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Virus and Viroid Plant Pathogens

Virus and Viroid Plant Pathogens. Kenneth L. Johnson II USDA National Needs Fellow University of Florida Plant Medicine Program IPM Florida- IPM Apprentice Kirk W. Martin SM(NRCM), CBSP USDA National Needs Fellow University of Florida Plant Medicine Program

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Virus and Viroid Plant Pathogens

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  1. Virus and ViroidPlant Pathogens Kenneth L. Johnson II USDA National Needs Fellow University of Florida Plant Medicine Program IPM Florida- IPM Apprentice Kirk W. Martin SM(NRCM), CBSP USDA National Needs Fellow University of Florida Plant Medicine Program IPM Florida-IPM Technical Information Specialist

  2. Begomovirus-Bean golden yellow mosaic virus Family: Geminiviridae Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid is elongated and exhibits icosahedral symmetry. The capsid is geminate and has a diameter of 18-20 nm. Capsids appear hexagonal in outline. The capsomer arrangement is not obvious. The capsid consists of 22 capsomers. With a length of dimers 30 nm. (ICTV database) R.G. Milne, IstitutodiVirologia, CRN, Torino, Italy

  3. Begomovirus-Bean golden yellow mosaic virus Family: Geminiviridae Host(s): Wild bush bean, Macroptiliumlathyroides, Common bush bean, Phaseolusvulgaris, Sieva bean, P. lunatus, Threelobe false mallow, Malvastrumcoromandelianum Howard F. Schwartz, Colorado State University, Bugwood.org Leaf symptoms: vein yellow net, interveinalchlorosis Howard F. Schwartz, Colorado State University, Bugwood.org

  4. Begomovirus-Bean golden yellow mosaic virus Family: Geminiviridae Host(s): Wild bush bean, Macroptiliumlathyroides, Common bush bean, Phaseolusvulgaris, Sieva bean, P. lunatus, Threelobe false mallow, Malvastrumcoromandelianum Howard F. Schwartz, Colorado State University, Bugwood.org Leaf symptoms: vein yellow net, interveinalchlorosis Howard F. Schwartz, Colorado State University, Bugwood.org

  5. Begomovirus-Bean golden yellow mosaic virus Family: Geminiviridae Diagnostic viral inclusions: Nuclear Rounded dense bodies Ring-shaped (rare) Brittle crystals UF IFAS Extension Plant Disease Clinic UF IFAS Extension Plant Disease Clinic UF IFAS Extension Plant Disease Clinic

  6. Closterovirus-Citrus tristeza virus (CTV) Family: Closteroviridae Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a length of 2000 nm and a width of 12 nm. M. Bar-Joseph Volcani Centre, Bet Dagan, Israel

  7. Closterovirus-Citrus tristeza virus (CTV) Family: Closteroviridae Host(s): Citrus ssp. grafted onto Citrus aurantium (sour orange) root stock — quick decline, pitted stems. C. paradisi (grapefruit) — stunt. C. aurantifolia (lime) — die-back. C. aurantifolia (Seville orange) — seedling yellows. C. reticulata (mandarin) — decline. Aeglopsischevalieri, Afraeglepaniculata (Nigerian powder-flask-fruit )), Pamburusmissionis, Passifloragracilis(Annual passionflower), Citropsisgilletiana, Microcitrusaustralis Disorders: Tristeza Stem-pitting Seedling-yellows Lime dieback Diseases: Quick decline L. Navarro, InstitutoValenciano de InvestigacionesAgrarias, Bugwood.org

  8. Closterovirus-Citrus tristeza virus (CTV) Family: Closteroviridae Symptomology Sweet orange-(Sweet orange stem pitting strains) Sour orange-(Seedling yellows) severe stunting and yellowing Grapefruit-(Seedling yellows)severe stunting and yellowing , (Stem-pitting) stunted, the fruit is small and misshapen, and yields are considerably reduced; the wood of the trunk and large limbs is pitted with longitudinal depressions; in some instances, the main scaffold branches are twisted and distorted. Lime-(Lime die-back strain) vein flecking on young leaves, severe pitting of wood of twigs and branches, stunting of trees, and die-back with eventual death Lemon-(Seedling yellows) severe stunting and yellowing Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

