Lantana camara is a low erect or subscandent, vigorous shrub with stout recurved prickles and a strong odour of black currents; it grows to 1.2-2.4 metres (or even more); its root system is very strong, and it gives out a new flush of shoots even after repeated cuttings; Leaf ovate or ovate-oblong, acute or subacute, crenate-serrate, rugose above, scabrid on both sides; Flower small, usually orange, sometimes varying from white to red in various shades and having a yellow throat, in axillary heads, almost throughout the year; Fruit small, greenish-blue black, blackish, drupaceous, shining, with two nutlets, almost throughout the year, dispersed by birds. Seeds germinates very easily. (Sastri and Kavathekar, 1990).

It is an artificial hybrid species that has been subject to intense horticultural improvement in Europe since the sixteenth century and now exists in many different forms or varieties throughout the world. Flower colour has been the primary feature for distinguishing between different forms. In Australia, these are Red, Pink, White/Pale Pink and Orange (Parsons and Cuthbertson 1992, in Thomas and Ellison 1999). Scott (1998) has proved with RAPD analysis that there is great genetic diversity within L. camara and challenged the assertion that flower colour is the primary determining factor in describing varieties (in Thomas and Ellison 1999). Inflorescences are produced in pairs in the axils of opposite leaves. In almost all colour forms, the flower opens yellow and changes to pink, white or red depending on the variety. In the forms where this does not occur, a yellow ring is present around the opening to the corollary tube (Sinha and Sharma 1984, in Day et al. 2003). The yellow colouration is known to be a visual cue to pollinating insects, and the act of pollination may stimulate colour change (Barrows 1976, Mohan Ram and Mathur 1984a, in Day et al. 2003).

Lantana camara is a highly variable species. It has been cultivated for over 300 years and now has hundred of cultivars and hybrids. These belong mostly to the L. camara complex. Cultivars can be distinguished morphologically (variation in: flower size, shape and colour; leaf size, hairiness and colour; stem thorniness), physiologically (variation in: growth rates, toxicity to livestock) and by their chromosome number and DNA content (Pierre Binggeli, 1999).

Introduction of six bird species (including Chinese turtledove, Streptopelia chinensis, and the Indian mynah, (Acridotheres tristis) that feed on lantana berries, has been implicated in the spread of the weed throughout the Hawaiian Islands as no native bird in Hawaii has been observed to eat the fruit (Perkins and Swezey 1924 in Day et al. 2003). In Guam, it has been suggested that, as a result of the introduced brown tree-snake (Boiga irregularis) preying on native bird populations, there are fewer frugivorous birds to disperse lantana seeds (R. Muniappan UG, pers. comm., in Day et al. 2003). Consequently lantana infestations are increasing more slowly, and this may partially explain why Guam has had better success with biological control of lantana than other nearby islands (Muniappan 1988, in Day et al. 2003).

Lantana camara has several uses, mainly as a herbal medicine and in some areas as firewood and mulch (Sharma et al. 1988; Sharma and Sharma 1989, in Day et al. 2003). In some countries, it is planted as a hedge to contain or keep out livestock (Bradley 1988, Ghisalberti 2000 in Day et al. 2003). There has been much work conducted, especially in India, on the chemical constituents of lantana; extracts from the leaves exhibit antimicrobial, fungicidal, insecticidal and nematicidal activity (Chavan and Nikam 1982, Sharma and Sharma 1989, Begum et al. 2000, in Day et al. 2003). The use of lantana extracts as potential biocides has been suggested. For example, aqueous leachate at 1–3% can kill water hyacinth, a troublesome weed in many tropical countries (Saxena 2000, in Day et al. 2003). Its application as a weedicide would depend on the size of the waterbodies being treated and the cost of extraction of the leachate. Verbascoside, which possesses antimicrobial, immunosuppressive and antitumor activities, has been isolated (Mahato et al. 1994, in Day et al. 2003). Lantanoside, linaroside and camarinic acid have been isolated and are being investigated as potential nematocides (Begum et al. 2000, in Day et al. 2003). Lantana oil is sometimes used for the treatment of skin itches, as an antiseptic for wounds (Anon. 1962), and externally for leprosy and scabies (Ghisalberti 2000). Plant extracts are used in folk medicine for the treatment of cancers, chicken pox, measles, asthma, ulcers, swellings, eczema, tumors, high blood pressure, bilious fevers, catarrhal infections, tetanus, rheumatism, malaria and atoxy of abdominal viscera (Anon. 1962, Kirtikar and Basu 1981, Ghisalberti 2000, in Day et al. 2003).\r\n

