 2005.

Fisher, B. 1998. Grower’s Weed Identification Handbook. Oakland (CA): University of California – Division of Agriculture and Natural Resources. Publication # 4030. p. WI-215.

Gassmann A, Cock M, Shaw R, Evans H (2006) The potential for biological control of invasive alien aquatic weeds in Europe: a review. Hydrobiologia 570: 217-222

Gleason, H.A. and A. Cronquist. 1991. Manual of Vascular Plants of North-eastern United States and Canada, Second Edition. New York: The New York Botanical Garden. Pp 313-315.

Grillas, P. 1992. Les communautés de macrophytes submerges des marais temporaires oligohalims de Camargue. Etude expérimnetale des causes de la distribution des espéces. Ph.D. Dissertation. University of Rennes I. Rennes, France.

Haragan, P.D. 1991. Weeds of Kentucky and Adjacent States: A field guide. USA: University Press of Kentucky. Pp. 126-127.

McAvoy, W.A. Non native plants of Delaware. June 2001. Delaware Natural Heritage Program. 1 Oct.

2005. McGregor, MA, Bayne, DR, Steeger, JG, Webber, EC and Reutebuch, E, (1996) The Potential for

Biological Control of Water Primrose (Ludwigia grandiflora) by the Water Primrose Flea Beetle (Lysathia ludoviciana) in the South-eastern United States. Journal of Aquatic Plant Management, 34: 74-76.

Natural Resources Conservation Service. PLANTS Database. U.S. Department of Agriculture. 12 Sep. 2005

.Oberholzer, IG Mafokoane, DL & Hill, MP (2007) The Biology and Laboratory Host Range of the Weevil

Listronotus marginicollis (Hustache) (Coleoptera: Curculionidae), a Natural Enemy of the Invasive Aquatic Weed Myriophyllum aquaticum (Velloso) Verde (Haloragaceae) (Parrot’s Feather). Water Research Commission Report No: KV 180/07 ISBN: 978-1-77005-528-5.

Pillsbury, D. (2005) Outbreak of mosquitoes raises possible threat of West Nile Virus. Sonoma West Times & News. 20 Jan. 2003. Archives. 10 October

Radford, A.E., Ahles, H. E., and R.C. Bell. 1968. Manual of the Vascular Flora of the Carolinas. North Carolina: The University of North Carolina Press. Pp. 744-745.

Rejmankova, E. 1992. Ecology of creeping macrophytes with special reference to Ludwigia peploides (H.B.K.) Raven. Aquatic Botany 43: 283-299.

Rose, B (2006) Ludwigia war not won yet. Press Democrat, April 20, 2006 http://www.lagunadesantarosa.org/pdfs/4-20-06%20Press%20Democrat.pdf

Sears, A.L.W. and L.N. Verdone. 2005. Ludwigia hexapetala management plan for the Laguna de Santa Rosa, Sonoma County, California. California: The Sonoma County Ludwigia Task Force. # 2005-2010. 23 p.

Suárez, L., Anzalone, A., Moreno, O. (2004) Evaluation of halosulfuron-methyl herbicide for weed control in rice (Oryza sativa L.) Bioagro, 2004, 16: 173-182

U.S. Army Engineers Research and Development Center. Aquatic Plant Information System. 16 Aug.

2002. U.S. Army Corps of Engineers. 14 Sep. 2005

U.S. Army Engineers Research and Development Center. Noxious and Nuisance Plant Information System. 16 Aug. 2002. U.S. Army Corps of Engineers. 14 Sep 2005.


http://www.lagunadesantarosa.org/pdfs/4-20-06%20Press%20Democrat.pdf

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General enquiries on this form should be made to: - GOV.UKrandd.defra.gov.uk/Document.aspx?Document=PH0422_7090_FRP.doc · Web viewThis form is in Word format and the boxes may