Parthenium hysterophorus L.

Title: Parthenium hysterophorus L.

Scientific Name:

Parthenium hysterophorus L.

Common Name:

parthenium weed

Source & more images (via ALA)

Habitat: Disturbed sites, roadsides, railway reserves, stockyard, cultivated fields, run-down pastures and vacant lots (WAR). Grazing land (Agfact). Colonises weak pastures, water points. Can also colonise brigalow, gidgee and softwood scrubsoils. (NRM facts). Potential to become problem in cropping areas (Nox weeds), intolerant heavy shading. Doesn’t compete with established perennial grasses. All types of crops, orchardsland, pastures, forest nurseries, public lawns and open spaces in towns, railways, roadsides, new construction sites streams and rivers.

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? “Seeds germinate at any time of year provided moisture is available” (Parsons, Cuthbertson 2001) – Opportunistic germinator.

2. Establishment requirements? “Seeds exposed to light showed higher germination than those in darkness but with time this difference tended to become smaller” (Tamado et al 2002) – Can establish without additional factors.

3. How much disturbance is required? “It occurs as a weed in disturbed areas on roadsides, railway reserves, stock yards, cultivated fields, run-down pastures and vacant lots” (Parsons, Cuthbertson 2001). “Parthenium does not compete with established perennial grasses as it requires bare soil to germinate” (McFadyen 1992) – Requires some disturbance or bare soil to establish.

GROWTH / COMPETITIVE

4. Life form? Short-lived annual (McFadyen 1992) – Other.

5. Allelopathic properties? This constitutes the first report of pollen allelopathy and, such is the production of pollen, estimated at 3375 ´ 106 grains/m2 (Kanchan & Jayachandra, 1980b) or 624 ´ 106 grains/plant (Towers & Subba Rao, 1992), that the negative effects on the crop within the infested fields, as well as in neighbouring weed-free crops, may be significant……..The allelopathic nature of P. hysterophorus has been well documented.” It is known to inhibit the germination of a large number of trees, shrubs and crops. Examples of such species are Casuarina, Acacia, Eucalyptus, rice, wheat, barley mung beans and sorghum (Evans 1997) – Major allelopathic properties inhibiting the growth of many or all plants.

6. Tolerates herb pressure? “Livestock do not normally eat the weed but hungry animals, particularly sheep, may do so if nothing else is available” (Parsons, Cuthbertson 2001). “Under continued grazing pressure, parthenium weed will completely dominate the pasture, forming pure stands over areas up to 5000 hectares.” However biological control agents have been released since 1975 in Australia, the most successful being a moth larvae (Epiblema strenuana). It forms galls on the stems and shoots which results in stunted plants and reduces seeds production (McFadyen 1992) – Under biological control, however this is not known to occur in Victoria.

7. Normal growth rate? “…plants commence flowering within 4 to 8 weeks of germination, 4 weeks being more likely in dry periods” (Parsons, Cuthbertson 2001) – Rapid growth to flowering stage likely to exceed the growth rate of similar species.

8. Stress tolerance to frost, drought, w/logg, sal. etc? “Flowering… continues until drought or frost kills the plant” (McFadyen 1992) – Not tolerant to either drought or frost. Has a salinity limit of 20 dS m-1 (Alsharhan, Alsharhan 2003) – tolerance to slight salinity. “Fire does not significantly reduce the germinable soil seed bank of parthenium… nor does smoke… stimulate parthenium seed germination. Fire did however result in one-off increases in parthenium densities, which after subsequent fires rapidly declined” (Vogler et al 2006) – fire tolerant.

REPRODUCTION

9. Reproductive system? Annual herb, reproducing by seed. “Self-compatibility of parthenium weed has not been observed in plants grown in isolation in Australia.” (Navie et al 1998) – Cross-pollination only.

10. Number of propagules produced? “Parthenium weed seeds prolifically, each plant producing about 15000 seeds” (Parsons, Cuthbertson 2001) – Above 2000 seeds produced annually.

11. Propagule longevity? “Some field evidence exists that parthenium weed achenes can remain viable after being buried for at least 4–6 years” (Navie et al 1998) – Greater than 25% of seeds survive 5-10 years in the soil.

12. Reproductive period? Short-lived annual. Produces propagules for one growing season (McFadyen 1992) – mature plant produces viable propagules for only 1 year.

13. Time to reproductive maturity? Plant commences flowering within 4 to 8 weeks of germination (Parsons, Cuthbertson 2001) – reaches maturity and produces viable propagules in under one year.