The stems of lantana, if treated by the sulphate process, can be used to produce pulp for paper suitable for writing and printing (Gujral and Vasudevan 1983, in Day et al. 2003). However it is hard to harvest, so is likely to be uneconomical. The roots of lantana contain a substance that may possibly be used for rubber manufacture (Gujral and Vasudevan 1983) although the economic viability of production has not been examined. Lantana twigs and stems serve as useful fuel for cooking and heating in many developing countries (Sharma et al. 1988), although it is less important than other fuel sources such as windrows, woodlots or natural bush (Bradley 1988, in Day et al. 2003). \r\n

In many regions, lantana has become a dominant component of natural and agricultural ecosystems. The rapid removal of natural forests without replacement by structurally similar\r\nnative vegetation may be partially replaced with thickets of lantana. Consequently, the amount of available habitat for native animals may decrease. In some areas, weeds such as lantana may provide shelter and vital winter food for many native birds. A number of endangered bird species utilise lantana thickets when their natural habitat is unavailable. In Australia, the vulnerable black-breasted buttonquail, Turnix melanogaster, feeds and roosts in lantana thickets adjacent to its more favoured habitat, vine forest (Smith et al. 1998, in Day et al. 2003). While buttonquails prefer intact vine forest, lantana provides an important temporary refuge for them between forest remnants (Smith et al. 1998, in Day et al. 2003). In central Kenya, where natural riverine thickets have been almost completely cleared, the endangered Hinde’s babbler, Turdoides hindei, has become dependent on lantana thickets, and unless sufficient suitable natural habitat can be restored the survival of this species depends on the retention of lantana infestations (Njoroge et al. 1998). Apart from benefiting some bird species, lantana is a major nectar source for many species of butterflies and moths.

The diverse and broad geographic distribution of lantana is a reflection of its wide ecological tolerances. It occurs in diverse habitats and on a variety of soil types. It generally grows best in open unshaded situations such as wastelands, rainforest edges, beachfronts, and forests recovering from fire or logging. Disturbed areas such as beside roads, railway tracks and canals are also favourable for the species (Thaman 1974; Winder and Harley 1983; Thakur et al. 1992, Munir 1996, in Day et al. 2003). Lantana does not invade intact rainforests, but is found on its margins (Diatloff 1975; Humphries and Stanton 1992, in Day et al. 2003). Where wet sclerophyll forests and rainforests have been disturbed through logging, gaps are created; this allows lantana to encroach on the forests. Further logging aggravates the condition and allows the lantana to spread or become thicker (Waterhouse 1970, in Day et al. 2003).\r\n

Lantana benefits from the destructive foraging activities of introduced vertebrates such as pigs, cattle, goats, horses, sheep and deer (Thaman 1974; Denton et al. 1991; Fensham et al. 1994, in Day et al. 2003), and grows well on rich volcanic soils (Humphries and Stanton 1992, in Day et al. 2003). It can grow at altitudes from sea-level to 2000m (Matthew 1971 in Day et al. 2003). It can tolerate some shade, growing in plantations and open eucalypt forests in Australia, but it does not flower readily under these conditions (Humphries and Stanton 1992, Wells and Stirton 1988, in Day et al. 2003). In Brazil, lantana rarely grows in secondary forest and commercial plantations (Winder and Harley 1983, in Day et al. 2003). Wapshere (1970) suggested that when there is reduced herbivory by natural enemies, original habitat restrictions, such as climate and soil type, may become less significant and lantana can expand into previously marginal habitats. \r\n

