Pacific Island Ecosystems at Risk (PIER)


Tagetes minuta


RISK ASSESSMENT RESULTS: High risk, score: 20


Australian/New Zealand Weed Risk Assessment adapted for Hawai‘i.
Information on Risk Assessments
Original risk assessment

Tagetes minuta L. Family - Asteraceae. Common Names(s) - Aztec marigold, dwarf marigold, Khaki-bush, Mexican marigold, muster John Henry, stinking-Roger, wild Marigold, coari-bravo, cravo-bravo, cravo-de-defunto, cravo-de-urubú, cravo_do_mato, erva-fedorenta, rabo-de-foguets, vara-de-rojão, huacatay, chinchilla enana. Synonym(s) - Tagetes glandulifera Schrank, Tagetes glandulosa Link.

Answer

Score

1.01

Is the species highly domesticated?

y=-3, n=0

n

0

1.02

Has the species become naturalized where grown?

y=1, n=-1

1.03

Does the species have weedy races?

y=-1, n=-1

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

y

1

2.04

Native or naturalized in regions with tropical or subtropical climates

y=1, n=0

y

1

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

y

2

3.02

Garden/amenity/disturbance weed y = 1*multiplier (see Append 2)

n=0

y

2

3.03

Agricultural/forestry/horticultural weed y = 2*multiplier (see Append 2)

n=0

y

4

3.04

Environmental weed y = 2*multiplier (see Append 2)

n=0

3.05

Congeneric weed y = 1*multiplier (see Append 2)

n=0

y

2

4.01

Produces spines, thorns or burrs

y=1, n=0

n

0

4.02

Allelopathic

y=1, n=0

y

1

4.03

Parasitic

y=1, n=0

n

0

4.04

Unpalatable to grazing animals

y=1, n=-1

y

1

4.05

Toxic to animals

y=1, n=0

n

0

4.06

Host for recognized pests and pathogens

y=1, n=0

n

0

4.07

Causes allergies or is otherwise toxic to humans

y=1, n=0

n

0

4.08

Creates a fire hazard in natural ecosystems

y=1, n=0

4.09

Is a shade tolerant plant at some stage of its life cycle

y=1, n=0

n

0

4.10

Tolerates a wide range of soil conditions (or limestone conditions if not a volcanic island)

y=1, n=0

y

1

4.11

Climbing or smothering growth habit

y=1, n=0

n

0

4.12

Forms dense thickets

y=1, n=0

y

1

5.01

Aquatic

y=5, n=0

n

0

5.02

Grass

y=1, n=0

n

0

5.03

Nitrogen fixing woody plant

y=1, n=0

n

0

5.04

Geophyte (herbaceous with underground storage organs -- bulbs, corms, or tubers)

y=1, n=0

n

0

6.01

Evidence of substantial reproductive failure in native habitat

y=1, n=0

n

0

6.02

Produces viable seed.

y=1, n=-1

y

1

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

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

n

-1

6.07

Minimum generative time (years) 1 year = 1, 2 or 3 years = 0, 4+ years = -1

See left

1

1

7.01

Propagules likely to be dispersed unintentionally (plants growing in heavily trafficked areas)

y=1, n=-1

y

1

7.02

Propagules dispersed intentionally by people

y=1, n=-1

y

1

7.03

Propagules likely to disperse as a produce contaminant

y=1, n=-1

y

1

7.04

Propagules adapted to wind dispersal

y=1, n=-1

y

1

7.05

Propagules water dispersed

y=1, n=-1

n

-1

7.06

Propagules bird dispersed

y=1, n=-1

n

-1

7.07

Propagules dispersed by other animals (externally)

y=1, n=-1

y

1

7.08

Propagules survive passage through the gut

y=1, n=-1

n

-1

8.01

Prolific seed production (>1000/m2)

y=1, n=-1

y

1

8.02

Evidence that a persistent propagule bank is formed (>1 yr)

y=1, n=-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

y

1

8.05

Effective natural enemies present locally (e.g. introduced biocontrol agents)

y=-1, n=1

Total score:

20

Supporting data:

Notes

Source

1.01

(1) Cultivation practices were developed by the Natural Plant Products Division of the Institute of Himalayan Bioresource Technology to grow wild Tagetes minuta as an essential oil crop. The study developed four cropping systems based on variable sowing and harvesting times to yield varying quality of essential oil. Commercial production of Tagetes minuta essential oil was limited to wild growth prior to this extension work during 1989-1996.