DISPERSAL

14. Number of mechanisms? “Dispersal of parthenium weed achenes occurs locally by wind and water. Wind transport is usually only in the order of a few metres” (Navie et al 1998). “Most of the really long-distance spread is by animals, vehicles, farm machinery, and in mud” (Parsons, Cuthbertson 2001).

15. How far do they disperse? “In the majority of cases of long distance dispersal, achenes are transported on motor vehicles or machinery, on livestock, with crop and pasture seed, or in fodder. As a result, new infestations of the weed may appear thousands of kilometres from the nearest plants” (Navie et al 1998) – very likely that at least one propagule will disperse greater than one kilometre.

Impact Assessment

RECREATION

1. Restrict human access? An erect annual herb 30 cm to 150 cm high. “…an aggressive coloniser of fallows, wasteland, roadsides, and overgrazed pastures” (Parsons, Cuthbertson 2001). Dense infestations may impede individual access, though not seriously – low nuisance value; impedes individual access.

2. Reduce tourism? As it grows to 150cm and forms pure stands (Parsons, Cuthbertson 2001) it may have some impact on aesthetics.

3. Injurious to people? More than two decades ago, serious human health risks from P. hysterophorus were reported from India, and 12 deaths were attributed to allergenic responses. (Evans 1997) “Regular contact with the plant, usually over a prolonged period, produces an acute form of dermatitis, and asthma in humans” (Parsons, Cuthbertson 2001) – Potentially harmful for most of the year.

4. Damage to cultural sites? As it grows to 150cm and forms pure stands (Parsons, Cuthbertson 2001) it may have a moderate visual effect on cultural sites.

ABIOTIC

5. Impact flow? Terrestrial species (Parsons, Cuthbertson 2001) – not likely to impact flow.

6. Impact water quality? Terrestrial species (Parsons, Cuthbertson 2001) – not likely to impact water quality.

7. Increase soil erosion? “Parthenium weed becomes established in disturbed, degraded or bare soil. In good conditions Parthenium weed can germinate, flower and set seed within four weeks” (Trounce 1998) Vigorous growth would provide some protection against erosion.

8. Reduce biomass? “Parthenium weed becomes established in disturbed, degraded or bare soil.” Likely to increase biomass. Trounce (1998).

9. Change fire regime? Although the woody stems remain after the plant dies, there would be insufficient fuel to support fire (Bob Trounce pers comm) - negligible effect on fire risk.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC = Riverine Grassy Woodland (V); CMA = North Central; Bioregion = Murray Fans; VH CLIMATE potential. An erect annual herb 30 cm to 150 cm high. “…an aggressive coloniser of fallows, wasteland, roadsides, and overgrazed pastures” (Parsons, Cuthbertson 2001). Monoculture within a specific layer; displaces all species within a strata.

10(b) Impact on medium value EVC? EVC = Lake Bed Herbland (D); CMA = North Central; Bioregion = Victorian Riverina; VH CLIMATE potential. An erect annual herb 30 cm to 150 cm high. “…an aggressive coloniser of fallows, wasteland, roadsides, and overgrazed pastures” (Parsons, Cuthbertson 2001). Monoculture within a specific layer; displaces all species within a strata.

10(c) Impact on low value EVC? EVC = Loamy Sandy Mallee (LC); CMA = Mallee; Bioregion = Lowan Mallee; VH CLIMATE potential. An erect annual herb 30 cm to 150 cm high. “…an aggressive coloniser of fallows, wasteland, roadsides, and overgrazed pastures” (Parsons, Cuthbertson 2001). Major displacement of some dominant species within a strata.

11. Impact on structure? “Most seeds germinate at the one time, producing a mat of seedlings. The young rosettes, with their leaves closely appressed to the soil prevent the emergence of other species leading to pure stands of parthenium weed” (Parsons, Cuthbertson 2001) – major effect on all layers. Forms monoculture; no other layers present.

12. Effect on threatened flora? “Most seeds germinate at the one time, producing a mat of seedlings. The young rosettes, with their leaves closely appressed to the soil prevent the emergence of other species leading to pure stands of parthenium weed” (Parsons, Cuthbertson 2001). In experiments using crop plants typical of the region, pollen was dusted onto the flowers of tomato, brinjal, chilli pepper and bean; pollen leachates were also tested in vitro against pollen from the crop plants. The results clearly demonstrated an inhibitory effect both on fruit set in the field and pollen germination in the laboratory. (Evans, 1997). This species is not documented as posing an additional risk to threatened flora.

