Economic damage. Mats of S. molesta

Economic damage. Mats of S. molesta (referred to hereafter as salvinia) impede access to and use of waterways for commercial and recreational purposes and degrade waterside aesthetics (Fig. 1). Mats reduce habitats for game birds, limit access to fishing areas, and probably alter fisheries, all with negative economic consequences. Salvinia can clog water intakes and interfere with agricultural irrigation, water supply, and electrical generation. It provides habitats for vectors of human disease with serious socioeconomic impacts.
In developing countries, the impact of salvinia can be devastating because weed mats block the use of
Figure 1. Salvinia molesta D.S. Mitchell
covering a farm pond in Texas restricts
commercial and recreational use and degrades aesthetics. (Photography by T. Center.)
waterways for transportation, cutting off access to important services, farm lands, and hunting grounds. The harm from salvinia mats to fisheries also can be very significant to communities dependent on fish for local consumption (sometimes as the main source of protein) or in areas where fish sales are the main source of cash income (Bennett, 1966; Thomas and Room, 1986). Salvinia also is a weed of paddy rice that reduces production by competing for water, nutrients and space (Anon., 1987).

Ecological damage. The ability to grow very quickly (Cary and Weerts, 1983; Mitchell and Tur, 1975; Mitchell, 1978/9; Room, 1986) and blanket water bodies makes salvinia an aggressive and competitive weed (Fig. 2). Initially, salvinia forms a single layer over water, but with continued growth the mats become multi-layered and can reach up to 1 m in thickness (Thomas and Room, 1986). Thick mats support other colonizing plants, and the high biomass and stability of such mats make them difficult to dislodge and destroy (Storrs and Julien, 1996).
Plants and animals dependent on open water to gain sunlight, oxygen, and space for sustenance and growth, or for landing, fishing, nest building, or mating, are displaced
Figure 2. Salvinia molesta D.S. Mitchell
covering a waterbody and supporting the
growth of other plant species in Kakadu
National Park, Australia. (Photograph by
M. Julien.)
by dense salvinia infestations. Water under mats of salvinia has a lower oxygen concentration (due to reduced surface area of water available for oxygenation, inhibition of photosynthesis by submerged plants, and consumption of dissolved oxygen by decaying salvinia), higher carbon dioxide and hydrogen sulphide concentrations, lower pH, and higher temperatures than nearby open water (Mitchell, 1978; Thomas and Room, 1986).
Through high growth rates and slow decomposition rates, salvinia reduces the concentration of nutrients that would otherwise be available to primary producers and organisms that depend on them (Sharma and Goel, 1986; Storrs and Julien, 1996).
Mats of salvinia provide ideal habitat for Mansonia mosquitoes, a principal vector of rural elephantiasis in Sri Lanka (Pancho and Soerjani, 1978), and for other mosquito species involved in the transmission of encephalitis, dengue fever, and malaria (Creagh, 1991/92). Two species of Mansonia that occur in the United States, Mansonia dyari Belkin and Mansonia titillans (Walker), have been implicated in the transmission of St. Louis encephalitis and Venezuelan equine encephalitis, respectively (Lounibos et al., 1990).
Extent of losses. The most detailed assessment of costs caused by salvinia was conducted in Sri Lanka using 1987 as the base year (Doeleman, 1989). Paddy rice losses, fishing losses, other losses (power generation, transport, washing and bathing, etc.), health costs, abatement costs, and economic benefits were considered. No environmental costs were included, but they were recognized as important. There were no identified benefits from salvinia. Total costs associated with salvinia were estimated to be between 24.7 million and 56.7 million rupees (in Australian dollars, between 0.9 and 2.1 million) for 1987. This information was used to determine the benefits from biological control over the following 25 years. The benefits were 53 rupees or dollars per rupee or dollar invested, or 1,673 man-hours per man-hour invested.
Using this information as a guide, Room and Julien (1995) estimated that the annual benefits gained from successful biological control of salvinia worldwide were approximately $150 million U.S.
