Pacific Island Ecosystems at Risk (PIER)


Tithonia diversifolia


RISK ASSESSMENT RESULTS: High risk, score: 17


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

Tithonia diversifolia (Hemsl.) A. Gray Family - Asteraceae. Common Names(s) - Mexican sunflower, Mexikaanse sonneblom, shrub-sunflower Synonym(s) - Mirasolia diversifolia

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

n

-1

4.05

Toxic to animals

y=1, n=0

n

0

4.06

Host for recognized pests and pathogens

y=1, 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

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

n

-1

6.05

Requires specialist pollinators

y=-1, n=0

n

0

6.06

Reproduction by vegetative fragmentation

y=1, n=-1

y

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

7.08

Propagules survive passage through the gut

y=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

y

-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:

17

Supporting data:

Notes

Source

1.01

No evidence.

 

1.02

1.03

2.01

(1) Native to Mexico; Belize; Costa Rica; El Salvador; Guatemala; Honduras; Nicaragua; Panama

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36733#syn [Cited 2009 October 20].

2.02

(1) Native to Mexico; Belize; Costa Rica; El Salvador; Guatemala; Honduras; Nicaragua; Panama

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36733#syn [Cited 2009 October 20].

2.03

(1) USDA Hardiness zones: 9-11. Light frosts and freezes with kill T. diversifolia to the ground, by if the damage is not too bad they will resprout in the spring. (2) USDA hardiness zones: 9a - 10b. (3) T. diversifolia is adapted to all the ecological zones of southwestern Nigeria, which include evergreen forest to southern Guinea savanna. (4) In South Africa, T. diversifolia occurs at altitudes of 0 - 600 m. (4) Tithonia diversifolia is distributed along farm boundaries in humid and subhumid tropics of Africa, generally at elevations between 500 and 2000 m.

(1) http://www.floridata.com/ref/t/tith_div.cfm [Cited 2009 October 26] (2) http://davesgarden.com/guides/pf/go/59827/ [Cited 2009 October 26]. (3)Ayeni, A.O., Lordbanjou, D.T., Majek, B.A., 1997. Tithonia diversifolia (Mexican sunflower) in south-western Nigeria: occurrence and growth habit. Weed Research 37, 443-449.(4) http://www.sabonet.org.za/aliens/aliens_part3_asteraceae.htm [Cited 2009 October 26]. (4) http://books.google.com/books?id=0oP_0c-MjNEC&pg=PA33&lpg=PA33&dq=tithonia+diversifolia+%2B+%22soil%22&source=bl&ots=zBJEcyElG4&sig=
d3o4oLXo8dgAXWXnYj7Z7RytAeE&hl=en&ei=mF7mSrjsKYyuswO88MmwBQ&sa=X&oi=book_result&ct
=result&resnum=1&ved=0CAwQ6AEwADgK#v=onepage&q=tithonia%20diversifolia%20%2B%20%22soil%22&f=false [Cited 2009 October 26].

2.04

(1) Native to Mexico; Belize; Costa Rica; El Salvador; Guatemala; Honduras; Nicaragua; Panama

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36733#syn [Cited 2009 October 20].

2.05

(1) In West Africa, Tithonia diversifolia was introduced as an ornamental plant and with imported grains (contaminant). (2) Tithonia diversifolia was introduced to Nigeria in the 1960's for use as a green manure. (3) Introduced to many Pacific islands (Hawaii, Guam, New Caledonia, French Polynesia, Palau, etc.) and some Indian Ocean islands (Christmas Island, La Réunion and Mauritius)

(1) Muoghalu, J.I., 2008. Growth, reproduction and resource allocation of Tithonia diversifolia and Tithonia rotundifolia. Weed Research 48.

(2) Ayeni, A.O., Lordbanjou, D.T., Majek, B.A., 1997. Tithonia diversifolia (Mexican sunflower) in south-western Nigeria: occurrence and growth habit. Weed Research 37, 443-449. (3) http://www.issg.org/database/species/ecology.asp?si=1320&fr=1&sts=&lang=EN [Cited 2009 October 26].

3.01

(1) Naturalized throughout the tropics and subtropics. (2) Tithonia diversifolia is naturalized in South Africa and West Africa.

(1) http://www.ars-grin.gov/cgi-bin/npgs/html/taxon.pl?36733#syn [Cited 2009 October 20]. (2) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46.

