Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service
Information on
Risk Assessments
Original risk assessment
Pacific Island Ecosystems at Risk (PIER)
RISK ASSESSMENT RESULTS: Low risk, score: -8
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Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i. Research directed by C. Daehler (UH Botany) with funding from the Kaulunani Urban Forestry Program and US Forest Service Information on
Risk Assessments |
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Crescentia cujete; common calabash tree |
Answer |
||
|
1.01 |
Is the species highly domesticated? |
y=-3, n=0 |
n |
|
1.02 |
Has the species become naturalized where grown? |
y=-1, n=-1 |
n |
|
1.03 |
Does the species have weedy races? |
y=-1, n=-1 |
n |
|
2.01 |
Species suited to tropical or subtropical climate(s) (0-low; 1-intermediate; 2-high) – If island is primarily wet habitat, then substitute “wet tropical” for “tropical or subtropical” |
See Append 2 |
2 |
|
2.02 |
Quality of climate match data (0-low; 1-intermediate; 2-high) see appendix 2 |
2 |
|
|
2.03 |
Broad climate suitability (environmental versatility) |
y=1, n=0 |
n |
|
2.04 |
Native or naturalized in regions with tropical or subtropical climates |
y=1, n=0 |
y |
|
2.05 |
Does the species have a history of repeated introductions outside its natural range? y=-2 |
?=-1, n=0 |
y |
|
3.01 |
Naturalized beyond native range y = 1*multiplier (see Append 2), n= question 2.05 |
n |
|
|
3.02 |
Garden/amenity/disturbance weed y = 1*multiplier (see Append 2) |
n=0 |
n |
|
3.03 |
Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2) |
n=0 |
n |
|
3.04 |
Environmental weed y = 2*multiplier (see Append 2) |
n=0 |
n |
|
3.05 |
Congeneric weed y = 1*multiplier (see Append 2) |
n=0 |
n |
|
4.01 |
Produces spines, thorns or burrs |
y=1, n=0 |
n |
|
4.02 |
Allelopathic |
y=1, n=0 |
n |
|
4.03 |
Parasitic |
y=1, n=0 |
n |
|
4.04 |
Unpalatable to grazing animals |
y=1, n=-1 |
n |
|
4.05 |
Toxic to animals |
y=1, n=0 |
n |
|
4.06 |
Host for recognized pests and pathogens |
y=1, n=0 |
n |
|
4.07 |
Causes allergies or is otherwise toxic to humans |
y=1, n=0 |
n |
|
4.08 |
Creates a fire hazard in natural ecosystems |
y=1, n=0 |
n |
|
4.09 |
Is a shade tolerant plant at some stage of its life cycle |
y=1, n=0 |
n |
|
4.1 |
Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island) |
y=1, n=0 |
y |
|
4.11 |
Climbing or smothering growth habit |
y=1, n=0 |
n |
|
4.12 |
Forms dense thickets |
y=1, n=0 |
n |
|
5.01 |
Aquatic |
y=5, n=0 |
n |
|
5.02 |
Grass |
y=1, n=0 |
n |
|
5.03 |
Nitrogen fixing woody plant |
y=1, n=0 |
n |
|
5.04 |
Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers) |
y=1, n=0 |
n |
|
6.01 |
Evidence of substantial reproductive failure in native habitat |
y=1, n=0 |
n |
|
6.02 |
Produces viable seed. |
y=1, n=-1 |
y |
|
6.03 |
Hybridizes naturally |
y=1, n=-1 |
|
|
6.04 |
Self-compatible or apomictic |
y=1, n=-1 |
|
|
6.05 |
Requires specialist pollinators |
y=-1, n=0 |
y |
|
6.06 |
Reproduction by vegetative fragmentation |
y=1, n=-1 |
n |
|
6.07 |
Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1 |
See left |
4 |
|
7.01 |
Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas) |
y=1, n=-1 |
n |
|
7.02 |
Propagules dispersed intentionally by people |
y=1, n=-1 |
y |
|
7.03 |
Propagules likely to disperse as a produce contaminant |
y=1, n=-1 |
n |
|
7.04 |
Propagules adapted to wind dispersal |
y=1, n=-1 |
n |
|
7.05 |
Propagules water dispersed |
y=1, n=-1 |
n |
|
7.06 |
Propagules bird dispersed |
y=1, n=-1 |
n |
|
7.07 |
Propagules dispersed by other animals (externally) |
y=1, n=-1 |
n |
|
7.08 |
Propagules survive passage through the gut |
y=1, n=-1 |
y |
|
8.01 |
Prolific seed production (>1000/m2) |
y=1, n=-1 |
n |
|
8.02 |
Evidence that a persistent propagule bank is formed (>1 yr) |
y=1, n=-1 |
|
|
8.03 |