  9. Brown citrus aphid, Toxopteracitricida Lyle Buss, University of Florida Closterovirus-Citrus tristeza virus (CTV) Melon aphid, Aphis gossypii Lyle Buss, University of Florida Family: Closteroviridae Vectors: Brown citrus aphid, Toxopteracitricida and Melon aphid, Aphis gossypii. Diagnostic techniques: Visual symptoms Indexing on biological indicators Management: Disease-resistant cultivars Disease-resistant rootstocks (will not work on plants that virus attacks directly i.e. certain lime, grapefruit, pummelos, Pera sweet orange and others (Reuther, 1978) Possible cross-protection from less mild strains of tristeza virus L. Navarro, InstitutoValenciano de InvestigacionesAgrarias, Bugwood.org Tristeza virus affected fruit on right

  10. Closterovirus-Citrus tristeza virus (CTV) Family: Closteroviridae Diagnostic techniques: Visual symptoms Indexing on biological indicators Diagnostic viral inclusions: All cytoplasmic Para-crystals Banded bodies Densely stained phloem with many vacuoles. UF IFAS Extension Plant Disease Clinic CTV petiole inclusions UF IFAS Extension Plant Disease Clinic CTV stem inclusions UF IFAS Extension Plant Disease Clinic CTV root inclusions

  11. Cucumovirus-Cucumber mosaic virus (CMV) Family: Bromoviridae Description: Virions consist of a capsid. Virus capsid is not enveloped, round with icosahedral symmetry. The isometric capsid has a diameter of 29-29.33-30 nm. Capsids appear round, or hexagonal in outline. The capsomer arrangement is clearly visible, or is not obvious. The capsid consists of 32 capsomers. Virus preparations contain more than one particle component. Capsids all have the same appearance. (ICTV database). R.G. Milne, IstitutodiVirologia, CRN, Torino, Italy.

  12. Cucumovirus-Cucumber mosaic virus (CMV) Family: Bromoviridae Hosts: Cucumber, Cucumissativus and many other cucurbits — mosaics and stunting, reduced fruit yield. Tomato, Lycopersiconesculentum — mosaic, reduction of leaf laminae ("fernleaf") and stunting. Spinach, Spinaciaoleracea — severe chlorosis and stunting. David B. Langston, University of Georgia, Bugwood.org CMV Infected cucumber William M. Brown Jr., Bugwood.org CMV infected celery

  13. Cucumovirus-Cucumber mosaic virus (CMV) Family: Bromoviridae Vectors: Aphids transmit in a non-persistent manner Cucumber infected by Cucumber mosaic virus William M. Brown Jr., Bugwood.org William M. Brown Jr., Bugwood.org CMV infected cucumbers

  14. Cucumovirus-Cucumber mosaic virus (CMV) Family: Bromoviridae Diagnostic viral inclusions: Cytoplasmic Vacuolate Vesiculate Crystalline cubes Spheres Hollow spheres Dr. R. G. Christie, UF IFAS Department of Plant Pathology UF IFAS Extension Plant Disease Clinic Dr. R. G. Christie, UF IFAS Department of Plant Pathology

  15. Begomovirus-Cucurbit leaf crumple virus (CuLCrV) Family: Geminiviridae Description: No official description General Begomovirusdescription: Virions consist of a capsid. Virus capsid is not enveloped. Capsid is elongated and exhibits icosahedral symmetry. The capsid is geminate, or prolate in shape and has a diameter of 15-20 nm. Capsids appear round, or hexagonal in outline. The capsomer arrangement is clearly visible, or is not obvious. The capsid consists of 22 capsomers. With a length of 25-30 nm. Zucchini squash infected with Cucurbit leaf crumple virus. Note silverleaf symptoms in background due to feeding of immature whiteflies. http://edis.ifas.ufl.edu/in716