3.02

(1) Tithonia diversifolia is a serious weed of arable crops, plantations, abandoned lawns and roadsides. It is an aggressive colonizer on new sites that are sunny and have a high water table. (2) Tithonia diversifolia can invade disturbed habitats. Dense shading below the plant inhibits growth of native seedlings.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46. (2) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009 October 26

3.03

(1) Tithonia diversifolia is a serious weed of arable crops, plantations, abandoned lawns and roadsides. It is an aggressive colonizer on new sites that are sunny and have a high water table. (2) Can invade agricultural land, competing with crop plants. (3) Tithonia diversifolia has forced many farmers to abandon their farmland in southwestern Nigeria.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46. (2) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009 October 26]. (3) Ayeni, A.O., Lordbanjou, D.T., Majek, B.A., 1997. Tithonia diversifolia (Mexican sunflower) in south-western Nigeria: occurrence and growth habit. Weed Research 37, 443-449.

3.04

(1) Tithonia diversifolia is a serious weed of arable crops, plantations, abandoned lawns and roadsides. It is an aggressive colonizer on new sites that are sunny and have a high water table. T. diversifolia displaces native species in areas that it grows. (2) Allelopathic. Shades out native seedlings.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46. (2) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009 October 26].

3.05

(1) Tithonia rotundifolia Is an invasive weed in parts of Africa. T. rotundifolia is a serious weed of arable crops, plantations, abandoned lawns and roadsides. It is an aggressive colonizer of new sites that have high light and adequate moisture.

(1) Muoghalu, J.I., 2008. Growth, reproduction and resource allocation of Tithonia diversifolia and Tithonia rotundifolia. Weed Research 48.

4.01

(1) No spines, thorns, burrs.

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

4.02

(1) "Seed germination, shoot growth and root growth of radish, rice, sorghum, crabgrass, rice flat sedge and slender amaranth in soil from the field which had been planted with Mexican sunflower for 5 years were less in degree than those in the soil from the area without Mexican sunflower (Table 1). The property of soil with this plant was the same as that from the areas without the plants, as described above. This result demonstrated that soil planted with Mexican sunflower for 5 years under water stress conditions during the summer in northern Thailand, has phytotoxic activity under natural conditions, and suggested that the soil contains allelopathic substance(s) in amounts sufficient to suppress germination and seedling growth of other plant species."

(1) Tongma, S., Kobayashi, K., Usui, K., 2001. Allelopathic activity of Mexican sunflower (Tithonia diversifolia (Hemsl.) A. Gray) in soil under natural field conditions and different moisture conditions. Weed Biology and Management 1, 115-119.

4.03

(1) Not parasitic.

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

4.04

(1) Tithonia diversifolia is one of the major non-leguminous forages used as fodder for cattle in India. It is also used as an indigenous medicine for cattle. (2) In south-western Nigeria, Tithonia diversifolia is browsed by nomadic and village cattle, sheep and goats.

(1) Perera, A.N.F., Perera, E.R.K.2006. Evaluation of lesser-known feeds for ruminants to improve and sustain animal productivity during dry periods. In: Improving Animal Productivity by Supplementary Feeding of Multinutrient Blocks, Controlling Internal Parasites and Enhancing Utilization of Alternate Feed Resources. IAEA-TecDoc-1495. Vienna, Australia. Animal Production and Health Section. Joint FAO?IAEA Division. International Atomic Energy Agency. (2) Akinola, J.O., LarbiI, A., Farinu, G.O., Odunsi, A.A., 2000. Seed treatment methods and duration effects on germination of wild sunflower. Experimental Agriculture 36, 63-69.

4.05

(1) Tithonia diversifolia is one of the major non-leguminous forages used as fodder for cattle in India. It is also used as an indigenous medicine for cattle. (2) In south-western Nigeria, Tithonia diversifolia is browsed by nomadic and village cattle, sheep and goats.

(1) Perera, A.N.F., Perera, E.R.K.2006. Evaluation of lesser-known feeds for ruminants to improve and sustain animal productivity during dry periods. In: Improving Animal Productivity by Supplementary Feeding of Multinutrient Blocks, Controlling Internal Parasites and Enhancing Utilization of Alternate Feed Resources. IAEA-TecDoc-1495. Vienna, Australia. Animal Production and Health Section. Joint FAO?IAEA Division. International Atomic Energy Agency. (2) Akinola, J.O., LarbiI, A., Farinu, G.O., Odunsi, A.A., 2000. Seed treatment methods and duration effects on germination of wild sunflower. Experimental Agriculture 36, 63-69.