Geographical Distribution
The native range of salvinia is an area in southeastern Brazil (Forno and Harley, 1979). Its first recorded exotic establishment was in Sri Lanka in 1939 (Williams, 1956). It has since become established in India (Cook and Gut, 1971), Australia (Room and Julien, 1995), Papua New Guinea (Mitchell, 1979), Cuba, Trinidad, Guyana, Columbia (Holm et al., 1979), South Africa (Cilliers, 1991), Botswana (Edwards and Thomas, 1977), Kenya, Zambia (Mitchell and Tur, 1975), Namibia (Forno and Smith, 1999), Madagascar (Room and Julien, 1995), Ghana and Cote D’Ivoire (M. Julien, pers. obs.), Indonesia (Java, Borneo, Sulawesi), Malaysia (mainland Sabah, Sarawak) (R. Chan, pers. comm.), the Philippines (Pablico et al., 1989), Fiji (Kamath, 1979), and New Zealand (Randall, 1996).
Salvinia was first reported outside of cultivation in the United States in 1995 at a pond in southeastern South Carolina (Johnson, 1995). It was eradicated before spread occurred. It was next found in Houston, Texas, in May 1998, and then at other sites in Texas and in Louisiana during 1998. During 1999 it was found in ponds and rivers in Alabama, Arizona, California, Florida, Georgia, Hawaii, Mississippi, and Oklahoma (Jacono et al., 2000; see also Jacono’s web site). Salvinia is readily available for purchase in the United States, particularly through the Internet.
Background Information on Pest Plant
Taxonomy
The aquatic fern family Salviniaceae is placed within the order Hydropteridales and consists of a single genus, Salvinia. Ten species of Salvinia occur worldwide (Herzog, 1935; de la Sota, 1962, 1963, 1964, 1982; Mitchell, 1972). None are native to the United States (Jacono et al., 2000) although seven species
originate in the Americas (de la Sota, 1976). Salvinia molesta was given recognition as a species in 1972 (Mitchell, 1972) and is grouped within the Salvinia auriculata complex, together with Salvinia auriculata Aublet, Salvinia biloba Raddi, and Salvinia herzogii de la Sota (Mitchell and Thomas, 1972). Species within this complex are characterized by the presence of divided but apically joined "basket" hairs on the abaxial surface, which produce an "egg-beater-like" appearance (Fig. 3a) (de la Sota, 1962; Mitchell and Thomas, 1972; Forno, 1983). Salvinia molesta can be distinguished from species within the S. auriculata complex by the arrangement of sporangia, the shape of sporocarps (Mitchell and Thomas, 1972; Mitchell, 1972), and by the pattern of leaf venation (Forno, 1983).
The accepted common name is salvinia, but it also is called Kariba weed, water fern, or African pyle (in Africa); giant azolla or Australian azolla (in the Philippines); and giant salvinia, water spangles, or floating fern (in the United States).
Salvinia minima Baker, the only other Salvinia species present in the United States also is exotic and can be distinguished by the presence of divided hairs on the abaxial leaf surface that are spreading and free at the tips (Fig. 3b).
Figure 3a. Salvinia species in the
United States can be distinguished by
their leaf hairs. In Salvinia molesta the
hairs form an 'eggbeater' shape at the
tips. (Photographs by M. Julien.)


Figure 3b. In Salvinia minima the hairs
are separated at the tips. (Photographs
by T. Center.)

Biology
Plant form. Salvinia is a free-floating aquatic fern with a horizontal rhizome just beneath the water surface (Bonnet, 1955; Room, 1983). Each plant is a colony of ramets. Each ramet comprises an internode, a node, a pair of floating leaves, the submerged ‘root,’ and associated buds. The "root" is a modified leaf that looks and functions like a root (Croxdale 1978, 1979, 1981).
Salvinia is morphologically variable, primarily in response to the level of crowding and availability of nutrients. These two factors are largely independent of one another. There are three growth forms, with a continuum among them, that are associated with the degree of crowding experienced by the plant (Mitchell and Tur, 1975).