  16. Begomovirus-Cucurbit leaf crumple virus (CuLCrV) Family: Geminiviridae Description: Hosts: Watermelon, Citrulluslanatus Cantaloupe and Honeydew melon, Cucumismelo Squash and pumpkins, Cucurbita palmate and C. maxima, C. pepo Florida Department of Agriculture and Consumer Services Zucchini squash infected with Cucurbit leaf crumple virus. Note silverleaf symptoms in background due to feeding of immature whiteflies. http://edis.ifas.ufl.edu/in716

  17. Begomovirus-Cucurbit leaf crumple virus (CuLCrV) Family: Geminiviridae Cucurbits that were not susceptible were acorn squash, ananas melon, butternut squash, casaba melon, Galia melon, golden crenshaw melon, and honeydew melon. Non-susceptible crops included cotton, pepper, soybean, and tomato. Florida Department of Agriculture and Consumer Services Cucurbit leaf crumple virus symptoms on cucumber Cucurbit leaf crumple virus symptoms on yellow straight-necked squash

  18. Begomovirus-Cucurbit leaf crumple virus (CuLCrV) Vector: Silverleaf whitefly, Bemisiaargentifolii Silverleaf whitefly, Bemisiaargentifolii-vector of cucurbit leaf crumple virus. Photo by Lyle Buss-University of Florida

  19. Begomovirus-Cucurbit leaf crumple virus (CuLCrV) Bean golden mosaic virus inclusions (pictured) look very similar to Cucurbit leaf crumple virus Diagnostic viral inclusions: Nuclear Rounded dense bodies Ring-shaped (rare) Brittle Crystals R. Cullen and M. Gooch, UF IFAS Extension Plant Disease Clinic Bean golden mosaic virus inclusions (pictured) close-up R. Cullen and M. Gooch, UF IFAS Extension Plant Disease Clinic

  20. Potexvirus-Cymbidium mosaic virus (CymMV) Family: Flexiviridae Description: Virions have a simple construction (round or elongated or spherical, unenvelopedvirions); consist(s) of a capsid (including inner and outer capsid). Virus capsid is not enveloped. Capsid/nucleocapsid is elongated; exhibits helical symmetry; capsid. Capsid shape of elongated unenvelopedvirion or tail of phage is filamentous, is flexuous. Elongated capsid, nucleocapsid or phage tail is cross-striated. Elongated capsids, nucleocapsids or tails have only or longest length(s) of 470 to 580 nm; is 13 nm wide. Axial canal is distinct or indistinct, 3.4 to 12 with median 6.3 nm in diameter. Basic helix is obvious or obscure. Pitch of helix is 2.8 to 3.5 with median 3.331 nm. Crude virus preparation contains few virions or many virions. R. I. B. FranckiDepartment of Plant Pathology, Waite Agricultural Research Institute, University of Adelaide, South Australia Cymbidium mosaic virus Virus particles from purified preparation in uranyl acetate. Bar represents 500 nm. http://www.dpvweb.net/dpv/showdpv.php?dpvno=27

  21. Potexvirus-Cymbidium mosaic virus (CymMV) Cymbidium mosaic virus symptoms Family: Flexiviridae Hosts: Cymbidium ssp. — mosaic, necrosis. Cattleya ssp. — mosaic, flower necrosis. Phalaenopsis ssp. — mosaic, water soaked local lesions. Vanda ssp. — chlorotic flecks. Epidendrum ssp., Laelia ssp., Laeliocattleya ssp., Oncidium ssp., Zygopetalum ssp., Vanilla fragrans Florida Department of Agriculture and Consumer Services Cymbidium mosaic symptoms in Cymbidium leaves. http://ucce.ucdavis.edu/files/repositoryfiles/ca601p3-71680.pdf

  22. Potexvirus-Cymbidium mosaic virus (CymMV) Family: Flexiviridae Viral inclusions: Widely distributed in host tissues Aggregates of virus particles Long axis parallel Banded bodies Can be susceptible to destruction Dense bodies Para-crystals Florida Department of Agriculture and Consumer Services Cymbidium mosaic virus-banded inclusions Florida Department of Agriculture and Consumer Services Cymbidium mosaic viral inclusions (see arrows)

  23. Potyvirus-Dasheen mosaic virus (DsMV) Family: Potyviridae Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 750 nm (approximately). Axial canal is indistinct. Basic helix is obscure. Zettler, Univ. Florida 1970 Filamentous virus particles mounted in phosphotungatate..