4.06

Unknown

4.07

(1) No evidence of toxicity I PubMed. (2) No evidence of allergies or toxicity in ToxNet.

(1) http://www.ncbi.nlm.nih.gov/sites/entrez [Cited 2009 October 26] (2) http://toxnet.nlm.nih.gov/cgi-bin/sis/search [Cited 2009 October 26].

4.08

Unknown

4.09

(1) Shade intolerant, requires full sun.

(1) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009 October 26].

4.10

(1) Tithonia diversifolia was grown in Maseno soils (acid with clay texture) in Kenya to assess biomass production over a 6 month period. The soils are classified as Humic Nitosols based on the FAO?UNESCO System, equivalent to kaolinitic, isohypertermic Typic Kanhaplohumults in the USDA soil taxonomy system. Tithonia is able to mine phosphorus from the soil. Its leaves have a high concentration of nitrogen. (2) Rich well-drained soil.

(1) Rutunga, V., Karanja, N.K., Gachene, G.K.K., Palm, C., 1999. Biomass production and nutrient accumulation by Tephosia vogelii (Hemsley) A. Gray and Tithonia diversifolia Hook F. fallows during the six-month growth period at Maseno, Western Kenya. "Biotechnology, Agronomy, Society and Environment" 3, 237-246.(2) http://www.ecrater.com/product.php?pid=5779008 [Cited 2009 October 26].

4.11

(1) Shrubs 2-5 m tall

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

4.12

(1) T. diversifolia forms dense stands along roadsides, river banks and in wasteland.

(1) http://www.sabonet.org.za/aliens/aliens_part3_asteraceae.htm [Cited 2009 October 26]

5.01

(1) Shrubs 2-5 m tall

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

5.02

(1) Asteraceae. Shrubs 2-5 m tall.

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

5.03

(1) Tithonia diversifolia's leaves have a high nitrogen content. It is thought that the roots of Tithonia diversifolia may be associated with mycorrhizoral fungi

(1) http://nzdl.sadl.uleth.ca/cgi-bin/library.cgi?e=d-00000-00---off-0hdl--00-0----0-10-0---0---0direct-10---4-------0-1l--11-en-50---20-about---00-0-1-00-0-0-11-1-0utfZz-8-00&a=d&cl=CL3.6&d=HASH0185633f1c7677c2a64ded88.4 [Cited 2009 October 26]

5.04

(1) Shrubs 2-5 m tall

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

6.01

No evidence.

 

6.02

(1) Tithonia diversifolia reproduces by seed and by vegetative regrowth when the stem is cut.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46.

6.03

Unknown

6.04

(1) Evidence indicates that effective apomixis is absent in the genus Tithonia.

(1) Noyes, R.D., 2007. Apomixis in the Asteraceae: diamonds in the rough. Functional Plant Science and Biotechnology 1, 207-222.

6.05

(1) The nectar and pollen of T. diversifolia is very attractive to honeybees.

(1) http://www.fshs.org/Proceedings/Password%20Protected/1964%20Vol.%2077/415-436%20(MORTON).pdf [Cited 2009 October 26].

6.06

(1) Tithonia diversifolia reproduces by seed and by vegetative regrowth when the stem is cut.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46.

6.07

(1) Tithonia diversifolia grows as an annual or perennial in Nigeria. In undisturbed environment and upland conditions it behaves as an annual. In areas with a high water table and when slashed, it behaves as a perennial. Tithonia can germinate and produce seed in one year.

(1) Ayeni, A.O., Lordbanjou, D.T., Majek, B.A., 1997. Tithonia diversifolia (Mexican sunflower) in south-western Nigeria: occurrence and growth habit. Weed Research 37, 443-449.

7.01

(1) Tithonia diversifolia is a serious weed of arable crops, plantations, abandoned lawns and roadsides (2) Tithonia diversifolia produces 134,451.75 ± 49,792.14 seeds per plant. (3) Pappus of 2 persistent awns ca. 5 mm long. Achenes flattened, ca. 5 mm long.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46. (2) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46. (3)Wagner, W.L., Herbst, D.R., Sohmer, S.H., 1999. Manual of the Flowering Plants of Hawaii. Bishop Museum Press, Honolulu.

7.02

(1) T. diversifolia is grown as an ornamental in Hawaii, where it has naturalized. It has also naturalized in many tropical and warm countries of the old world. (2) Tithonia diversifolia is used as a green manure in Africa and Asia. This species has the ability to mine phosphorus from the soil and provide this element for crop growth. (3) T. diversifolia was introduced to the island of Ceylon in the late 1800's.