(1) Singh, V., B. Singh, et al. (2003). "Domestication of Wild Marigold (Tagetes minuta L.) as a Potential Economic Crop in Western Himalaya and North Indian Plains." Economic Botany 57(4): 535-544.

1.02

1.03

2.01

(1) Native to Brazil, Bolivia, Ecuador, Argentina, Chile, Paraguay, Uruguay

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36201[cited 2009 march 5].

2.02

(1) Native to Brazil, Bolivia, Ecuador, Argentina, Chile, Paraguay, Uruguay

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36201[cited 2009 march 5].

2.03

(1) Tagetes minuta is abundant at high and low altitudes, and in high or low rainfall conditions.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

2.04

(1) Native to Brazil, Bolivia, Ecuador, Argentina, Chile, Paraguay, Uruguay. Naturalized in Europe, Africa, Asia, Australia, New Zealand, United States (including Hawaii), Macaronesia, and Madagascar.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36201[cited 2009 march 5].

2.05

(1) Widely cultivated. Naturalized in Europe, Africa, Asia, Australia, New Zealand, United States (including Hawaii), Macaronesia, and Madagascar.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36201[cited 2009 march 5].

3.01

(1) Naturalized in Europe, Africa, Asia, Australia, New Zealand, United States (including Hawaii), Macaronesia, and Madagascar.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36201[cited 2009 march 5].

3.02

(1) The species establishes readily in disturbed sites. (2) "Tagetes minuta is often found growing in disturbed areas during early successional stages. This affinity for disturbed sites has allowed the species to colonize many areas around the world."

(1) Weber, E. 2003. Invasive Plants of the World: A Reference Guide to Environmental Weeds. CABI Publishing, Oxford, UK. (2) http://www.hort.purdue.edu/newcrop/proceedings1993/V2-649.html [cited 2009 March 6].

3.03

(1) Tagetes minuta Is a weed of 19 crops in 35 countries. It is a serious weed of beans in Keny and South Africa; cotton in Brazil, Hawaii, and Zimbabwe. Maize in Argentina, Guatemala, South Africa, Uruguay and Zambia; pastures in Australia, brazil, Hawaii, and Zimbabwe; pyrethrum in Kenya and Tanzania; sorghum and soybeans in South Africa; sunflowers in Argentina; vegetables in Brazil and South Africa; wheat in Guatemala and South Africa; and wastelands in Brazil.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

3.04

(1) The large size and dense growth makes it highly competitive to native plant species.

(1) Weber, E. 2003. Invasive Plants of the World: A Reference Guide to Environmental Weeds. CABI Publishing, Oxford, UK.

3.05

(1) Tagetes erecta is considered and invasive alien species in India.

(1) Reddy C.S., Bagyanarayana G., Reddy K.N., Raju V.S. 2008. Invasive Alien Flora of India. National Biological Information Infrastructure, USGS. USA.

4.01

(1) No spines, thorns or burrs.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

4.02

(1) Field study used dried leaf powder of Tagetes minuta as a mulch to suppress the growth of two rice paddy weeds, Echinochloa crus-galli and Cyperus rotundus. The powder significantly reduced the growth and emergence of both weeds and significantly increased the rice yield.

(1) Batish, D. R., K. Arora, et al. (2007). "Potential utilization of dried powder of Tagetes minuta as a natural herbicide for managing rice weeds." Crop Protection 26(4): 566-571.

4.03

(1) Not parasitic.

4.04

(1) Tagetes minuta has secondary metabolites that prevent herbivory.

(1) Martinez-Ghersa, M. A., C. M. Ghersa, et al. (2000). "Adaptive traits regulating dormancy and germination of invasive species." Plant Species Biology 15(2): 127-137.

4.05

(1) No evidence of toxicity in PubMed. (2) No evidence of toxicity in Toxnet.

