Orobanche minor Sm.

Title: Orobanche minor Sm.

Scientific Name:

Orobanche minor Sm.

Common Name:

lesser broomrape, hellroot

Source & more images (via ALA)

Habitat: As a parasite Orobanche minor occurs in association with its hosts, the most common host being Trifolium sp. however the species is reported to attack more than 50 species (Hipkin 1992; Webb, Sykes & Garnock-Jones, 1988). The species is largely reported in areas of cropping and pasture however it has also been reported to invade dry coastal vegetation, cliff faces, mixed grassland, scrubland and roadsides (ter Borg et al 1994; Carr, Yugovic & Robinson, 1992; Webb, Sykes & Garnock-Jones, 1988)

Distribution:

Original source via CABI

Invasiveness Assessment

ESTABLISHMENT

1. Germination requirements? Germination will occur after the seeds have been exposed to a period of preconditioning; have been stimulated by root exudates of host or false host species and exposed to seasonal temperature and moisture levels (Končalocá & Kropáč 1997).

2. Establishment requirements? Needs to be in the vicinity of the roots of a host plant (Evans 1962).

3. How much disturbance is required? Establishes in growing crops including clover, tobacco and broad bean (Foy et al. 1989).

GROWTH / COMPETITIVE

4. Life form? Other; an annual or perennial herbaceous obligate root parasite (Holm et al. 1997).

5. Allelopathic properties? Does reduce the host plants vigour, however there is allelopathy reported.

6. Tolerates herb pressure? In Europe it is considered unpalatable by stock as it smells and has a bitter taste, however it has been reported to be grazed in Australia (Evans 1962). Grazing by sheep has reportedly resulted in death of those plants grazed, can be eliminated with heavy grazing (Southwood 1971). Grazing may kill plants but seeds of other Orobanche sp. have been reported to remain viable after passing through a sheep (Foy et al. 1989). Therefore under moderate grazing the species is considered to be still capable of sexual reproduction.

7. Normal growth rate? As a parasite Orobanche clearly has a competitive advantage over any of its host species, it can effectively stop the host plant growing (Eizenberg, Colquhoun & Mallory-Smith 2005). Once the plant emerges it will flower set seed and die back in the space of a few months (Holm et al. 1997). Therefore the species is considered to be competitive with other fast growing annual and perennial herbs.

8. Stress tolerance to frost, drought, w/logg, sal. etc? Unknown, probably dependent on host species.

REPRODUCTION

9. Reproductive system? Produces seed through self pollination (Elias et al. 2006).

10. Number of propagules produced? Jones (1991) report a maximum theoretical seed production of 111,780 seeds, if the plant produced 90 flowers which was the maximum number produced by a plant during their study and each capsule contained 1242 seeds which was also the maximum found during their study. The seed production is deemed high as to produce more than 200 seeds, either the plant with 90 flowers only need to produce 25 seeds per capsule or two capsules with the maximum number of seeds of 1242.

11. Propagule longevity? There are reports that the species seeds can remain viable for more than 10 years, it is unknown however what proportion remain viable. Seeds can remain viable in the soil for more than 10 years (Elias et al. 2006). Seed remains viable in the soil for 10-15 years (Edwards 1972).

12. Reproductive period? Under favourable conditions can have two periods of reproduction, however most commonly acts as an annual (Evans 1962).

13. Time to reproductive maturity? The species is treated as an annual however the seedlings may live in the soil for a number of years before emerging (Mussleman 1994).

DISPERSAL

14. Number of mechanisms? Seeds are very small and can be dispersed by wind, water, grazing animals and accidental human dispersal though contamination (Elias et al. 2006).

15. How far do they disperse? Not specifically known; however with the range and number of dispersal agents it is likely that some seeds will disperse more than 1km.

Impact Assessment

RECREATION

1. Restrict human access? Small plant growing in association with another species, unlikely to restrict access.

2. Reduce tourism? Reported to produce a foul smell in Europe, but not in Australia (Evans 1962). If it did produce the smell it may have some impact on aesthetics.

3. Injurious to people? No evidence of this reported.

4. Damage to cultural sites? Reported to produce a foul smell in Europe, but not in Australia (Evans 1962). If it did produce the smell it may have some impact on aesthetics. Reported attack garden plants including roses (Evans 1962). This may have some impact on the aesthetics of heritage sites that include landscaped gardens.