(1) Staples, G.S.H., D.R., 2005. A Tropical Garden Flora. Bishop Museum Press, Honolulu. (2) Sangakkara, U.R., Liedgens, M., Soldati, A., Stamp, P., 2004. Root and shoot growth of maize (Zea mays) as affected by incorporation of Crotalaria juncea and Tithonia diversifolia as green manures. Journal of agronomy and crop science = Zeitschrift fur Acker- und Pflanzenbau 190, 339-346 (3) http://books.google.com/books?id=FZwSAAAAYAAJ&pg=PA786&lpg=PA786&dq=Tithonia+diversifolia
+%2B+%22dispersal%22&source=bl&ots=fN9vbUqjDx&sig=1NIzkhWSHZpYj7dtWmHz6L9rgBU&hl=en&ei=
gkbmSocOhLazA72fwbAE&sa=X&oi=book_result&ct=result&resnum=5&ved=0CBoQ6AEwBA#v=onepage&q=
Tithonia%20diversifolia%20%2B%20%22dispersal%22&f=false [Cited 2009 October 26].

7.03

(1) Tithonia diversifolia is used as a green manure in Africa and Asia. This species has the ability to mine phosphorus from the soil and provide this element for crop growth. (2) T. diversifolia is thought to have been introduced to Nigeria as a produce contaminant in seeds of Zea mays imported from Israel.

(1) Sangakkara, U.R., Liedgens, M., Soldati, A., Stamp, P., 2004. Root and shoot growth of maize (Zea mays) as affected by incorporation of Crotalaria juncea and Tithonia diversifolia as green manures. Journal of agronomy and crop science = Zeitschrift fur Acker- und Pflanzenbau 190, 339-346. (2) Chukwuka, K.S., Ogunyemi, S., Fawole, I., 2007. Ecological distribution of Tithonia diversifolia (Hemsl). A. Gray - a new exotic weed in Nigeria. Journal of Biological Sciences 7, 709-719.

7.04

(1) Pappus of 2 persistent awns ca. 5 mm long. Achenes flattened, ca. 5 mm long.

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

7.05

[No adaptation for water dispersal]. (1) Pappus of 2 persistent awns ca. 5 mm long. Achenes flattened, ca. 5 mm long. [known to form dense stands along riparian areas].

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

7.06

(1) Pappus of 2 persistent awns ca. 5 mm long. Achenes flattened, ca. 5 mm long.

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

7.07

Unknown (1) Pappus of 2 persistent awns ca. 5 mm long. Achenes flattened, ca. 5 mm long. [persistent awns could possibly attach to animals]

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

7.08

Unknown

8.01

(1) Tithonia diversifolia produces 134,451.75 ± 49,792.14 seeds per plant.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46.

8.02

(1) Seeds can be dormant for up to four months.

(1) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009 October 26].

8.03

(1) In this field experiment, a preemergence application of imazethapyr-pendimethalin mixture at 0.09 + 1.31 kg/ha (equivalent to 4L/ha commercial product) was an effective control of Tithonia diversifolia. (2) Triclopyr (300g/L) and picloram (100g/L) at 350 millilitres per 100 litres water as foliar spray; mesulfuron-methyl (600g/L) at 10 grams per 100 litres water plus wetting agent applied as spot spray; 2,4-D amine (500g/L) at 4 millilitres per 1 litre water or 2,4-D amine (625 g/L) at 3 millilitres per 1 litre water applied as spot spray; 1.5% glyphosate in water are effective herbicides for control of Tithonia diversifolia.

(1) Ayeni, A.O., Agbato, S.O., Majek, B.A., 1997. Seed Depth Influence on Mexican Sunflower (Tithonia diversifolia) Emergence and Control. Weed Technology 11, 417-427.(2) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009

8.04

(1) Tithonia diversifolia coppices profusely when the stem is cut. (2) Manual cutting of larger plants is ineffective as T. diversifolia coppices profusely.

(1) Muoghalu, J.I., Chuba, D.K. 2005. Seed germination and reproductive strategies of Tithonia diversifolia (Hemsl.) Gray and Tithonia rotundifolia (P.M.) Blake. Applied Ecology and Environmental Research 3 (1):39-46.(2) http://www.tropical-biology.org/research/dip/species/Tithonia%20diversifolia.htm [Cited 2009 October 26].

8.05

Unknown


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