punicea (Brazilian rattlebox) Management Information

Prepared by the IUCN SSC Invasive Species Specialist Group

Contents 1.0 Introduction...... Page 1 2.0 Preventative Measures...... Page 1 3.0 Physical Control...... Page 2 4.0 Chemical Control...... Page 2 5.0 Physical / Chemical Follow Up Techniques ...... Page 3 6.0 Biological Control...... Page 3 7.0 References...... Page 4 8.0 Appendix...... Page 6

1.0 Introduction Commonly known as Brazilian rattlebox, Sesbania punicea is a deciduous, leguminous shrub that grows up to 4m tall (Hoffmann & Moran, 1998). It has been widely distributed from its native range in South America as an attractive ornamental species (Hoffmann & Moran, 1991a; Csurhes & Edwards, 1998). Escapes from cultivation have led to naturalisation in some areas as in southern United States and South Africa; where it has formed dense thickets in riparian and wetland areas excluding native species and altering water flows (Hunter & Platenkamp, 2003). S. punicea is a rapid growing species which produces large amounts of seed capable of long ranged dispersal via water currents (Hunter & Platenkamp, 2003), however, other aspects of its biology may make it vulnerable to some forms of control. These include the reliance on sexual reproduction, being incapable of reproducing vegetatively and a limited seed bank with seeds which do not persist longer than 2-3 years (Hoffmann & Moran, 1998).

2.0 Preventative Measures A Risk Assessment of S. punicea for Hawaii and other Pacific islands was prepared by Dr. Curtis Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service. The alien screening system is derived from Pheloung et al., (1999) with minor modifications for use in Pacific islands (Daehler et al., 2004). The result is a score of 9.5 and a recommendation of: "Likely to cause significant ecological or economic harm in Hawaii and on other Pacific Islands” as determined by a high WRA score, which is based on published sources describing species biology and behaviour in Hawaii and/or other parts of the world (PIER, 2005).

Sesbania punicea was declared noxious in Queensland, Australia in 1994 as a category P1 potential weed; all cultivated specimens designated for retail were subsequently recalled and destroyed (Csurhes & Edwards, 1998). At the time of writing, Queensland was the only state in which the sale of S. punicea was prohibited. Csurhes & Edwards (1998) state that it should be declared noxious in every State and Territory in Australia to ensure that it is not traded as a garden plant and that all cultivated specimens should be removed and destroyed, regardless of their location.

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Sesbania punicea is not present in New Zealand but it has been included as a “Research Organism” in the Auckland Regional Pest Management Strategy 2007-2012 (Auckland Regional Council, 2007). While this means it is not legally recognised as a pest species with currently no restrictions on its propagation and growth (Auckland Regional Council, 2008), research into the potential threat and dispersal pathways of S. punicea is planned to be carried out to determine whether it is capable of causing at some time a serious adverse and unintended effect under the New Zealand Biosecurity Act (Auckland Regional Council, 2007).

3.0 Physical Control Physical control techniques for S. punicea include the hand pulling of first-year and using a weed-wrench for larger individuals (Hunter & Platenkamp, 2003). The effectiveness of physical methods is increased as S. punicea does not produce root sprouts when the shoot is damaged (Hunter & Platenkamp, 2003).

The Sacramento Area Flood Control Agency [SAFCA] produced a long term management and maintenance plan for the Dry Creek Watershed in 2007 which describes physical and chemical control options in more detail. The preferred method detailed in this plan is to hand pull small seedlings up to 3 inches in diameter including the roots, and disposing pulled plants in an upland location outside the floodplain (SAFCA, 2007). For the Dry Creek Watershed, this treatment was best applicable for individuals and sparse infestations located over most of the upper watershed (SFACA, 2007). While up to 3 inches in diameter may indicate a large individual, S. punicea is not known to form deep root systems, making pulling relatively easy (Rice, 1998). Alternatively, hand or power tools can be used to first cut down the plant, and then the roots can be dug up later (Buck et al., undated).

For heavier infestations located in the lower watershed areas there is likely to be a more developed seed bank (SAFCA, 2007). As such, the SAFCA management plan (2007) state that seedling flushes are expected to be moderate during the first few years of the maintenance program, recommending use of cut and paint techniques and herbicide use.