Well controlled by herbicides |
y=-1, n=1 |
|
|
8.04 |
Tolerates, or benefits from, mutilation, cultivation, or fire |
y=1, n=-1 |
|
|
8.05 |
Effective natural enemies present locally (e.g. introduced biocontrol agents) |
y=-1, n=1 |
|
|
Total score: |
-8 |
||
Supporting data:
|
Source |
Notes |
|
|
1.01 |
no evidence |
|
|
1.02 |
no evidence |
|
|
1.03 |
no evidence |
|
|
2.01 |
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/var/apache/cgi-bin/npgs/html/taxon.pl?12209 (23 April 2002) |
Native: |
|
2.02 |
||
|
2.03 |
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/var/apache/cgi-bin/npgs/html/taxon.pl?12209 (23 April 2002) |
Native: |
|
2.04 |
USDA, ARS, National Genetic Resources Program. Germplasm Resources Information Network - (GRIN). [Online Database] National Germplasm Resources Laboratory, Beltsville, Maryland. Available: http://www.ars-grin.gov/var/apache/cgi-bin/npgs/html/taxon.pl?12209 (23 April 2002) |
Native: |
|
2.05 |
(1)Clavo, M.; Vela, J.; Millán, B. (2000) Vegetative
propagation of species used for live fences in pastures at Pucallpa, Peru.
[FT: Propagación vegetativa de especies utilizadas en cercas vivas en
pasturas de Pucallpa, Perú.] Pasturas Tropicales, 2000, Vol.22, No.3,
pp.35-37, 5 ref. |
(1) Peru; (2) India; (3) Hawaii; (4) "widely cult." |
|
3.01 |
no evidence |
|
|
3.02 |
no evidence |
|
|
3.03 |
no evidence |
|
|
3.04 |
no evidence |
|
|
3.05 |
no evidence |
|
|
4.01 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
"no thorns" |
|
4.02 |
no evidence |
|
|
4.03 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
free-living tree |
|
4.04 |
Cajas-Giron-Y-S; Sinclair-F-L. 2001. Characterization of multistrata silvopastoral systems on seasonally dry pastures in the Caribbean region of Colombia.Agroforestry-Systems 53 (2): 215-225.. |
The most important fodder trees were those of mediumstature (Albizia saman, Guazuma ulmifolia, and Cassia grandis) that produced fruits or pods, while other species were managed as shrubs producing green leaf fodder (e.g., Crescentia cujete and Gliricidia sepium, which was also ubiquitous as living fence posts) |
|
4.05 |
http://waynesword.palomar.edu/plmay99.htm#calabash |
It is well documented that horses can break open the hard shell with their mouth and eat the sweet pulpy mass inside |
|
4.06 |
rps.uvi.edu/CES/pmb-hosts.html |
Pink Mealybug - Host plant (generalist pest) |
|
4.07 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
"Fruits are poisonous." but no report of accidental human poisoning |
|
4.08 |
no evidence |
|
|
4.09 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
"Calabash tree should be grown in full sun on any well-drained soil." |
|
4.1 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
"Soil tolerances: clay; loam; sand; acidic; alkaline; well-drained" |
|
4.11 |
no evidence |
|
|
4.12 |
no evidence |
|
|
5.01 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
tree |
|
5.02 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
tree |
|
5.03 |
no evidence |
|
|
5.04 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
tree |
|
6.01 |
no evidence |
|
|
6.02 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
"Propagation is by seed" |
|
6.03 |
no evidence |
|
|
6.04 |
(1) Chauhan, S. V. S.; Veena Yadav; Yadav, D. K.(1987)
Studies into the causes of seedlessness in some Bignoniaceae. Journal of
Experimental Botany, 1987, Vol.38, No.186, pp.173-177, 9 ref. |
