Bidens pilosa L.

Title: Bidens pilosa L.

Scientific Name:

Bidens pilosa L.

Common Names:

cobbler’s pegs

Source & more images

Status:

Habitat:

Native to tropical America (GCW 2001). A weed in most regions including Europe, Africa, Americas, Asia Pacific, Australia & NZ (Weber 2003) A major crop weed (Holm et al 1977). Annual rainfall range is 500-3500mm, prefers moist sites but grows on sand, limerock & dry, infertile soils (Swarbrick 1997; Labrada 2001) & at high altitude (Becker et al 1998). Invades grassland, heathland, forest, streamlines, roadsides, forest clearings, wetlands, plantations, pasture, coastal & disturbed areas (Weber 2003;Swarbrick 1997; Mitich 1994). Found in all Australian mainland states (Richardson 2006). In NSW found on the coast, slopes & plains & has invaded remnant ‘grassy vegetation’ (SSC 2003; ESC 2002). In WA occurs in wetlands, drainage lines & lateritic screes (Florabase 1997; Hussey et al 1977).

Distribution:

Present Distribution - Australia (source: ALA)

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Optimum temperature for germination is between 20 and 35o C. Day-time temperatures below 15oC and above 45oC are unfavourable for germination (Reddy & Singh 1992). Requires natural seasonal disturbances for germination, e.g. Spring/Summer temperatures.

2. Establishment requirements? In one study, shading by the leaf canopy was shown to be effective in inhibiting germination of B. pilosa, (Fenner 1980) and in another study, no seedlings survived in a shade environment typical of that found in a rainforest understorey (Pattison, Golstein & Ares 1998). Can grow in partial shade (ESC 2002) but unable to establish under a moderate canopy. Requires access to light to establish (Holm et al 1977).

3. How much disturbance is required? Documented as invading grassland, heathland and forest (Weber 2003) as well as ‘remnant grassy vegetation’ in NSW (ESC 2002). Disturbance need only be minimal for B. pilosa to invade (SSC 2003). Establishes in only minor disturbed natural ecosystems, eg. grasslands.

GROWTH / COMPETITIVE

4. Life form? Erect annual or short-lived perennial shrubby herb to 150 cm in height (Smith 1985; Holm et al 1977). Lifeform: Other

5. Allelopathic properties? Several studies have shown Bidens pilosa to have strong allelopathic influences. Leaf or root extracts significantly suppressed germination and seedling growth of a number of crops, including, soya beans, mung beans, rice, maize radish, cucumber, lettuce, sorghum and ground nuts (Bhatt, Tomar & Misra 2001; Zeng & Luo 1995; Stevens & Tang 1985; Singh & Hazarika 1996). It was also suggested that the allelopathic compounds remain active in the dried parts of the weed and are released during decomposition (Singh & Hazarika 1996). Allelopathic properties seriously affecting some plants.

6. Tolerates herb pressure? In one study, regular manual ‘topping’ of B. pilosa plants increased the shoot and leaf yield of plants, with more regular 2 weekly harvesting producing greater yields. Plants harvested 9 times, at 3 weekly intervals, demonstrated development of flower buds (Norman 1994). Plants are likely to exhibit a similar response to herbivory. Species recovers quickly, and capable of flowering under moderate herbivory pressure.

7. Normal growth rate? This species will out-compete native species on exposed margins and in revegetation sites (SSC 2003). Found to grow three times faster than a species of similar life-form, Bidens sandwicensis (Pattison, Golstein & Ares 1998). Moderately rapid growth that is likely to equal competitive species of the same life form or exceed some other species of the same life form.

8. Stress tolerance to frost, drought, w/logg, sal. etc? Tolerates arid conditions (GCW 2001), dry infertile soils and is often most prolific on warm north facing rocky slopes (ESC 2002). It will survive all but the most extreme droughts (Labrada 2001). Above ground parts are killed by heavy frosts but plants will grow back quickly from roots. It can withstand temperatures down to –15oC (Labrada 2001) and known to grow at an altitude of 3600 m in Peru (Becker et al 1998). Occurs in wetlands (Calflora 2007) and wet dune slacks (Moreno-Casasola P & Vazquez G 1999). It is not fire tolerant but quickly invades burnt areas (Smith 1985). Evidence suggests it is moderately tolerant of drought, water logging and frost but is susceptible to fire. The level of tolerance is not clear from the information available so a medium rating has been assigned.

REPRODUCTION

9. Reproductive system? Sexual (self and cross pollination) (Grombone-Guaratini, Solferini & Semir 2004).

10. Number of propagules produced? A single plant may produce 3000-6000 seeds per year (Weber 2003). Produces above 2000 propagules.