4.0 Chemical Control Repeated foliar applications of glyphosate based herbicides have been reported to be effective in killing small individuals (under 3 feet high) (Hunter & Platenkamp, 2003). Additionally Erasmus et al. (1996) concluded that when applied to cut stumps, most herbicides would be effective in controlling S. punicea, experimentally showing effective control achieved using 2 % imazapyr product in water, 10 % glyphosate product in water, 0.5 % triclopyr product in diesel and 1.5 % triclopyr product in water (Erasmus et al., 1996). The South African Working for Water program has also developed a list of herbicides for use against S. punicea and other invasive plant species (Table 1 in appendix), including their concentrations, how they should be used and estimated product volume per treated hectare (Working for Water, 2002).

As S. punicea is most likely to be found growing close to aquatic habitats, it is recommended that only herbicides approved for use near water are used such as Rodeo™, Aquamaster™ (both glyphosate based) or Garlon 3A™ (triclopyr based) or their generic equivalents (SAFCA, 2007; Buck et al., undated). Cutting and painting using Aquamaster™ was noted as effective in cut and paint techniques in the Dry Creek Watershed as well as spraying 5 % Aquamaster™ mixed with a non-toxic indicator dye in

2 order to more easily identify which plants had been sprayed in the past (SAFCA, 2007; Buck et al., undated). The optimum timing for herbicide application was found to be 1 month after the seasonal water level drop in the creeks (SAFCA, 2007).

To prevent adverse effects on the environment, a number of protection measures in addition to using approved herbicides and non-toxic indicator dyes were devised for herbicide application in the Dry Creek Watershed. These include not spraying plants within 25 feet of flowing water during times of greatest use by anadromous fish (October 16 – May 31), using low pressure sprayers with large droplet size applicator nozzles to minimize aerial drift, not using added surfactants with the herbicide used, not using herbicides during wind speeds greater than 10 miles per hour or if rain is likely in the next 24 hours (or otherwise directed by the herbicide label) and not using herbicides if within 50 -100 feet of elderberry shrubs (Sambucus mexicana), the host plant for the federally listed valley elderberry longhorn beetle (Desmocerus californicus dimorphus) (SAFCA, 2007). Herbicides should also be mixed and stored away from streams to prevent contamination and work crews are to be instructed in the proper identification of S. punicea (SAFCA, 2007).

5.0 Physical / Chemical Follow Up Techniques Although the seeds of S. punicea may not persist in seed banks for longer than 2-3 years (Hoffmann & Moran, 1998), seedlings sprouting during seed bank flushes are almost certain to appear following physical and/or chemical control (SAFCA, 2007; Buck et al., undated). As these seedlings are quickly capable of producing more seed, a number of follow up treatments are required (SAFCA, 2007).

SAFCA (2007) recommends that at least two full treatments per year for the first three years are required, timed appropriately based on plant observations to prevent the seedlings from flowering and setting seed. While seedlings are easily handpulled, Buck et al. (undated) found the most effective treatment to include three follow-up herbicide treatments using Aquamaster™, the first in late spring to treat cut-stumps followed by a treatment in mid-summer for the first flush of new seedlings and one in early fall for the second flush of seedlings (Buck et al., undated).

A technique known as “flaming” or “blanching” was tested in the Dry Creek Watershed and consists of passing a flame over emerging seedlings effectively boiling the plants (SAFCA, 2007). Buck et al. (undated) found this technique to be very effective in controlling emerging seedlings, but not re-sprouting stumps, especially those in areas with a high water table. If utilised, SAFCA (2007) recommends usage when the vegetation is completely wet to reduce the chance of wildfires, the most effective window therefore during the wet season, on the very first seedlings to emerge (SAFCA, 2007).

6.0 Biological Control In South Africa, preliminary studies on suitable biological control agents started in 1972, prior to S. punicea being officially declared a pest in 1979 (Hoffmann & Moran, 1991a). The first of these was a florivorous apionid, Trichapion lativentre which was thought to have been introduced through tourists from Argentina in the late 1970’s (Hoffman & Moran, 1988; in Moran & Hoffmann, 1989). Trichapion lativentre initially showed promising results, having devastating direct and indirect effects on the productivity of S. punicea through adults and larvae feeding on flower buds and adults feeding on leaves (Moran & Hoffmann, 1989; Hoffmann & Moran, 1998). While seed production was

3 consistently reduced by an average of 98 % with surveys showing a drastic decline in seedling recruitment rates, there was not a corresponding decline in the density of mature stands (Hoffmann & Moran, 1991b). This was an unexpected result, as S. punicea relies on sexual reproduction, has short lived seeds in the seed-bank, and only lives for 10 – 15 years with relatively rapid turnover rates within populations (Hoffmann & Moran, 1991b). Despite this, the effects of T. lativentre were noted to have slowed the spread of S. punicea into uninvaded habitats and impeded reinvasion into previously cleared areas (Hoffmann & Moran, 1991b).