ABIOTIC

5. Impact flow? Terrestrial species, therefore unlikely to impact on water flow.

6. Impact water quality? Terrestrial species, therefore unlikely to impact on water quality.

7. Increase soil erosion? Unknown, Weakens the host plant, and with no significant root system of its own, may leave the soil more open to erosion.

8. Reduce biomass? Parasite therefore any biomass it accumulates would have been accumulated by the host plant (Eizenberg, Colquhoun & Mallory-Smith 2005).

9. Change fire regime? Unknown.

COMMUNITY HABITAT

10(a) Impact on composition of high value EVC? EVC= Coastal Tussock Grassland (V); CMA= Corangamite; Bioreg= Otway Plain; VH CLIMATE potential. Reported largely as a weed of agriculture, however being a parasite it won’t necessarily displace any species, but weaken the host while it is flowering (ter Borg et al 1994).

10(b) Impact on medium value EVC? EVC= Coastal Tussock Grassland (D); CMA= West Gippsland; Bioreg= Wilsons Promontory; VH CLIMATE potential. Reported largely as a weed of agriculture, however being a parasite it won’t necessarily displace any species, but weaken the host while it is flowering (ter Borg et al 1994).

10(c) Impact on low value EVC? EVC= Coastal Tussock Grassland (LC); CMA= Port Phillip; Bioreg= Gippsland Plain; VH CLIMATE potential. Reported largely as a weed of agriculture, however being a parasite it won’t necessarily displace any species, but weaken the host while it is flowering (ter Borg et al 1994).

11. Impact on structure? Reported largely as a weed of agriculture, however being a parasite it won’t necessarily displace any species, but weaken the host while it is flowering (ter Borg et al 1994).

12. Effect on threatened flora? Unknown, however as it mainly effect agricultural crops it is unlikely to have any significant impact.

FAUNA

13. Effect on threatened fauna? Unknown, however as it mainly effect agricultural crops it is unlikely to have any significant impact.

14. Effect on non-threatened fauna? The weakening of host species may have some minor impact on some food supplies (ter Borg et al 1994).

15. Benefits fauna? It has been reported to be grazed by stock in Australia (Evans 1962). However in relation to the fodder the host plant could have accumulated this is minor (Eizenberg, Colquhoun & Mallory-Smith 2005).

16. Injurious to fauna? No evidence of this reported

PEST ANIMAL

17. Food source to pests? It has been reported to be grazed by stock in Australia (Evans 1962). However in relation to the fodder the host plant could have accumulated this is minor (Eizenberg, Colquhoun & Mallory-Smith 2005).

18. Provides harbor? Small plant which only emerges above ground for a few months a year (Holm et al 1997). Unlikely to provide anything in the way of shelter.

AGRICULTURE

19. Impact yield? Not as significant as other broomrapes it does however infest a number of crops and cause some damage (Foy et al 1989). It is not reported to what extent O. minor reduces the quantity of the crop. Yield of clover has been shown to decrease however this has little impact on the overall pasture production (Evans 1962).

20. Impact quality? One flower spike has caused an entire crop of red clover grown for seed production, to be declared unfit in the
Netherlands and others to be harvested for forage instead of seed (ter Borg et al 1994).

21. Affect land values? Unknown

22. Change land use? Changing to a crop that is not affected by broomrape or a false host either permanently or in rotation to minimise the seed bank may occur (Lins, Colquhoun & Mallory-Smith 2006).

23. Increase harvest costs? As a parasite this species could be considered a disease (Holm et al 1997).

24. Disease host/vector?

Feedback

Do you have additional information about this plant that will improve the quality of the assessment? If so, we would value your contribution.

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.

Attachments:

1151358.jpg
broomrape via ala.JPG
distribution_map (31).png

referenced by (2)

wra1008: Common Names - L (via lesser broomrape)wra1002: Common Name - H (via hellroot)

Article: wra3397 (permalink)
Categories: :wra:o, :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:impl, :wra:imp2, :wra:imp3, :wra:imp4, :wra:impml, :wra:imp5, :wra:imp6, :wra:imp7, :wra:impm, :wra:imp8, :wra:imp9, :wra:imp10a, :wra:imp10b, :wra:imp10c, :wra:imp11, :wra:imp12, :wra:imp13, :wra:imp14, :wra:imp15, :wra:imph, :wra:imp16, :wra:imp17, :wra:imp18, :wra:imp19, :wra:imp20, :wra:imp21, :wra:imp22, :wra:imp23, :wra:imp24
Date: 29 October 2009; 10:23:15 AM AEDT

Author Name: David Low
Author ID: adminDavid