  24. Potyvirus-Dasheen mosaic virus (DsMV) Family: Potyviridae Hosts: Aglaonema, Alocasia, Amorphophallus, Arisaema, Caladium, Cyrtosperma ssp. — mosaic. Cryptocoryne, Dieffenbachia, Philodendron, Richardia, Zantedeschia ssp. — mosaic and leaf malformation. Colocasia, Xanthosoma ssp. — mosaic, chlorotic feathering. Comments on host and host range: there are conflicting reports on the susceptibility of non-aroids; in European studies some are susceptible, but, in tests Florida and Venezuela, non-aroids were not infected (Zettler and Hartman, 1986). Photo by: F.W. Zettler Chlorosis of Philodendron selloumleaf N.J.Ko Florida Department of Agriculture and Consumer Services Dasheen mosaic virus in Taro

  25. Potyvirus-Dasheen mosaic virus (DsMV) Family: Potyviridae Hosts: Aglaonema, Alocasia, Amorphophallus, Arisaema, Caladium, Cyrtosperma ssp. — mosaic. Cryptocoryne, Dieffenbachia, Philodendron, Richardia, Zantedeschia ssp. — mosaic and leaf malformation. Colocasia, Xanthosoma ssp. — mosaic, chlorotic feathering. Comments on host and host range: there are conflicting reports on the susceptibility of non-aroids; in European studies some are susceptible, but, in tests Florida and Venezuela, non-aroids were not infected (Zettler and Hartman, 1986). Photo by: F.W. Zettler Mosaic and distortion of P. selloumleaf N.J.Ko Florida Department of Agriculture and Consumer Services Dasheen mosaic virus in Dieffenbachia

  26. Potyvirus-Dasheen mosaic virus (DsMV) Family: Potyviridae Hosts: Aglaonema, Alocasia, Amorphophallus, Arisaema, Caladium, Cyrtosperma ssp. — mosaic. Cryptocoryne, Dieffenbachia, Philodendron, Richardia, Zantedeschia ssp. — mosaic and leaf malformation. Colocasia, Xanthosoma ssp. — mosaic, chlorotic feathering. Comments on host and host range: there are conflicting reports on the susceptibility of non-aroids; in European studies some are susceptible, but, in tests Florida and Venezuela, non-aroids were not infected (Zettler and Hartman, 1986). ICTVdB - The Universal Virus Database Mosaic of taro (Colocasiaesculenta) leaf

  27. Potyvirus-Dasheen mosaic virus (DsMV) Family: Potyviridae Diagnostic viral inclusions: Cytoplasmiccylindirical inclusions Proteinaceous Pinwheel and scrolls in C-section Laminated aggregate Amorphous cytoplasmic inclusions Protein & ribonucleo-protein Irregular in shape Vary in size Vary in number Nuclear inclusions Proteinaceous Most crystalline Cytoplasmicmicrobodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirusinfections Florida Department of Agriculture and Consumer Services I = Cylindrical Inclusions N=Nucleus ICTVdB - The Universal Virus Database Electron micrograph of cylindrical inclusions in cell of calla lily (Zantedeschia elliotiana). Bar represents 500 nm.

  28. Hostuviroid-Hop stunt viroid (Citrus viroid II) (HSVd) Family: Pospiviroidae Description: Viroids are unencapsidated, low molecular weight, circular, single-stranded infectious RNAs pathogenic to plants. Sequences are the primary basis for comparison. The sequence of the central conserved region allows all characterisedviroids to be classed into four groups. Variation occurs within each viroid "species" and an arbitrary level of 90% sequence similarity currently separates variants from species. ICTVdB - The Universal Virus Database Photo of potato spindle tuber viroidwhich closely resembles Hop stunt viroid (Citrus viroid II)