Lantana grows under a wide range of climatic conditions. In Australia, the inland limit of its geographical range coincides with the 750mm isohyet in southern Queensland and the 1250mm isohyet in the north (Harley 1973, in Day et al. 2003), with infestations being restricted to creek lines in drier areas (Diatloff 1975, in Day et al. 2003). It does not appear to have an upper temperature or rainfall limit and is often found in tropical areas receiving 3000mm of rainfall per year, provided that soils are sufficiently well drained. Lantana seldom occurs where temperatures frequently fall below 5°C (Cilliers 1983, in Day et al. 2003), and in South Africa it is found in areas with a mean annual surface temperature greater than 12.5°C (Stirton 1977, in Day et al. 2003). Some varieties can withstand minor frosts, provided these are infrequent (Graaff 1986 in Day et al. 2003). Prolonged freezing temperatures kill aerial woody branches and cause defoliation.\r\n

In most of the high volcanic island groups in the Pacific, the distribution of lantana is limited by: its inability to survive under dense, intact canopies of taller native forest species; its susceptibility to frosts and low temperatures; its low tolerance to saline soils; its tendency to rot in boggy or hydromorphic soils; it having never been introduced to some islands; insufficient water, due to low rainfall and/or coralline soils with poor water-holding capacities; and high incidence of tropical hurricanes (Thaman 1974, in Day et al. 2003).

Lantana flowers in most places all year round if adequate moisture and light are available (Gujral and Vasudevan 1983, Graaff 1986, in Day et al. 2003), with flowering peaking during the wet summer months. In cooler or drier regions, flowering occurs only in the warmer or wetter months, due to frost or drought damage (Winder 1980, Swarbrick et al. 1998 in Day et al. 2003). Plants can flower as early as the second growing season. Initially, lepidopteran species were thought to be the primary pollinators of lantana (Dronamraju 1958, Schemske 1976, Kugler 1980, Hilje 1985, in Day et al. 2003). Some butterfly species visit certain lantana taxa more frequently than others due to differences in corolla length, inflorescence diameter and number of flowers per inflorescence. According to this view, different varieties of lantana may have different species of pollinators. Therefore, there may be little cross-pollination between species or varieties of lantana both in the naturalised and native ranges of the section Camara (Dronamraju 1958, Schemske 1976, in Day et al. 2003). More recently, it has been suggested that thrips play a more important role in the pollination of lantana than Lepidoptera; unlike butterflies, thrips are present all year round, and are more efficient pollinators (Mohan Ram and Mathur 1984b, Sinha and Sharma 1984, in Day et al. 2003). In India, the exclusion of butterflies did not reduce seed-set and Mathur and Mohan Ram (1986) proposed the introduction of biocontrol agents to reduce thrips populations in an attempt to decrease pollination and the quantities of seed produced by lantana. In addition to butterflies and thrips, sunbirds (India) and hummingbirds (Brazil) are believed to play a minor role in pollination (Winder 1980). There are conflicting reports over lantana’s ability to selfpollinate. Pollination results in 85% fruit-set (Hilje 1985), with each infructescence bearing about eight fruits (Barrows 1976, in Day et al. 2003). Seeds are widely dispersed, predominantly by birds, but also by kangaroos, bearded dragons, sheep, goats, cattle, foxes, jackals, monkeys and possibly rodents (Bisht and Bhatnagar 1979, Clifford and Drake 1985, Sharma et al.1988, Wells and Stirton 1988, in Day et al. 2003). In continental areas, many indigenous bird species feed on the lantana fruits, while on some of the island groups, seed dispersal has been mainly facilitated by the introduction of exotic bird species. Birds are very important in exacerbating the weed problem and should not be underrated. By feeding on exotic species such as lantana, birds may increase the density and distribution of the weed at the expense of native vegetation thereby displacing other\r\nbird species (Loyn and French 1991, in Day et al. 2003). Lantana seeds need high light conditions for germination and early growth (Gentle and Duggin 1997b; Duggin and Gentle 1998, in Day et al. 2003), and seedlings are unlikely to survive beneath parent bushes. The germination rate of lantana is low under both laboratory and field conditions, with estimates of 4–20% (Graaff 1987) and 44.5% (Duggin and Gentle 1998, in Day et al. 2003). Germination rates increased from ten per cent to 46 per cent when the fleshy pulp was manually removed from the seed. This higher germination rate is comparable to that obtained from seeds collected from the faeces of wild birds. Seeds germinate at any time of the year given sufficient soil moisture, with most seed germinating after the first summer storms in northern Australia (Parsons and Cuthbertson 2001, in Day et al. 2003).