The primary form (Fig. 4a) occurs as isolated plants in the initial ‘invading’ stage of an infestation. This form has small, oval leaves less than 15 mm wide that lie flat on the water surface.
The secondary form (Fig. 4b) occurs when plants have been growing over open water for some time, either freely or on the edge of stable mats. Internodes are longer, with larger, boat-shaped (slightly keeled) leaves that have rounded apices and are variable in size, but are normally between 20 mm and 50 mm wide. The entire lower leaf surface is in contact with the water.
The tertiary form (Fig. 4c) occurs when plants are growing in crowded mat conditions associated with mature infestations. Internodes are short with large heart-shaped, or oblong and deeply keeled leaves up to 60 mm in width when fully opened. The undersides of adjacent leaves are in contact with each other.
Figure 4a. The primary form of Salvinia
molesta D.S. Mitchell. (Photographs by M. Julien.)


Figure 4b. The secondary form of Salvinia molesta D.S. Mitchell. (Photographs by M. Julien.)


Figure 4c. The tertiary form of Salvinia molesta D.S. Mitchell. (Photographs by M. Julien.)
Growth and reproduction. Salvinia is pentaploid, has a chromosome number of 45, and is incapable of sexual reproduction (Loyal and Grewal, 1966). Each node bears a series of up to three axillary buds that develop successively under normal growing conditions (Room, 1988), and up to six in response to damage (Julien and Bourne, 1986). The number of axillary buds that grow, the rat

Results (Indonesian) 1:

Kerusakan ekonomi. Tikar S. molesta (disebut kiambang) menghambat akses ke dan penggunaan saluran air untuk tujuan komersial dan rekreasi dan menurunkan tepi Sungai estetika (Fig. 1). Tikar mengurangi habitat burung permainan, membatasi akses ke daerah Perikanan, dan mungkin mengubah Perikanan, semua dengan konsekuensi ekonomi negatif. Kiambang dapat menyumbat asupan air dan mengganggu Irigasi Pertanian, pasokan air dan listrik generasi. Ini menyediakan habitat vektor penyakit manusia dengan dampak sosial ekonomi yang serius.Di negara berkembang, dampak kiambang dapat menghancurkan karena gulma tikar memblokir penggunaan Gambar 1. Kiambang molesta DS Mitchell meliputi kolam farm di Texas membatasi penggunaan komersial dan rekreasi dan estetika. (Fotografi oleh T. Pusat.)perairan transportasi, memotong akses ke layanan penting, tanah-tanah pertanian dan taman berburu. Kerugian dari tikar kiambang Perikanan juga dapat menjadi sangat penting bagi masyarakat yang bergantung pada ikan untuk konsumsi lokal (kadang-kadang sebagai sumber utama protein) atau di daerah di mana ikan penjualan sumber utama pendapatan tunai (Bennett, 1966; Thomas dan kamar, 1986). Kiambang juga gulma padi yang mengurangi produksi bersaing untuk air, nutrisi dan ruang (Anon., 1987).Ecological damage. The ability to grow very quickly (Cary and Weerts, 1983; Mitchell and Tur, 1975; Mitchell, 1978/9; Room, 1986) and blanket water bodies makes salvinia an aggressive and competitive weed (Fig. 2). Initially, salvinia forms a single layer over water, but with continued growth the mats become multi-layered and can reach up to 1 m in thickness (Thomas and Room, 1986). Thick mats support other colonizing plants, and the high biomass and stability of such mats make them difficult to dislodge and destroy (Storrs and Julien, 1996).Plants and animals dependent on open water to gain sunlight, oxygen, and space for sustenance and growth, or for landing, fishing, nest building, or mating, are displaced Figure 2. Salvinia molesta D.S. Mitchell covering a waterbody and supporting the growth of other plant species in Kakadu National Park, Australia. (Photograph by M. Julien.)by dense salvinia infestations. Water under mats of salvinia has a lower oxygen concentration (due to reduced surface area of water available for oxygenation, inhibition of photosynthesis by submerged plants, and consumption of dissolved oxygen by decaying salvinia), higher carbon dioxide and