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Caesalpinia decapetala (tree, shrub)  |
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Management Information
Preventative measures: A Risk Assessment of
Caesalpinia decapetala for Hawai‘i 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 plant 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 20 and a recommendation of: "Likely to cause significant ecological or economic harm in Hawai‘i and on other Pacific Islands as determined by a high WRA score, which is based on published sources describing species biology and behaviour in Hawai‘i and/or other parts of the world."Chemical: Mysore thorn is sensitive to foliar applications of glyphosate and triclopyr, and to soil applications of tebuthiuron. Adequate coverage of Mysore thorn foliage in dense infestations is difficult. Timely repeat applications (3-9 months) of triclopyr ester at 113.4grms/acre (0.25 lb/acre) allows gradual reductions and opening of the canopy and eventual control. This strategy not only stresses the Mysore thorn over a longer period but also controls newly germinated Mysore thorn seedlings. Accessible stems may be treated basal bark with triclopyr ester at 20% product in diesel or crop oil in very low volume applications (PIER, 2002).
Location Specific Management InformationAustralia
Mysore thorn is listed as an environmental weed of subtropical rainforest and remnants in New South Wales. East Maui (United States (USA))
With sharp thorns all the way to the ground, controlling C. decapetala in this steep gulch in Halehaku would be difficult. At this location, C. decapetala may not be a feasible target for eradication, but through delineation of the area and education, it may be possible to keep it from invading throughout the watershed. Raoul Is. (New Zealand)
A concerted effort has been made to control Mysore thorn on Raoul Island, and it is now uncommon, although it is not possible to inspect disturbed cliff sites (Timmins and Braithwaite, 2002). This species is subject to an eradication programme on Raoul Island, and is ranked Category A(i) - known to have the potential to significantly alter the vegetation of Raoul Island. Eradication commenced in 1974. Raoul Island has been divided into 13 weeding blocks for the purpose of controlling and eradicating alien plants since 1972, which make up 64% of the vascular plant flora on Raoul Island. These are divided into active plots which are searched at least twice a year, and null plots which are searched at least once every two years. Grid searching is used to examine the areas with easier access, while steep cliffs are searched using binoculars or a telescope. This is carried out when plants such as C. decapetala are in flower (June-November). Aerial surveillance is carried out periodically which has been useful in identifying flowering trees such as Senna septemtrionalis, mature vines of Passiflora edulis or trees of Olea europaea ssp. cuspidata. The initial knockdown phase involved for most species the cutting of mature individuals and painting of stumps with herbicides, or scattering herbicide granules around them. Blanket spraying was used to treat dense, inaccessible infestations. Subsequent searches involve the removal of any seedlings or young plants found. If a mature plant is found, the fruit is removed for burning, the stem is cut and herbicide applied. Information regarding the eradication programme is stored on an Access database. Helicopter application of herbicide was used in the case of C. decapetala. Areas of C. decapetala vines were burned and cleared, to hasten the decline of seeds in the seedbank. This species once occupied 22 ha of Denham Bay, but since 2000 only 600-700 plants have been removed, the majority of which were seedlings. Between 1997 and 2000, 44,877 individual plants were removed. The importation of alien plants to Raoul Island is prohibited. South Africa
A combination of mechanical and chemical options are recommended. Seedlings can be uprooted. When larger plants are slashed care should be taken to remove the entire root system as Mysore thorn coppices easily. It is also recommended to apply a herbicide after cutting (Stalk Immersion: try Garlon® 4 50ml/10l water; Foliar spray: use Garlon® 4 50ml, Roundup®, etc 300ml or Muster® 150ml/10l water).
Indigenous alternatives suggested are coast climbing thorn Acacia kraussiana ; spiny splinter bean Adenopodia spicata and grey nickernut creeper Caesalpinia bonduc.
Management Resources/Links
1. Alien Invader Plants, 2004
Summary: Notes on Mysore thorn in South Africa, includes information on common names, management, dispersal and alternative species to use.
Available from: http://www.geocities.com/wessaaliens/species/mthorn.htm [Accessed 17 June 2003]. 2. Daehler, C.C; Denslow, J.S; Ansari, S and Huang-Chi, K., 2004. A Risk-Assessment System for Screening Out Invasive Pest Plants from Hawaii and Other Pacific Islands. Conservation Biology Volume 18 Issue 2 Page 360.
Summary: A study on the use of a screening system to assess proposed plant introductions to Hawaii or other Pacific Islands and to identify high-risk species used in horticulture and forestry which would greatly reduce future pest-plant problems and allow entry of most nonpests. 4. 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] 5. New Zealand Plant Conservation Network, 2005. Unwanted Organisms. Factsheet Caesalpinia decapetala
Summary: The New Zealand Plant Conservation Network (NZPCN) provides information about New Zealand's most weedy exotic plant species and how to identify them. They also provide an on-line form to record observations of weed occurrences.
This page available from: http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/index02.asp?Filter=c&FilterStatus=1
Lists of Exotic Plant life and Weeds available from: http://www.nzpcn.org.nz/exotic_plant_life_and_weeds/advanced_search.asp [Accessed 19 May 2005] Results Page: 1
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