Dutch explorers introduced the plant into the Netherlands in the late 1960s from Brazil (Ghisalberti 2000) and it was then grown in glasshouses in Europe before its importation to other countries as an ornamental (Day et al. 2003).

Lantana is now a major weed in many regions of the Palaeotropics where it invades natural and agricultural ecosystems (Thomas and Ellison 1999). The plants can grow individually in clumps or as dense thickets, crowding out more desirable species. In disturbed native forests it can become the dominant understorey species, disrupting succession and decreasing biodiversity. As the density of lantana in forest increases species richness decreases (Fensham et al. 1994, in Day et al. 2003). Its allelopathic qualities can reduce vigour of plant species nearby and reduced productivity in orchards (Holm et al. 1991, in Day et al. 2003). At some sites, lantana infestations have\r\nbeen so persistent that they have completely stalled the regeneration of rainforest for three decades (Lamb 1991, in Day et al. 2003). Such is its impact that, for example, in south-east Queensland lantana was ranked as the most significant weed of non-agricultural areas (Batianoff and Butler 2002, in Day et al. 2003). Lantana competition may have caused the extinction of the shrub Linum cratericola Eliasson (Linaceae), and is a major threat to other endangered plants in the Galapagos Archipelago (Mauchamp et al. 1998, in Day et al. 2003). The replacement of native pastures by lantana is threatening the habitat of the sable antelope in Kenya (Greathead 1971b, in Day et al. 2003).

Lantana can greatly alter fire regimes in natural systems (Humphries and Stanton 1992, in Day et al. 2003). A research team from The School for Field Studies (SFS) Center for Rainforest Studies in North Queensland, Australia’s Wet Tropics, found that L. camara increases fire risk in dry rainforest by altering fuel loads. Through a suite of field and laboratory research methods, the authors concluded that L. camara is less ignitable than native rainforest species but creates a more continuous layer of ‘ladder’ fuels, which may allow fire to reach the forest canopy. They suggest that management of this species in fire susceptible ecosystems should include targeted physical removal to reduce fuel loads. (Berry et al 2011).\r\n

It can affect agriculture in a number of ways. In plantations in south-east Asia and the Pacific Island communities it can reduce productivity and interfere with harvesting. It may affect economic viability of crops such as coffee, oil palm, coconuts and cotton (Holm et al. 1977, in Thomas and Ellison 1999). In Queensland, loss of pasture is the greatest single cost of lantana invasion in grazing areas (A$3m per year at 1985 values) (Culvenor 1985, in Day et al. 2003). In dense stands of lantana, the capacity of the soil to absorb rain is lower than under good grass cover (Cilliers 1983, in Day et al. 2003). This could potentially increase the amount of run-off and the subsequent risk of soil erosion in areas infested with lantana. Lantana has been implicated in the poisoning of a number of animals including cattle, buffalo, sheep and goats (Sharma et al. 1988, in Day et al. 2003) (its leaves and seeds contain triterpenoids, which cause poisoning and photosensitivity). Poisoning mainly occurs in newly introduced young animals without access to other fodder (Everist 1974, Yadava and Verma 1978; Sharma 1994, in Day et al. 2003).\r\n