hydrogen sulphide concentrations, lower pH, and higher temperatures than nearby open water (Mitchell, 1978; Thomas and Room, 1986).Through high growth rates and slow decomposition rates, salvinia reduces the concentration of nutrients that would otherwise be available to primary producers and organisms that depend on them (Sharma and Goel, 1986; Storrs and Julien, 1996). Mats of salvinia provide ideal habitat for Mansonia mosquitoes, a principal vector of rural elephantiasis in Sri Lanka (Pancho and Soerjani, 1978), and for other mosquito species involved in the transmission of encephalitis, dengue fever, and malaria (Creagh, 1991/92). Two species of Mansonia that occur in the United States, Mansonia dyari Belkin and Mansonia titillans (Walker), have been implicated in the transmission of St. Louis encephalitis and Venezuelan equine encephalitis, respectively (Lounibos et al., 1990).Extent of losses. The most detailed assessment of costs caused by salvinia was conducted in Sri Lanka using 1987 as the base year (Doeleman, 1989). Paddy rice losses, fishing losses, other losses (power generation, transport, washing and bathing, etc.), health costs, abatement costs, and economic benefits were considered. No environmental costs were included, but they were recognized as important. There were no identified benefits from salvinia. Total costs associated with salvinia were estimated to be between 24.7 million and 56.7 million rupees (in Australian dollars, between 0.9 and 2.1 million) for 1987. This information was used to determine the benefits from biological control over the following 25 years. The benefits were 53 rupees or dollars per rupee or dollar invested, or 1,673 man-hours per man-hour invested.Using this information as a guide, Room and Julien (1995) estimated that the annual benefits gained from successful biological control of salvinia worldwide were approximately $150 million U.S.Geographical DistributionThe native range of salvinia is an area in southeastern Brazil (Forno and Harley, 1979). Its first recorded exotic establishment was in Sri Lanka in 1939 (Williams, 1956). It has since become established in India (Cook and Gut, 1971), Australia (Room and Julien, 1995), Papua New Guinea (Mitchell, 1979), Cuba, Trinidad, Guyana, Columbia (Holm et al., 1979), South Africa (Cilliers, 1991), Botswana (Edwards and Thomas, 1977), Kenya, Zambia (Mitchell and Tur, 1975), Namibia (Forno and Smith, 1999), Madagascar (Room and Julien, 1995), Ghana and Cote D’Ivoire (M. Julien, pers. obs.), Indonesia (Java, Borneo, Sulawesi), Malaysia (mainland Sabah, Sarawak) (R. Chan, pers. comm.), the Philippines (Pablico et al., 1989), Fiji (Kamath, 1979), and New Zealand (Randall, 1996).Salvinia was first reported outside of cultivation in the United States in 1995 at a pond in southeastern South Carolina (Johnson, 1995). It was eradicated before spread occurred. It was next found in Houston, Texas, in May 1998, and then at other sites in Texas and in Louisiana during 1998. During 1999 it was found in ponds and rivers in Alabama, Arizona, California, Florida, Georgia, Hawaii, Mississippi, and Oklahoma (Jacono et al., 2000; see also Jacono’s web site). Salvinia is readily available for purchase in the United States, particularly through the Internet.Background Information on Pest PlantTaxonomyThe aquatic fern family Salviniaceae is placed within the order Hydropteridales and consists of a single genus, Salvinia. Ten species of Salvinia occur worldwide (Herzog, 1935; de la Sota, 1962, 1963, 1964, 1982; Mitchell, 1972). None are native to the United States (Jacono et al., 2000) although seven species originate in the Americas (de la Sota, 1976). Salvinia molesta was given recognition as a species in 1972 (Mitchell, 1972) and is grouped within the Salvinia auriculata complex, together with Salvinia auriculata Aublet, Salvinia biloba Raddi, and Salvinia herzogii de la Sota (Mitchell and Thomas, 1972). Species within this complex are characterized by the presence of