FAUNA

13. Effect on threatened fauna? However, in artificial feeding tests buffalo bull calves accepted the weed, alone or in mixtures with green fodder, with severe consequences. The majority (11 out of 16) developed severe dermatitis and toxic symptoms, and died within 8-30 days.(Evans 1997). “Regular contact with the plant, usually over a prolonged period, produces an acute form of dermatitis, and asthma in humans” (Parsons, Cuthbertson 2001). This species is not documented as posing an additional risk to threatened fauna.

14. Effect on non-threatened fauna? However, in artificial feeding tests buffalo bull calves accepted the weed, alone or in mixtures with green fodder, with severe consequences. The majority (11 out of 16) developed severe dermatitis and toxic symptoms, and died within 8-30 days.(Evans 1997). Forms “pure stands of parthenium weed” (Parsons, Cuthbertson 2001) – habitat changed dramatically, could lead to possible extinction of non-threatened fauna.

15. Benefits fauna? “Livestock do not normally eat the weed” (Parsons, Cuthbertson 2001) – not likely to be an alternative food source – provides very little support to desirable species.

16. Injurious to fauna? However, in artificial feeding tests buffalo bull calves accepted the weed, alone or in mixtures with green fodder, with severe consequences. The majority (11 out of 16) developed severe dermatitis and toxic symptoms, and died within 8-30 days.(Evans 1997). Causes contact dermatitis and asthma in humans. “Cattle may also be affected, and more importantly, pass the toxic principle into their milk.” (Parsons, Cuthbertson 2001) – likely to be toxic to indigenous fauna.

PEST ANIMAL

17. Food source to pests? “Livestock do not normally eat the weed” (Parsons, Cuthbertson 2001) – not likely to provide food source.

18. Provides harbor? Grows to 150cm, forms pure stands and is an annual (Parsons, Cuthbertson 2001) – capacity to provide harbour for rabbits or foxes for parts of the year.

AGRICULTURE

19. Impact yield? In experiments using crop plants typical of the region, pollen was dusted onto the flowers of tomato, brinjal, chilli pepper and bean; pollen leachates were also tested in vitro against pollen from the crop plants. The results clearly demonstrated an inhibitory effect both on fruit set in the field and pollen germination in the laboratory. (Evans 1997). “The weed is a menace to agriculture because it competes with pastures and reduces carrying capacity” (Trounce, 1998). “Some grain sorghum crops are infested with sufficient parthenium weed plants to suppress yield”(Parsons, Cuthbertson 2001) – serious impacts on quantity. Possibly unviable to harvest crop.

20. Impact quality? Can contaminate the grain sample of sorghum crops and meat from animals who graze the plant is badly tainted, “and unfit for the table unless the animals are grazed on parthenium-free paddocks for at least a month prior to slaughter” (Parsons, Cuthbertson 2001). Consumption may also result in tainted milk (Trounce 1998) – major impact on quality. Produce likely to be rejected for sale or export.

21. Affect land values? “If allowed to spread, the weed will become a serious and persistent problem in NSW, resulting in a downgrading of property values” Trounce (1998) – major significance >10%.

22. Change land use? “Parthenium weed will become dominant if pastures are overgrazed and not managed properly. Carrying capacity will be reduced and the area will cease to be economically viable” (Trounce 1998) – major detrimental change and significant loss for agricultural usage.

23. Increase harvest costs? The presence of parthenium in cropped lands can almost double cultivation costs and restrict the sale and movement of contaminated produce. (Chippendale JF and Panetta FD 1994). Downgrading of the priority land use, to one with less agricurtural return.

24. Disease host/vector? Another indirect effect of the presence of parthenium weed is its potential role as an alternate host for crop pests.…. The notorious bacterial wilt pathogen, Pseudomonas solanacearum, has also been recorded on Parthenium hysterophorus in India (Kishun & Chand, 1988), whilst a number of crop viruses have similarly been detected, including four transmitted by Bemisia tabaci (Gennadius) (Aleyrodidae) in the southern Indian state of Tamil Nadu (Jeyarajan et al., 1988) and one (tomato leaf curl virus) in the neighbouring state of Karnataka (Sastry, 1984). Earlier work in Cuba had reported that P. hysterophorus is also a natural host and reservoir of potato virus X and Y. (Evans 1997). Host to major and severe disease or pest of important agricultural produce.

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Assessment ratings originally made by the Victorian Department of Primary Industries.

The entry of this assessment was made possible through the generous support of The Weed's Network.

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referenced by (1)

wra1029: Common Name - P (via parthenium weed)

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Date: 25 November 2009; 2:39:32 PM AEDT

Author Name: Niharika Anand
Author ID: anandn