Lantana

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This Weed Risk Management Assessment uses a series of questions to arrive at scores for weed risk and feasibility of coordinated control for this weed, and displays the necessary management actions derived from these scores.

This information is then used to make decisions about the introduction, prioritisation and declaration of this weed in New South Wales.

Weed Risk
Weed (Scientific name)	Lantana camara, L. montevidensis (including species in the genera)
Weed (Common name)	Lantana
Region	All of NSW
Management area	Grazing land (includes modified pastures in eastern NSW and rangeland in western NSW)
Landuse	3.2 Grazing modified
Assumptions	Lantana species Verbenaceae Standard weed management is limited. In the east pasture management for competitive pastures and varying stocking rates are most common. Fertiliser application is common in the east in some places. Herbicide application may be used as well as cultivation and re-sowing of areas. Limited use of broad-scale herbicide applications and cultivation in the west. Density in land use - low.
Invasiveness	Score Total	Answers	Source and comments
Q1. What is the ability of the weed to establish amongst existing plants?	1.0	Seedlings establish after moderate disturbance	Johnson (2008), pg. 25-26 (some evidence suggests L. montevidensis can establish amongst average infestations of weeds better).
Q2. What is the weed's tolerance to average weed management practices in the land use?	3.0	95% + weeds survive common management	Johnson (2008), pg. 25-26 and personal observations.
Q3. What is the reproductive ability of the weed in the land use?	2.0		Johnson (2008), pg. 17-20.
(a) Time to seeding	1.0	>1-3 yrs
(b) Annual seed production	2.0	High
(c) Vegetative reproduction	1.0	Infrequent
Q4. How likely is long-distance dispersal (>100m) by natural means?	2.0		Johnson (2008), pg. 19-20. Wind not mentioned.
(a) Flying animals	2.0	Common
(b) Other wild animals	2.0	Common
(c) Water	1.0	Occasional
(d) Wind	0.0	Unlikely
Q5. How likely is long-distance dispersal (>100 m) by human means?	2.0		Johnson (2008), pg. 19-20. Sale of L. camara and L. montevidensis ceased but hybrid marketing still probably occurs to a limited extent (despite sale ban).
(a) Deliberate spread by people	1.0	Occasional
(b) Accidentally by people and vehicles	1.0	Occasional
(c) Contaminated produce	0.0	Unlikely
(d) Domestic/farm animals	1.0	Occasional
Total	6.7
Impacts	Score Total
Q1. Does the weed reduce the establishment of desired plants?	1.0	< 10% reduction	Known low reduction for L. camara - Johnson (2008) pg. 25 (though overall more research is needed).
Q2. Does the weed reduce the yield or amount of desired vegetation?	1.0	< 10% reduction	Known low reduction for L. camara - Johnson (2008) pg. 25 (may be higher for L. montevidensis).
Q3. Does the weed reduce the quality of products, diversity or services available from the land use?	3.0	High	Johnson (2008), pg. 25. Coutts-Smith and Downey (2006).
Q4. What is the weed's potential to restrict the physical movement of people, animals, vehicles, machinery and/or water?	2.0	Medium	Higher for L. camara than L. montevidensis - personal observations.
Q5. What is the weed's potential to negatively affect the health of animals and/or people?	2.0	Medium	Certain L. camara varieties but unclear for L. montevidensis (Johnson 2008), pg. 25.
Q6. Does the weed have major positive or negative effects on environmental health?	0.0		Johnson (2008), pg. 25 and 27. Scores mainly influenced by L. camara although both species have major positive influences on soil stability.
(a) food/shelter	-1.0	Major positive effect
(b) fire regime	1.0	Major negative effect
(c) altered nutrient levels	-1.0	Major positive effect
(d) soil salinity	0.0	Minor or no effect
(e) soil stability	-1.0	Major positive effect
(f) soil water table	0.0	Minor or no effect
Total	4.7
Potential distribution	Total
Q1. Within the geographic area being considered, what is the percentage area of land use that is suitable for the weed?	2.0	10-20% of land use	Estimate (based on Johnson (2008), pg. 24 and 25 - extended to the whole state). It is likely to be toward the lower end of this range.
Comparative weed risk score	63
Weed risk category	Medium
Feasibility of coordinated control
Control costs	Score Total
Q1. How detectable is the weed?	2		Johnson (2008), pg. 5, 7 and 19. Also personal observations. Scoring is more for a composite of the species.
(a) Distinguishing features	1	sometimes distinct
(b) Period of year shoot growth visible	0	> 8 months
(c) Height at maturity	2	<0.5 m
(d) Pre-reproductive height in relation to other vegetation	1	similar height
Q2. What is the general accessibility of known infestations at the optimum time of treatment?	1	medium	Personal observations - overall.
Q3. How expensive is management of the weed in the first year of targeted control?	2		Estimates based on best-practice.
(a) Chemical costs/ha	1	low (< $100/ha)
(b) Labour costs/ha	1	low (< $100/ha)
(c) Equipment costs	1	low
Q4. What is the likely level of participation from landholders/volunteers within the land use at risk?	1.0	medium	Personal observations.
Total	5.0
Persistence	Score Total
Q1. How effective are targeted management treatments applied to infestations of the weed?	2	medium	Johnson (2008), pg. 32-36 - L. montevidensis less control than L. camara.
Q2. What is the minimum time period for reproduction of sexual or vegetative propagules?	1	1-2 years	Known low reduction for L. camara - Johnson (2008) pg. 25 (though overall more research is needed). - plants do not flower in the first season.
Q3. What is the maximum longevity of sexual or vegetative propagules?	1	2-5 years	Johnson (2009), pg. 18.
Q4. How likely are new propagules to continue to arrive at control sites, or to start new infestations?	2.0		Johnson (2009), pg. 19-20.
(a) Long-distance (>100m) dispersal by natural means	2	frequent
(b) Long-distance (>100m) dispersal by human means	0	rare
Total	5.5
Current distribution	Total
Q1. What percentage area of the land use in the geographical area is currently infested by the weed?	2.0	10-20% of land use	Estimate. L. montevidensis is very restricted at this time.
Q2. What is the number of infestations, and weed distribution within the geographic area being considered?	2.0	widespread	Based on L. camara. L. montevidensis is very restricted at this time.
Total	3.3
Comparative feasibility of coordinated control score	91
Feasibility of coordinated control category	Low
Management priority category	Manage sites
Calculation of overall uncertainty score	0%
Positive impacts	Johnson (2008), pg. 29-31. Originally introduced into Australia as an ornamental, some role in erosion control. L. camara provides replacement habitat where natives cleared. Also used for essential oils and other uses.
References/Other comments
Coutts-Smith, A. J. and Downey, P. O. (2006). The impact of weeds on threatened biodiversity in NSW. Technical series no.11. CRC for Australian Weed Management Systems, Adelaide. 100 pp. Johnson, S. B. (2008). Review of the declaration of Lantana species in New South Wales. New South Wales Department of Primary Industries, Orange. 63 pp. Assessment by Dr Stephen Johnson, Weed ecologist, I&I NSW, 30 April 2010. Medium weed risk. Declaration to support threatened native species and communities. Declaration also to prevent further spread of Lantana species and hybrids.