Lantana has many secondary impacts, especially in many tropical countries where it can harbour several serious pests. Malarial mosquitoes in India (Gujral and Vasudevan 1983 in Day et al. 2003) and tsetse flies in Rwanda, Tanzania, Uganda and Kenya shelter in bushes and are the cause of serious health problems (Greathead 1968, Katabazi 1983, Okoth and Kapaata 1987, Mbulamberi 1990 in Day et al. 2003).

The key to good management of lantana is constant vigilance (Day et al. 2003). Repeated control of regrowth is critical to success. Control of new infestations should be a priority because the species is able to expand its range during good seasons.

Mechanical: Mechanical clearing and hand pulling are suitable for small areas and fire can be used over large areas.

Biological: Biocontrol agents have decreased the volume of individual plants making other control methods considerably easier. None of the over 40 agents trialled have resulted in total control but some have been partially successful including Teleonemia scrupulosa Stål (Hemiptera), Octotoma scabripennis (Coleoptera), Uroplata girardi Pic (Coleoptera) and Ophiomyia lantanae (Froggatt) (Diptera) (Day et al. 2003). \r\n

L. camara was the first weed ever targeted for classical biological control at the turn of the century, and since then 36 insect species have been released in 33 countries throughout the exotic range. Despite these efforts, control of the weed has generally been disappointing (Thomas and Ellison 2000). Many reasons have been suggested for this failure: the great genetic diversity of the plant, its ability to hybridise, and that fact that its origin as a hybrid ornamental plant complicates the search for its centre of origin and thus for potential agents (Thomas and Ellison 1999; Day et al. 2003). Twenty nine biotypes exist in Australia alone (Smith and Smith 1982, in Thomas and Ellison 1999). No insect agent released to date has caused significant damage to the very important Common Pink biotype homas and Ellison 1999). In general, the insect agents released have a restricted host range within this complex, and, in addition, the weed is able to tolerate wider climatic and geographical areas (Thomas and Ellison 1999). Searches have been made in Mexico, Central America, the West Indies, and Brazil, and insects have been collected from several different lantana species. These insects have been host-tested and released in Hawaii, South Africa, Australia, several countries in east Africa, south and east Asia, and the Pacific (Day . 2003).\r\n

Fungi have been used for many years to control arthropod pests but have been underexploited against invasive weeds. Evans (1987) considered fungal pathogens to have great potential as agents for classical biological control of weeds. Barreto et al. (1995) examined the mycobiota of L. camara in Brazil and selected several fungal pathogens as potential biological control agents including Prospodium tuberculatum, Puccinia lantanae and Ceratobasidium lantanae-camarae. P. tuberculatum is a rust limited to the tropical and subtropical regions of North and South America. Glasshouse inoculations indicate that the agent is pathogenic to two major weed biotypes in Australia: the Common Pink (a highly invasive biotype) and Pink-edged Red (extremely toxic to cattle). P. lantanae is a rust of tropical origin and initial results show that it is pathogenic to a wider range of weedy cultivars of lantana than P. tuberculatum. Successful infection has been obtained with ten biotypes to date: two from Australia, three from South Africa, two from Madagascar and one from Thailand, India and Hawaii (Thomas and Ellison 1999).

A strain of the rust Prospodium tuberculatum from Brazil was screened as a potential biocontrol agent against 40 Australian Lantana camara forms and 52 closely related, non-target plant species. Results under glasshouse conditions showed that the Brazilian rust strain is pathogenic to only two flower colour forms: pink and pink-edged red. Macro- and microsymptoms were recorded using 11 assessment categories and four susceptibility ratings. No macrosymptoms were observed on any of the non-target plants (Thomas et al. 2006).