The seed feeding curculionid Rhyssomatus marginatus was subsequently released in 1984 to supplement the effects of T. lativentre (Hoffmann & Moran, 1992). Rhyssomatus marginatus oviposits into the seeds of S. punicea, its larvae emerging and feeding on the seed it was laid on, as well as an adjacent and sometimes a third seed (Hoffmann & Moran, 1992). Although there were concerns that R. marginatus would be unable to survive after the depletion of seeds by T. lativentre, the two species managed to coexist with R. marginatus playing an important supplementary role in depleting 88% of the remaining seeds regardless of the location of S. punicea populations (Hoffmann & Moran, 1992). Over a period of 10 years however, this high level of seed destruction only resulted in a marginal decline of population density at only one of the study sites (Moran et al., 2003).

The stem-boring curculionid, Neodiplogrammus quadrivittatus whose larvae bore into the stem and trunks of plants causing damage to vascular tissue resulting in branch and mature tree die-back was introduced in 1985 (Hoffmann & Moran, 1998). The combination of all three of these species has been a success with S. punicea being now almost irrelevant as an invasive plant, but would not have been achieved by any of the three acting in isolation (Hoffmann, 1990; Hoffmann & Moran, 1998). Simulation models showed that rates of seed predation by R. marginatus alone were insufficient in reducing the density of populations and while N. quadrivittatus was capable of killing larger individuals and reducing S. punicea density, simulation models demonstrated that seedlings would have likely rapidly re-established in the absence of seed and flower predators (Hoffmann; 1990; Hoffmann & Moran, 1998). Simulation modelling also showed that optimal results were achieved when the stem-boring N. quadrivittatus was introduced 5 years after the other two, so that seed banks would already be depleted and minimal seedling recruitment occurs (Hoffmann, 1990).

Of importance is the fact that while T. lativentre is a more mobile species which was able to spread to all S. punicea invaded sites, the other two species were less mobile and as such, needed to be released at specific sites (Hoffmann & Moran, 1998). Furthermore, biological control agents (T. lativentre in particular) were found to be less effective when the host S. punicea populations were in proximity to citrus orchards (Hoffmann & Moran, 1995). This was believed to have been due to the spraying of these orchards with organophosphate insecticides, the effectiveness of T. lativentre apparently increasing with distance away from the closest sprayed orchard (Hoffmann & Moran, 1995).

7.0 References Auckland Regional Council. (2007). Regional Pest Management Strategy 2007 - 2012. Part V: Research Programme. Retrieved July 21, 2010 from Auckland Regional Council website: http://www.arc.govt.nz/albany/fms/main/Documents/Environment/Plants%20and% 20animals/RPMS/RPMS%20Part%20V%20Research%20Programme.pdf