11. Propagule longevity? Seeds were found to survive for 3-4 years in the soil seedbank (Voll et al 2001). Seeds survive less than 5 years

12. Reproductive period? Forms dense stands that cover large areas eliminating native vegetation (Weber 2003). Evidence suggests that species forms self-sustaining monocultures.

13. Time to reproductive maturity? In Argentina, the majority of a population was found to start flowering 4 months after germination (Gurvich et al 2004). Reaches maturity and produces viable propagules in under a year.

DISPERSAL

14. Number of mechanisms? Seeds are widely dispersed by adhering easily to clothes and animal fur (Weber 2003) and are also spread by wind, water and soil (SSC 2003; ESC 2002).

15. How far do they disperse? ‘The aggravating little needles will embed themselves in your clothing by the dozens every time you brush past the stems’ (Floridata 2007)’. Seeds are widely dispersed by adhering easily to clothes and animal fur (Weber 2003). Due to the ease of seed attachment to clothing and fur, it is very likely that at least one propagule will disperse greater than one kilometre.

Impact Assessment

RECREATION

1. Restrict human access? Forms dense cover along roads and trails (Smith 1985). ‘The aggravating little needles will embed themselves in your clothing by the dozens every time you brush past the stems’ (Floridata 2007). Due to the described nuisance value of the burrs (ESC 2002; Floridata 2007), its presence along trails and its growing height to 150cm (Holm et al 1977), it is likely this species could impede individual access in to certain areas.

2. Reduce tourism? Its ability to form dense cover along roads and trails (Smith 1985), height to 150cm (Holm et al 1977) and the described nuisance value of its burrs (ESC 2002; Floridata 2007), may deter some people from utilising certain recreation areas. Minor effects to recreational uses.

3. Injurious to people? The roots, leaves and flowers are strongly phototoxic. Substances isolated from the leaves can kill human skin in the presence of sunlight at concentrations as low as 10ppm (PFAF 2007). This plant is sometimes used as a food source in southern Africa (Holm et al 1977) and the leaves can be used to make a tea (PFAF 2007). It is unlikely to be used locally as a food source, however there are some potentially injurious properties present. A medium rating has been assigned.

4. Damage to cultural sites? Grows in cracks in pavements and walls (Labrada 2001). May have a moderate negative visual affect on some cultural sites or infrastructure.

ABIOTIC

5. Impact flow? Predominantly a terrestrial species, not likely to have an impact on water flow.

6. Impact water quality? Predominantly a terrestrial species, not likely to have an impact on water quality.

7. Increase soil erosion? The extensive fibrous root system (SSC 2003) and strong taproot (Labrada 2001) of this species may give it the potential to decrease the probability of soil erosion.

8. Reduce biomass? Its ability to form dense stands that cover large areas, (Weber 2003) and attain a height of 1.5m, (Holm et al 1977) could lead to a biomass increase in more open communities.

9. Change fire regime? It is not fire tolerant but quickly invades burnt areas (Smith 1985), however, no information was found documented on the capacity of B. pilosa to alter the fire regime.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC= Creekline Grassy Woodland (BCS= E); CMA= Wimmera; Bioreg= Goldfields; CLIMATE potential=VH. Can form dense stands that cover large areas eliminating native vegetation and preventing the regeneration of native species (Weber 2003; Smith 1985; Labrada 2001). Likely to cause major displacement of some dominant species within the lower vegetative strata.

10(b) Impact on medium value EVC? EVC= Hills Herb-rich woodland (BCS= D); CMA= North Central; Bioreg= Goldfields; CLIMATE potential=VH. Can form dense stands that cover large areas eliminating native vegetation and preventing the regeneration of native species (Weber 2003; Smith 1985; Labrada 2001). Likely to cause major displacement of some dominant species within the lower vegetative strata.

10(c) Impact on low value EVC? EVC= Shrubby Riverine woodland (BCS= LC); CMA= Mallee; Bioreg= Murray Mallee; CLIMATE potential=VH. Can form dense stands that cover large areas eliminating native vegetation and preventing the regeneration of native species (Weber 2003; Smith 1985; Labrada 2001). Likely to cause major displacement of some dominant species within the lower vegetative strata.

11. Impact on structure? Can form dense stands that cover large areas eliminating native vegetation and preventing the regeneration of native species (Weber 2003; Smith 1985; Labrada 2001). Potential to have major effect (<60%) on the lower vegetative strata.

12. Effect on threatened flora? Its impact specifically on threatened flora was not found documented but its capacity to form dense stands eliminating and inhibiting the establishment of native vegetation (Weber 2003; Smith 1985) is likely to similarly affect threatened species.