divided but apically joined "basket" hairs on the abaxial surface, which produce an "egg-beater-like" appearance (Fig. 3a) (de la Sota, 1962; Mitchell and Thomas, 1972; Forno, 1983). Salvinia molesta can be distinguished from species within the S. auriculata complex by the arrangement of sporangia, the shape of sporocarps (Mitchell and Thomas, 1972; Mitchell, 1972), and by the pattern of leaf venation (Forno, 1983).The accepted common name is salvinia, but it also is called Kariba weed, water fern, or African pyle (in Africa); giant azolla or Australian azolla (in the Philippines); and giant salvinia, water spangles, or floating fern (in the United States).Salvinia minima Baker, the only other Salvinia species present in the United States also is exotic and can be distinguished by the presence of divided hairs on the abaxial leaf surface that are spreading and free at the tips (Fig. 3b). Figure 3a. Salvinia species in the United States can be distinguished by their leaf hairs. In Salvinia molesta the hairs form an 'eggbeater' shape at the tips. (Photographs by M. Julien.) Figure 3b. In Salvinia minima the hairs are separated at the tips. (Photographs by T. Center.)BiologyPlant form. Salvinia is a free-floating aquatic fern with a horizontal rhizome just beneath the water surface (Bonnet, 1955; Room, 1983). Each plant is a colony of ramets. Each ramet comprises an internode, a node, a pair of floating leaves, the submerged ‘root,’ and associated buds. The "root" is a modified leaf that looks and functions like a root (Croxdale 1978, 1979, 1981).Salvinia is morphologically variable, primarily in response to the level of crowding and availability of nutrients. These two factors are largely independent of one another. There are three growth forms, with a continuum among them, that are associated with the degree of crowding experienced by the plant (Mitchell and Tur, 1975).The primary form (Fig. 4a) occurs as isolated plants in the initial ‘invading’ stage of an infestation. This form has small, oval leaves less than 15 mm wide that lie flat on the water surface.The secondary form (Fig. 4b) occurs when plants have been growing over open water for some time, either freely or on the edge of stable mats. Internodes are longer, with larger, boat-shaped (slightly keeled) leaves that have rounded apices and are variable in size, but are normally between 20 mm and 50 mm wide. The entire lower leaf surface is in contact with the water.The tertiary form (Fig. 4c) occurs when plants are growing in crowded mat conditions associated with mature infestations. Internodes are short with large heart-shaped, or oblong and deeply keeled leaves up to 60 mm in width when fully opened. The undersides of adjacent leaves are in contact with each other. Figure 4a. The primary form of Salvinia molesta D.S. Mitchell. (Photographs by M. Julien.) Figure 4b. The secondary form of Salvinia molesta D.S. Mitchell. (Photographs by M. Julien.) Figure 4c. The tertiary form of Salvinia molesta D.S. Mitchell. (Photographs by M. Julien.)Growth and reproduction. Salvinia is pentaploid, has a chromosome number of 45, and is incapable of sexual reproduction (Loyal and Grewal, 1966). Each node bears a series of up to three axillary buds that develop successively under normal growing conditions (Room, 1988), and up to six in response to damage (Julien and Bourne, 1986). The number of axillary buds that grow, the rat

Results (Indonesian) 2:

Kerusakan ekonomi. Mats S. molesta (selanjutnya disebut sebagai Salvinia) menghalangi akses ke dan penggunaan saluran air untuk tujuan komersial dan rekreasi dan menurunkan estetika pasisir (Gbr. 1). Mats mengurangi habitat burung permainan, membatasi akses ke daerah penangkapan ikan, dan mungkin mengubah perikanan, semua dengan konsekuensi ekonomi yang negatif. Salvinia dapat menyumbat intake air dan mengganggu irigasi pertanian, pasokan air, dan pembangkit listrik. Ini menyediakan habitat bagi vektor penyakit manusia dengan dampak sosial ekonomi yang serius.