(1) http://www.ncbi.nlm.nih.gov/sites/entrez [cited 2009 March 6]. (2) http://toxnet.nlm.nih.gov/cgi-bin/sis/search/d?./temp/~AM7L7H:20:@sa [cited 2009 March 6].

4.06

(1) Tagetes minuta can host bean fungus (Ascochyta phaseolorum) under natural conditions in Australia. (2) T. minuta is generally free from insects and other pests and diseases. Occasionally, a crop is infected with viruses during the rainy season. (3) Pests are not a significant problem of Tagetes minuta in field culture.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827. (2) Singh, V., B. Singh, et al. (2003). "Domestication of Wild Marigold (Tagetes minuta L.) as a Potential Economic Crop in Western Himalaya and North Indian Plains." Economic Botany 57(4): 535-544. (3) http://www.hort.purdue.edu/newcrop/proceedings1993/V2-649.html [cited 2009 March 6].

4.07

(1) Tagetes minuta has been used as a relish, laxative, diuretic, flavoring, insect repellent, stimulant, and snuff. In parts of Peru it is used as a vegetable called "huacatay". It is among the vegetables with the highest levels of vitamin C. (2) T. minuta is used in medicinal tea and in condiments since early times. The oil is used for high grade perfumes and in the flavor industry. (3) No evidence of toxicity in PubMed.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827. (2) Singh, V., B. Singh, et al. (2003). "Domestication of Wild Marigold (Tagetes minuta L.) as a Potential Economic Crop in Western Himalaya and North Indian Plains." Economic Botany 57(4): 535-544. (3) http://www.ncbi.nlm.nih.gov/sites/entrez [cited 2009 March 6].

4.08

Unknown. No information on fire hazard was found.

 

4.09

(1) Tagetes minuta thrives in full sun.

(1) http://www.hort.purdue.edu/newcrop/proceedings1993/V2-649.html [cited 2009 March 6].

4.10

(1) Tolerates soil pH from 4.3 to 6.6. (2) T. minuta prefers slightly acidic soil (pH = 5.5 to 7.0) and a well-drained sandy loam to clay loam.

(1) Motooka P., C. L., Nelson D., Nagai G., Ching L. (2003). Weeds of Hawaii's Pastures and Natural Areas. Honolulu, College of Tropical Agriculture and Human Resources University of Hawaii at Manoa. (2) Singh, V., B. Singh, et al. (2003). "Domestication of Wild Marigold (Tagetes minuta L.) as a Potential Economic Crop in Western Himalaya and North Indian Plains." Economic Botany 57(4): 535-544.

4.11

(1) Annual herb growing to 120 cm or more tall.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

4.12

(1) In Hawaii, Tagetes minuta has not yet formed dense stand that are reported elsewhere. Reports from other areas in the world indicate that it can become dominant. (2) Can form dense populations after a fire or when forests are cut and burned.

(1) Motooka P., C. L., Nelson D., Nagai G., Ching L. (2003). Weeds of Hawaii's Pastures and Natural Areas. Honolulu, College of Tropical Agriculture and Human Resources University of Hawaii at Manoa. (2) Weber, E. 2003. Invasive Plants of the World: A Reference Guide to Environmental Weeds. CABI Publishing, Oxford, UK.

5.01

(1) Terrestrial

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

5.02

(1) Asteraceae.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

5.03

(1) Herbaceous annual. Asteraceae.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

5.04

(1) No underground storage units.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

6.01

No evidence.

 

6.02

(1) Seeds achieve maximum germination at 25° C. None germinate at 10 or 35° C even when in the light. The optimal germination range is narrow. Germination of fresh seed was as high as 95%.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

6.03

Unknown (1) There has been extensive horticultural selection and hybridization in the Tagetes genus for the horticultural trade.

(1) Staples, G. W., Herbst, D.R. (2005). A Tropical Garden Flora Plants Cultivated in the Hawaiian Islands and Other Tropical Places. Honolulu, Bishop Museum Press.

6.04

Unknown

6.05

(1) Inflorescence heads numerous, usually flat-topped cymes; involucre cylindrical, 8-12 mm high, apex 3-5 toothed; ray flortes usually 3 per head, Rays 1-2 mm long; disk florets usually 3-5 per head, corollas ca. 2.5 mm long.