FAUNA

13. Effect on threatened fauna? Its capacity to eliminate native vegetation and prevent its establishment (Weber 2003; Smith 1985) is likely to reduce faunal habitat, however, no specific information was found documented.

14. Effect on non-threatened fauna? Its capacity to eliminate native vegetation and prevent its establishment (Weber 2003; Smith 1985) is likely to reduce faunal habitat, however, no specific information was found documented.

15. Benefits fauna? A study in NSW, found that seeds of Bidens pilosa made up approximately 50% of the Winter-Spring diet of Red-browed finches (Todd 1996). Provides an important alternative food source.

16. Injurious to fauna? Burrs are described as being a nuisance on sheep and other fleece producing livestock (ESC 2002), however, no information was found documented to suggest the species is injurious to fauna.

PEST ANIMAL

17. Food source to pests? In India, bees were found to forage throughout the year on flowers of Bidens pilosa (Reddy & Jacob 2001). In Malawi it is a plant commonly cut to feed rabbits and yields the highest gross energy content of the 16 plants tested (Ayoade, Makhambera & Kayange 1985). Known to be palatable and fed as forage to rabbits, however the extent to which it would be eaten under natural browsing conditions is unknown. Provides food for a minor pest species and may provide food for a serious pest species.

18. Provides harbor? Its ability to form dense stands (Weber 2003) and attain a height of 1.5m (Holm et al 1977) gives this species the physical capacity to harbour small to medium pest animals. However no specific information was found documented on its observed capacity to harbour pest animal species.

AGRICULTURE

19. Impact yield? In a study in Uganda, B. pilosa reduced dry bean, Phaseolus vulgaris, cropping yield by a mean of 48% (Ugen, Wien & Wortmann 2002) and in Peru, yield was reduced by 18.75- 48.9 % (Cerna & Valdez 1987). Serious impacts on quantity, > 20% reduction

20. Impact quality? Burrs are described as being a nuisance on sheep and other fleece producing livestock (ESC 2002). It is also documented as a seed contaminant of several crop species and described as a difficult weed seed to separate from grain (Bogdan 1966), however, no specific information was found documented on the level of impact it would have on agricultural quality.

21. Affect land values? Described as a principal weed of numerous crops in many countries (Holm et al 1977). It can form dense stands (Weber 2003) and significantly reduce crop yield (Cerna & Valdez 1987;Ugen, Wien & Wortmann 2002). It has also developed resistance to some herbicides, (Christoffoleti 2001; Nyabundi & Kimemia 1998) which could result in normal control practises not being effective against this species. However, no information was found documented to indicate that the presence of this species has caused reduction in land value.

22. Change land use? Described as a major weed of numerous crops in many countries (Holm et al 1977). It can form dense stands (Weber 2003) and significantly reduce crop yield (Cerna & Valdez 1987;Ugen, Wien & Wortmann 2002). It has also developed resistance to some herbicides, (Christoffoleti 2001; Nyabundi & Kimemia 1998) which could result in normal control practises not being effective against this species. The serious impact on yield and
herbicide resistance, could lead to a change in the type of crop that is grown, or perhaps, a more major change in land use. However no specific information on the capacity to which it alters land use practises was found documented.

23. Increase harvest costs? Documented as a seed contaminant of several grain crop species and described as a difficult weed seed to separate from grain (Bogdan 1966), indicating it may increase harvest costs. However, it is unclear from the information available, the level of impact it would have on harvest costs.

24. Disease host/vector? A host of Root knot nematode (Ijani, Mabagala & Nchimbi-Msolla 2000) and Tomato spotted wilt virus (NSW Agr.1953). Also known as a host of Schlerotinia sclerotiorum (Cottony Rot) and is found naturally growing infected with this disease in fields of cauliflower, maize and soya beans (Phillips 1992). Host to pest and diseases 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 an anonymous donor.

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referenced by (1)

wra997: Common Name - C (via cobblers pegs)

Article: wra2826 (permalink)
Categories: :wra:b, :wra:inv1, :wra:invmh, :wra:inv2, :wra:invml, :wra:inv3, :wra:inv4, :wra:invl, :wra:inv5, :wra:inv6, :wra:inv7, :wra:inv8, :wra:invm, :wra:inv9, :wra:inv10, :wra:invh, :wra:inv11, :wra:inv12, :wra:inv13, :wra:inv14, :wra:inv15, :wra:imp1, :wra:impml, :wra:imp2, :wra:impm, :wra:imp3, :wra:imp4, :wra:imp5, :wra:impl, :wra:imp6, :wra:imp7, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:impmh, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imph, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 26 October 2009; 3:52:29 PM AEDT

Author Name: Fariba Moslih
Author ID: moslih