Di negara-negara berkembang, dampak dari Salvinia dapat menghancurkan karena gulma tikar memblokir penggunaan
Gambar 1. Salvinia molesta DS Mitchell
meliputi kolam peternakan di Texas membatasi
penggunaan komersial dan rekreasi dan menurunkan estetika. (Photography oleh T. Center.)
Saluran air untuk transportasi, memotong akses ke layanan penting, lahan pertanian, dan perburuan. Bahaya dari Salvinia tikar untuk perikanan juga bisa sangat signifikan untuk masyarakat yang bergantung pada ikan untuk konsumsi lokal (kadang-kadang sebagai sumber utama protein) atau di daerah di mana penjualan ikan merupakan sumber utama pendapatan tunai (Bennett, 1966; Thomas dan Room , 1986). Salvinia juga merupakan gulma padi yang mengurangi produksi dengan bersaing untuk air, nutrisi dan ruang (Anon., 1987). Kerusakan ekologi. Kemampuan untuk tumbuh sangat cepat (Cary dan Weerts, 1983; Mitchell dan Tur, 1975; Mitchell, 1978/9; Room, 1986) dan badan air selimut membuat Salvinia gulma agresif dan kompetitif (Gambar 2.). Awalnya, Salvinia membentuk lapisan tunggal di atas air, tetapi dengan pertumbuhan yang berkelanjutan tikar menjadi berlapis-lapis dan dapat mencapai hingga 1 m ketebalan (Thomas dan Room, 1986). Tikar tebal mendukung tanaman menjajah lainnya, dan biomassa yang tinggi dan stabilitas tikar seperti membuat mereka sulit untuk mengusir dan menghancurkan (Storrs dan Julien, 1996). Tanaman dan hewan tergantung pada air terbuka untuk mendapatkan sinar matahari, oksigen, dan ruang untuk rezeki dan pertumbuhan , atau untuk mendarat, memancing, bangunan sarang, atau kawin, mengungsi Gambar 2. Salvinia molesta DS Mitchell meliputi waterbody dan mendukung pertumbuhan spesies tanaman lain di Kakadu National Park, Australia. (Foto oleh M. Julien.) Oleh infestasi Salvinia padat. Air di bawah tikar dari Salvinia memiliki konsentrasi oksigen rendah (karena berkurangnya luas permukaan air yang tersedia untuk oksigenasi, penghambatan fotosintesis oleh tanaman terendam, dan konsumsi oksigen terlarut oleh membusuk Salvinia), karbon dioksida yang lebih tinggi dan konsentrasi hidrogen sulfida, pH rendah, dan suhu yang lebih tinggi daripada air di dekatnya terbuka (Mitchell, 1978; Thomas dan Room, 1986). Melalui tingkat pertumbuhan yang tinggi dan tingkat dekomposisi lambat, Salvinia mengurangi konsentrasi nutrisi yang dinyatakan akan tersedia untuk produsen primer dan organisme yang bergantung pada mereka (Sharma dan Goel, 1986;. Storrs dan Julien, 1996) Mats dari Salvinia menyediakan habitat yang ideal bagi Mansonia nyamuk, vektor utama kaki gajah pedesaan di Sri Lanka (Pancho dan Soerjani, 1978), dan untuk spesies nyamuk lain yang terlibat dalam transmisi ensefalitis , demam berdarah, dan malaria (Creagh, 1991-1992). Dua spesies Mansonia yang terjadi di Amerika Serikat, Mansonia dyari Belkin dan Mansonia titillans (Walker), telah terlibat dalam transmisi St. Louis ensefalitis dan Venezuela ensefalitis kuda, masing-masing (Lounibos et al., 1990). Tingkat kerugian . Penilaian yang paling rinci dari biaya yang disebabkan oleh Salvinia dilakukan di Sri Lanka menggunakan tahun 1987 sebagai tahun dasar (Doeleman, 1989). Kerugian padi, kerugian