(1) Wagner W.L., H. D. R., Sohmer S.H. (1999). Manual of the Flowering Plants of Hawaii. Honolulu Bishop Museum Press.

6.06

(1) No evidence of vegetative reproduction. Annual.

(1) Wagner W.L., H. D. R., Sohmer S.H. (1999). Manual of the Flowering Plants of Hawaii. Honolulu Bishop Museum Press.

6.07

(1) Summer annual.

(1) Martinez-Ghersa, M. A., C. M. Ghersa, et al. (2000). "Adaptive traits regulating dormancy and germination of invasive species." Plant Species Biology 15(2): 127-137.

7.01

(1) Tagetes minuta seeds are dispersed by combines in agricultural fields.

(1) Martinez-Ghersa, M. A., C. M. Ghersa, et al. (2000). "Adaptive traits regulating dormancy and germination of invasive species." Plant Species Biology 15(2): 127-137.

7.02

(1) Widely cultivated. Naturalized in Europe, Africa, Asia, Australia, New Zealand, United States (including Hawaii), Macaronesia, and Madagascar. (2) Tagetes minuta is highly valued for its essential oil. Due to high demand of its essential oil, there has been increasing interest in the cultivation of this plant for commercial production.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36201[cited 2009 march 5]. (2) Singh, V., B. Singh, et al. (2003). "Domestication of Wild Marigold (Tagetes minuta L.) as a Potential Economic Crop in Western Himalaya and North Indian Plains." Economic Botany 57(4): 535-544.

7.03

(1) Tagetes minuta seed can be transported as a contaminant of crop seed. In Kenya, 44% of the wheat samples examined contained seeds of Tagetes minuta.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

7.04

(1) Wind dispersed.

(1) Lloret, F., F. Medail, et al. (2005). "Species attributes and invasion success by alien plants on Mediterranean islands." Journal of Ecology 93(3): 512-520.

7.05

(1) Achene flattened, 6-8 mm long, pappus scales 2-3 mm long

(1) Wagner W.L., H. D. R., Sohmer S.H. (1999). Manual of the Flowering Plants of Hawaii. Honolulu Bishop Museum Press.

7.06

(1) Achene flattened, 6-8 mm long, pappus scales 2-3 mm long

(1) Wagner W.L., H. D. R., Sohmer S.H. (1999). Manual of the Flowering Plants of Hawaii. Honolulu Bishop Museum Press.

7.07

(1) Seeds are dispersed by attaching to animals. (2) Tagetes minuta produces small seeds with hooks that aid in animal dispersal.

(1) Weber, E. 2003. Invasive Plants of the World: A Reference Guide to Environmental Weeds. CABI Publishing, Oxford, UK. (2) Martinez-Ghersa, M. A., C. M. Ghersa, et al. (2000). "Adaptive traits regulating dormancy and germination of invasive species." Plant Species Biology 15(2): 127-137.

7.08

[not ingested]

 

8.01

(1) In Zimbabwe, 20 plants produced an average of 29,100 seeds each. (2) Each plant can produce over 29,000 seeds of which 95% are viable.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827. (2) Motooka P., C. L., Nelson D., Nagai G., Ching L. (2003). Weeds of Hawaii's Pastures and Natural Areas. Honolulu, College of Tropical Agriculture and Human Resources University of Hawaii at Manoa.

8.02

(1) Tagetes minuta does not have a persistent seed bank.

(1) Martinez-Ghersa, M. A., C. M. Ghersa, et al. (2000). "Adaptive traits regulating dormancy and germination of invasive species." Plant Species Biology 15(2): 127-137.

8.03

Unknown (1) An effective herbicide for control is paraquat.

(1) http://www.hear.org/Pier/species/Tagetes_minuta.htm [cited 2009 March 6].

8.04

(1) Tagetes minuta is prevalent in East and South Africa and can reach dense populations after a fire or when forests are cut and burned.

(1) Holm L., D. J., Holm E., Pancho J., Herberger J. (1997). Tagetes minuta L. Asteraceae (Compositae) Aster Family. World Weeds: Natural Histories and Distribution. New York, John Wiley & Sons, Inc.: 822-827.

8.05

Unknown


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