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Auckland Regional Council. (2008). Plant details: Brazilian rattlebox. Retrieved July 21, 2010 from Auckland Regional Council website: http://www.arc.govt.nz/environment/biosecurity/search-for- plants/index.cfm?63E0F20E-14C2-3D2D-B905- 50098EBBE4B9&plantcode=Sespun Buck, P., May, L., Lucas, S., & Evans, E. (undated) Dry Creek Watershed red sesbania control project. Retrieved July 19, 2010 from The California Invasive Plant Council website: http://www.cal- ipc.org/symposia/archive/pdf/May%20sesbania.pdf Csurhes, S., & Edwards, R. (1998). Potential environmental weeds in Australia: candidate species for preventative control. Environment Australia: National Weeds Program. Erasmus, D.J., Viljoen, B.D., & Coetzer, R.L.J. (1996). Efficacy of selected herbicides applied to Sesbania punicea stumps. Applied Plant Science, 10(1), 12-15. Hoffmann, J.H., & Moran, V.C. (1991a). Biological control of Sesbania punicea () in South Africa. Agriculture, Ecosystems and Environment, 37, 157- 173. Hoffmann, J.H., & Moran, V.C. (1991b). Biocontrol of a perennial legume, Sesbania punicea, using a florivorous weevil, Trichapion lativentre: weed population dynamics with a scarcity of seeds. Oecologia, 88, 574–576. Hoffmann, J.H., & Moran, V.C. (1992). Oviposition patterns and the supplementary role of a seed-feeding weevil, Rhyssomatus marginatus (Coleoptera: Curculionidae), in the biological control of a perennial leguminous weed, Sesbania punicea. Bulletin of Entomological Research, 82(3), 343-347. Hoffmann, J.H., & Moran, V.C. (1995). Localized failure of a weed biological control agent attributed to insecticide drift. Agriculture Ecosystems & Environment, 52(2- 3), 197-203. Hoffmann, J.H., & Moran, V.C. (1998). The population dynamics of an introduced tree, Sesbania punicea, in South Africa, in response to long-term damage caused by different combinations of three species of biological control agents. Oecologia, 114, 343–348. Hunter, J.C., & Platenkamp, G.A.C. (2003). The hunt for red sesbania: biology, spread, and prospects for control. In California Exotic Pest Plant Council (Cal-EPPC) News, Protecting California’s Natural Areas from Wildland Weeds, Vol. 11, No. 2, Summer 2003. Moran, V.C., & Hoffmann, J.H. (1989). The effects of herbivory by a weevil species acting alone and unrestrained by natural enemies on growth and phenology of the weed Sesbania punicea. Journal of Applied Ecology, 26(3), 967-978. Moran, V.C., Hoffmann, J.H., & Olckers, T. (2003). Politics and ecology in the management of alien invasive woody trees: the pivotal role of biological control agents that diminish seed production. In M. Cullen, D.T. Briese, D.J. Kriticos, W.M. Lonsdale, L. Morin & J.K. Scott (Eds.) Proceedings of the XI International Symposium on Biological Control of Weeds Canberra, Australia, 27 April–2 May 2003. [PIER] Pacific Island Ecosystems at Risk (2005). Risk Assessment Sesbania punicea. Retrieved July 19, 2010 from Pacific Island Ecosystems at Risk website: http://www.hear.org/pier/wra/pacific/sesbania_punicea_htmlwra.htm [SAFCA] Sacramento Area Flood Control Agency. (2007). Dry Creek Watershed red sesbania long term management and maintenance plan. May & Associates, Inc. Retrieved July 23, 2010 from Sacramento Area Flood Control Agency website:

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http://www.safca.org/documents/Environmental%20Protections%20page%20folde rs/Protection.SpecialProjects/DryCreekRedSesbaniaLongTermMgmtPlan.pdf Rice, B. (1998). Red alert! Sesbania punicea. Global Invasive Species Team. Retrieved July 22, 2010 from The Nature Conservancy website: http://www.invasive.org/gist/alert/alrtsesb.html Working for Water (2002). Policy for the use of herbicides for the control of alien vegetation. Retrieved July 19, 2010 from South African Department of Water Affairs website: http://www.dwaf.gov.za/wfw/Legal/Docs/doc/Herb%20Policy%2015January%202 002%20.pdf

8.0 Appendix

Target Method Product Rate Comment Estimated Use

Mamba 150 ml / 10 L Glyphosate 4 L / ha Seedlings Foliar Spray water (360g/L) Touch Down (glyphosate 4 L / ha 4 L / ha trimesum 480g/L Do not spray Garlon 4 / trees under Viroaxe 50 ml / 10 L 2 L / ha biological (triclopyr ester 48 water control g/L) Trees Slash and Mamba 150 ml / 10 L Spray when 1m Spray Glyphosate 4 L / ha (360g/L) water tall Coppice Touch Down (glyphosate 4 L / ha 4 L / ha trimesum 480g/L Do not spray Garlon 4 / trees under Viroaxe 50 ml / 10 L Spray when 2m 2 L / ha biological (triclopyr ester water tall control 480g/L) Chopper 200 ml / 10 L (imazapyr 1.5 L / ha water 100g/L) Trees Cut Stump Garlon 4 / Viroaxe 50 ml / 10 L Whole stump 1.5 L / ha (triclopyr ester water 480g/L) Do not apply in 100 ml / 10 L riparian Cut surface only 1.5 L / ha water situations where water Timbrel 3A Cut surface only. (triclopyr amine 300 ml / 10 L Consult Working contamination 2 L / ha can take place salt 360g/L) water for Water technical advisor

Table 1. List of herbicides with their active ingredients, methods and estimated usage effective against Sesbania punicea in South Africa. Adapted from Working for Water (2002).

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