memancing, kerugian lainnya (pembangkit listrik, transportasi, mencuci dan mandi, dll), biaya kesehatan, biaya pengurangan, dan manfaat ekonomi dianggap. Tidak ada biaya lingkungan dimasukkan, tapi mereka diakui sebagai penting. Tidak ada manfaat diidentifikasi dari Salvinia. Total biaya yang terkait dengan Salvinia diperkirakan antara 24.700.000 dan 56.700.000 rupee (dalam dolar Australia, antara 0,9 dan 2,1 juta) untuk tahun 1987. Informasi ini digunakan untuk menentukan manfaat dari kontrol biologis selama 25 tahun berikutnya. Manfaat yang 53 rupee atau dolar per rupee atau dolar yang diinvestasikan, atau 1673 jam kerja per orang-jam diinvestasikan. Dengan menggunakan informasi ini sebagai panduan, kamar dan Julien (1995) memperkirakan bahwa manfaat tahunan yang diperoleh dari kontrol biologis sukses Salvinia seluruh dunia adalah sekitar $ 150 juta US Distribusi Geografis Kisaran asli Salvinia adalah daerah di tenggara Brazil (Forno dan Harley, 1979). Pembentukan eksotis pertama tercatat adalah di Sri Lanka pada tahun 1939 (Williams, 1956). Sejak itu menjadi mapan di India (Cook and Gut, 1971), Australia (Room dan Julien, 1995), Papua New Guinea (Mitchell, 1979), Kuba, Trinidad, Guyana, Columbia (Holm et al., 1979), South Afrika (Cilliers, 1991), Botswana (Edwards dan Thomas, 1977), Kenya, Zambia (Mitchell dan Tur, 1975), Namibia (Forno dan Smith, 1999), Madagaskar (Room dan Julien, 1995), Ghana dan Cote D ' Ivoire (M. Julien, pers. obs.), Indonesia (Jawa, Kalimantan, Sulawesi), Malaysia (daratan Sabah, Sarawak) (R. Chan, pers. comm.), Filipina (Pablico et al., 1989), Fiji (Kamath, 1979), dan Selandia Baru (Randall, 1996). Salvinia pertama kali dilaporkan di luar budidaya di Amerika Serikat pada tahun 1995 di sebuah kolam di tenggara Carolina Selatan (Johnson, 1995). Itu diberantas sebelum penyebaran terjadi. Itu berikutnya ditemukan di Houston, Texas, pada Mei 1998, dan kemudian di tempat lain di Texas dan Louisiana di selama tahun 1998. Selama tahun 1999 itu ditemukan di kolam dan sungai di Alabama, Arizona, California, Florida, Georgia, Hawaii, Mississippi, dan Oklahoma (Jacono et al, 2000;. lihat juga situs web Jacono ini). Salvinia sudah tersedia untuk pembelian di Amerika Serikat, khususnya melalui Internet. Informasi Latar Belakang Hama Tanaman Taksonomi Keluarga pakis air salviniaceae ditempatkan dalam urutan Hydropteridales dan terdiri dari genus tunggal, Salvinia. Sepuluh spesies Salvinia terjadi di seluruh dunia (Herzog, 1935; de la Sota, 1962, 1963, 1964, 1982; Mitchell, 1972). Tidak ada yang asli Amerika Serikat (Jacono et al., 2000) meskipun tujuh spesies berasal di Amerika (de la Sota, 1976). Salvinia molesta diberikan pengakuan sebagai spesies pada tahun 1972 (Mitchell, 1972) dan dikelompokkan dalam auriculata kompleks Salvinia, bersama-sama dengan Salvinia auriculata Aublet, Salvinia biloba Raddi, dan Salvinia herzogii de la Sota (Mitchell dan Thomas, 1972). Spesies dalam kompleks ini dicirikan oleh adanya dibagi tetapi apikal bergabung "keranjang" rambut di permukaan abaxial, yang menghasilkan penampilan "telur-pemukul seperti" (Gambar 3a.) (De la Sota, 1962; Mitchell dan Thomas, 1972; Forno, 