Management Information
Preventative measures: QDNRM (2005) suggests that, "Newly established plants should be destroyed before they flower and produce berries. Birds eat the berries, dispersing the seed to new areas. Do not plant green cestrum in gardens, as this acts as a potential point of dispersion. Roadside infestations should be controlled before road grading is carried out. The same recommendation applies in cultivation areas; control the cestrum first. Land which is overgrazed, and therefore has limited plant competition, should be regularly checked for new infestations."A Risk assessment of Cestrum parqui for Australia was prepared by Pacific Island Ecosystems at Risk (PIER) using the Australian risk assessment system (Pheloung, 1995). The result is a score of 11 and a recommendation of: reject the plant for import (Australia) or species likely to be of high risk (Pacific). Mechanical: Croft and Holding (2004) state that, "Mechanical control involves digging up plants by hand and removing all plant material including roots. Due to cestrum's ability to sucker from root fragments, follow up control is often required. Control using an application of mulch to cover and suppress seedling growth has been used. This method retains moisture in the soil and provides protection for native plants sown in conjunction with the mulching operation. It is used following chemical or mechanical control." Chemical: Croft and Holding (2004) state that, "Chemical control involves spot-spray application of herbicides and is used in heavy infestations to knock down mature stands. Alternatively a basal bark application with a dropper bottle can be used on isolated plants. Timing of treatment is important and should be done prior to setting seed. Suckering and seedling growth may occur so follow up treatment will be required." QDNRM (2005) has listed a variety of chemicals used to control C. parqui in a variety of ways. Picloram & triclopyr (Grazon DSR) can be applied late spring to early autumn and to thoroughly cover all leaves and stems. Trichlopyr (Garlon 600R) can be applied if foliage is thoroughly sprayed when C. parqui growth is very active. Amitrole (Amitrole TR) can be used just prior to flowering and applications can be repeated if necessary until sufficient control is achieved. 2,4-D & picloram (Tordon 75-DR) can be used in spot treatment applications. And finally, Picloram & triclopyr-AccessR can be applied as a basal bark or cut stump application (QDNRM, 2005). Biological: QDNRM (2005) states that, "C. parqui seedlings can be suppressed by vigorous competition from other plants. Control adult plants, then plant a vigorous pasture species or local native species, which will compete with seedlings. This method is not always practical on riverbanks and gravel beds. This species can be killed by digging out the plants completely. Care must be taken to remove all the yellow roots, otherwise regrowth will occur. It is preferable to burn the roots."  
Location Specific Management InformationBega Valley
C. parqui is declared noxious in Bega Valley, Eurobodalla and the Shoalhaven, meaning that it must be fully and continuously suppressed and destroyed (Eurobodalla Shire Council, 2004).
Eurobodalla Shire Council (2004) explains that “Seedlings may be hand pulled or dug out. Cut and paint or stem inject mature plants, preferably before they begin to develop seed. To improve the effectiveness when using the cut and paint method, peel the bark back all around the stump and apply herbicide quickly to both the cut face and the exposed outer wood. Spray with selective herbicides. Follow-up treatment will be needed on seedlings”. Eurobodalla
C. parqui is declared noxious in Bega Valley, Eurobodalla and the Shoalhaven, meaning that it must be fully and continuously suppressed and destroyed (Eurobodalla Shire Council, 2004).
Eurobodalla Shire Council (2004) explains that “Seedlings may be hand pulled or dug out. Cut and paint or stem inject mature plants, preferably before they begin to develop seed. To improve the effectiveness when using the cut and paint method, peel the bark back all around the stump and apply herbicide quickly to both the cut face and the exposed outer wood. Spray with selective herbicides. Follow-up treatment will be needed on seedlings”. New South Wales
In Queensland, New South Wales, and Victoria, C. parqui is a declared noxious weed due to its ability to invade agricultural land, and its known toxicity to livestock (Croft and Holding, 2004).
“In the New South Wales communities of Bundeena and Maianbar, Community involvement programs have been highly successful on public land, and on the properties of cooperative landowners who have removed all plants with the help of council. The joint efforts of the community and the council proved to be a great approach, especially for a weed that was found in many home gardens. The nature of the area, however, is a high proportion of ‘weekender’ properties, which are rarely occupied. These present a long-term challenge to the program.
The group is hoping that several highly visible and successful spray events by council, and continued local media releases will improve the likelihood of compliance on private property, which is now where a majority of infestations can be found.
Community support for the program has meant that to date the noxious weeds legislation has not been enacted. It is anticipated, however, that in order to complete the planned eradication of cestrum from the area some landowners will eventually have to be pressured.
Council has now developed a fully integrated management plan for green cestrum. It involves mobilising interested members of the community to participate, liaison with other authorities (especially the NPWS) and using a variety of control methods. As the program progresses it will be measured against outcomes and adapted as required to achieve the stated goals” (Croft and Holding, 2004). New Zealand
C. parqui is included in the First Schedule of the National Pest Plant Accord. All plants on the list are designated as Unwanted Organisms, and are banned from sale, propagation and distribution throughout New
Zealand. Please see National Pest Plant Accord for the complete list. Queensland
In Queensland, New South Wales, and Victoria, C. parqui is a declared noxious weed due to its ability to invade agricultural land, and its known toxicity to livestock (Croft and Holding, 2004). Shoalhaven
C. parqui is declared noxious in Bega Valley, Eurobodalla and the Shoalhaven, meaning that it must be fully and continuously suppressed and destroyed (Eurobodalla Shire Council, 2004).
Eurobodalla Shire Council (2004) explains that “Seedlings may be hand pulled or dug out. Cut and paint or stem inject mature plants, preferably before they begin to develop seed. To improve the effectiveness when using the cut and paint method, peel the bark back all around the stump and apply herbicide quickly to both the cut face and the exposed outer wood. Spray with selective herbicides. Follow-up treatment will be needed on seedlings”. Victoria
In Queensland, New South Wales, and Victoria, C. parqui is a declared noxious weed due to its ability to invade agricultural land, and its known toxicity to livestock (Croft and Holding, 2004).
Management Resources/Links
1. Croft, D., and Di Holding. 2004. A community approach: Green cestrum "factsheet". Cooperative Research Center for Australian Weed Management. 5. National Pest Plant Accord, 2001. Biosecurity New Zealand.
Summary: The National Pest Plant Accord is a cooperative agreement between regional councils and government departments with biosecurity responsibilities. Under the accord, regional councils will undertake surveillance to prevent the commercial sale and/or distribution of an agreed list of pest plants.
Available from: http://www.biosecurity.govt.nz/pests-diseases/plants/accord.htm [Accessed 11 August 2005] 6. QDNRM (Queensland Department of Natural Resources and Mines). 2005. Green cestrum: Cestrum parqui. Document/Fact Sheet PP15. Results Page: 1
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