[seems to depend on variety](1) AB: A comparative morphological and biochemical study into the causes of seedlessness in some ornamental Bignoniaceae (Campsis grandiflora, Crescentia cujete, Millingtonia hortensis, Pyrostegia venusta and Spathodea campanulata ) revealed that apparently viable pollen grains landing on the stigmatic surface either failed to germinate or tube growth was inhibited. SEM examination showed differences between the stigmatic surface of seedless and seed-bearing plants. The quantity of total phenolics was higher in pistils of seed-bearing plants than in those of seedless plants. These variations were attributed to differences in the environmental conditions; at Agra, where the plants were always seedless, the temperatures were higher and the RH lower than at places such as Bangalore, Jammu and Mysore where the plants were seedbearing. Spathodea pistils from seedless plants cultured at 25 deg C in Nitsch's medium were shown to be capable of forming fruits after artificial pollination |
|
6.05 |
Bestmann, H. J.; Winkler, L.; Helversen, O. von (1997) Headspace analysis of volatile flower scent constituents of bat-pollinated plants. Phytochemistry, 1997, Vol.46, No.7, pp.1169-1172, 7 ref. |
AB: The flower scents of 11 bat-pollinated plant species (originally from the New World, including Cobaea scandens and Crescentia cujete ), growing in 2 University Botanical Gardens in Germany, were investigated using the closed-loop-stripping-adsorption technique. Headspace samples were analysed by GC and GC-MS. A total of 49 compounds were identified, including sulfur compounds, terpenoids and aliphatic compounds. |
|
6.06 |
no evidence |
|
|
6.07 |
R. Criley, UH Department of Horticulture, personal communication |
no evidence |
|
7.01 |
no evidence |
|
|
7.02 |
(1)Clavo, M.; Vela, J.; Millán, B. (2000) Vegetative
propagation of species used for live fences in pastures at Pucallpa, Peru.
[FT: Propagación vegetativa de especies utilizadas en cercas vivas en
pasturas de Pucallpa, Perú.] Pasturas Tropicales, 2000, Vol.22, No.3,
pp.35-37, 5 ref. |
(1) Peru; (2) India; (3) Hawaii; (4) "widely cultivated" |
|
7.03 |
no evidence |
|
|
7.04 |
no evidence |
|
|
7.05 |
no evidence |
|
|
7.06 |
http://waynesword.palomar.edu/plmay99.htm#calabash |
Because the gourds are so large and hard-shelled, no native New Word herbivores can crack them open, and the rotting gourds litter theground beneath old calabash trees. It is well documented that horses can break open the hard shell with their mouth and eat the sweet pulpy mass inside, dispersing the seeds in their dung. |
|
7.07 |
Elias, T. S.; Prance, G. T. (1978) Nectaries on the fruit of Crescentia and other Bignoniaceae. Brittonia, 1978, Vol.30, No.2, pp.175-181, 12 ref. |
AB: Nectar glands are described on the developing fruits of the calabash (Crescentia cujete), and their presence is noted on fruits of 15 other genera of Bignoniaceae from the Amazon Basin. The nectaries are very small, nonvascularized, patelliform structures of epidermal origin which attract ants. It is suggested that the presence of the ants deters herbivores (e.g. monkeys) from eating the fruits. Nectar glands are described for the first time on the developing fruits of Crescentia cujete (calabash tree) and their presence noted on fruits in 15 other genera of the Bignoniaceae. The nectaries are tiny, novascularized, patelliform structures of epidermal origin. They attract ants which are postulated to function in an antiherbivore role. [very large, fleshy fruit] |
|
7.08 |
http://waynesword.palomar.edu/plmay99.htm#calabash |
Because the gourds are so large and hard-shelled, no native New Word herbivores can crack them open, and the rotting gourds litter theground beneath old calabash trees. It is well documented that horses can break open the hard shell with their mouth and eat the sweet pulpy mass inside, dispersing the seeds in their dung. |
|
8.01 |
Gilman, E.F. and D.G.Watson (1993) Crescentia cujete; Calabash-Tree. Fact Sheet ST-216, Environmental Horticulture Department, Florida Cooperative Extension Service, Institute of Food and Agricultural Sciences, University of Florida. |
Fruit |
|
8.02 |
no evidence |
|
|
8.03 |
no evidence |
|
|
8.04 |
no evidence |
|
|
8.05 |
no evidence |
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