1983). Salvinia molesta dapat dibedakan dari spesies dalam auriculata kompleks S. oleh penataan sporangia, bentuk sporocarps (Mitchell dan Thomas, 1972; Mitchell, 1972), dan oleh pola daun venation (Forno, 1983). The diterima Nama umum adalah Salvinia, tetapi juga disebut Kariba gulma, pakis air, atau Afrika Pyle (di Afrika); azolla raksasa atau azolla Australia (di Filipina); dan Salvinia raksasa, spangles air, atau mengambang pakis (di Amerika Serikat). Salvinia minima Baker, satu-satunya spesies Salvinia lain yang hadir di Amerika Serikat juga eksotis dan dapat dibedakan dengan adanya rambut dibagi pada permukaan daun abaxial yang menyebar dan bebas di ujung (Gambar. 3b). Gambar 3a. Spesies Salvinia di Amerika Serikat dapat dibedakan dengan rambut daun mereka. Dalam Salvinia molesta yang rambut membentuk 'pengocok telur' bentuk pada tips. (Foto oleh M. Julien.) Gambar 3b. Dalam Salvinia minima rambut dipisahkan di ujung. (Foto-foto oleh T. Center.) Biologi bentuk tanaman. Salvinia adalah pakis air mengambang bebas dengan rimpang horisontal tepat di bawah permukaan air (Bonnet, 1955; Room, 1983). Setiap tanaman adalah koloni ramet. Setiap ramet terdiri ruas, node, sepasang daun mengambang, terendam 'akar, dan tunas terkait. "Root" adalah daun dimodifikasi yang terlihat dan berfungsi seperti akar (Croxdale 1978, 1979, 1981). Salvinia adalah morfologi variabel, terutama dalam menanggapi tingkat crowding dan ketersediaan nutrisi. Kedua faktor sebagian besar independen satu sama lain. Ada tiga bentuk pertumbuhan, dengan kontinum antara mereka, yang berkaitan dengan tingkat crowding dialami oleh tanaman (Mitchell dan Tur, 1975). Bentuk primer (Gambar. 4a) terjadi sebagai tanaman terisolasi di awal 'menyerang' tahap kutu. Formulir ini telah kecil, oval daun kurang dari 15 mm lebar yang berbaring di permukaan air. Bentuk sekunder (Gambar. 4b) terjadi ketika tanaman telah tumbuh di atas air terbuka untuk beberapa waktu, baik secara bebas atau di tepi tikar stabil . Ruas lebih panjang, dengan lebih besar, daun yang telah bulat apeks dan variabel dalam ukuran, tapi biasanya antara 20 mm dan 50 mm lebar berbentuk perahu (sedikit keeled). Seluruh permukaan daun bawah bersentuhan dengan air. Bentuk tersier (Gambar. 4c) terjadi ketika tanaman tumbuh dalam kondisi tikar ramai dikaitkan dengan infestasi matang. Ruas yang pendek dengan daun, atau lonjong dan sangat keeled berbentuk hati yang besar hingga 60 mm lebar ketika terbuka penuh. Sisi bawah daun yang berdekatan berada dalam kontak dengan satu sama lain. Gambar 4a. Bentuk utama dari Salvinia molesta DS Mitchell. (Foto oleh M. Julien.) Gambar 4b. Bentuk sekunder Salvinia molesta DS Mitchell. (Foto oleh M. Julien.) Gambar 4c. Bentuk tersier Salvinia molesta DS Mitchell. (Foto oleh M. Julien.) Pertumbuhan dan reproduksi. Salvinia adalah pentaploid, memiliki jumlah kromosom 45, dan tidak mampu reproduksi seksual (Loyal dan Grewal, 1966). Setiap node dikenakan serangkaian hingga tiga tunas ketiak yang mengembangkan berturut-turut di bawah kondisi pertumbuhan normal (Room, 1988), dan hingga enam dalam menanggapi kerusakan (Julien dan Bourne, 1986). Jumlah tunas ketiak yang tumbuh, tikus