  29. Hostuviroid-Hop stunt viroid (Citrus viroid II) (HSVd) Family: Pospiviroidae Hosts:     Hop stunt viroid     Hop stunt viroid - almond     Hop stunt viroid - apricot     Hop stunt viroid - citrus     Hop stunt viroid - cucumber     Hop stunt viroid - grapevine     Hop stunt viroid - peach     Hop stunt viroid - pear     Hop stunt viroid - plum     Citrus cachexiaviroid     Cucumber pale fruit viroid     Peach dapple viroid     Plum dapple viroid Green streaks observed under cracks induced by Hop stunt viroid and Citrus viroid IV in trifoliate orange photo by C. Vernière et al. http://www.apsnet.org/publications/imageresources/Pages/Nov_88-11-1.aspx David Gent, USDA Agricultural Research Service, Bugwood.org Common hops (HumuluslupulusL.)A common hop plant showing symptoms of hop stunt viroid infection in a field at Oregon, USA.

  30. Tospovirus-Impatiens necrotic spot virus (INSV) Family: Bunyaviridae Description: Virions consist of an envelope and a nucleocapsid. Virus capsid is enveloped. Virions are spherical to pleomorphic. Surface projections are embedded in a lipid bilayer that is 5 nm thick. Capsid/nucleocapsid is elongated with helical symmetry. The ribonucleocapsid is filamentous and has a width of 2-2.5 nm. Nucleocapsids are circular.

  31. Tospovirus-Impatiens necrotic spot virus (INSV) Family: Bunyaviridae Hosts: Impatiens spp. most leaves symptomless, some necrotic spots with necrotic rings in young leaves. Other hosts: Gloxinia Gerbera daisy Oncidium orchid Chrysanthemum Tomato Coleus Wild geranium Department of Plant Pathology Archive, North Carolina State University, Bugwood.org Impatiens necrotic spot virus symptoms on chrysanthemum Department of Plant Pathology Archive, North Carolina State University, Bugwood.org Impatients necrotic spot virus symptoms on coleus

  32. Tospovirus-Impatiens necrotic spot virus (INSV) Family: Bunyaviridae Hosts: Impatiens spp. most leaves symptomless, some necrotic spots with necrotic rings in young leaves. Other hosts: Gloxinia Gerbera daisy Oncidium orchid Chrysanthemum Tomato Coleus Wild geranium Department of Plant Pathology Archive, North Carolina State University, Bugwood.org Impatiens necrotic spot virus symptoms on gloxinia Mary Ann Hansen, Virginia Polytechnic Institute and State University, Bugwood.org Impatients necrotic spot virus symptoms on tomato fruit

  33. Tospovirus-Impatiens necrotic spot virus (INSV) Family: Bunyaviridae Vector: Western flower thrips, Frankliniellaoccidentalis Lyle Buss University of Florida

  34. Tospovirus-Impatiens necrotic spot virus (INSV) Family: Bunyaviridae Diagnostic viral inclusions: Vacuolate Dense, irregular with projections Crystalline All photographs by Florida Department of Agriculture and Consumer Services

  35. Tobamovirus-Odontoglossumringspot virus (ORSV) Family: Unassigned Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is rod-shaped, straight with a clear modal length with a length of mostly 300 nm (but also shorter, broken virions, width of 18 nm. Axial canal is distinct. ICTVdB - The Universal Virus Database

  36. Tobamovirus-Odontoglossumringspot virus (ORSV) Family: Unassigned Hosts: Vector: Virus is not transmitted by a vector. Virus is transmitted by mechanical inoculation. Juliana Frettas-Astua Florida Department of Agriculture and Consumer Services Juliana Frettas-Astua Florida Department of Agriculture and Consumer Services

  37. Tobamovirus-Odontoglossumringspot virus (ORSV) Family: Unassigned Diagnostic viral inclusions: All cytoplasmic Hexagonal plates Virus particles Stacked plates Virus particles Paracrystals Virus particles - old infection X - Bodies Vacuolate Photograph bu Nan-Jing Ko Tobamovirus inclusions stain in Azure A stain with heat only. Photograph by Nan-Jing Ko Photograph bu Nan-Jing Ko Inclusions stained with Orange Green

  38. Potyvirus-Papaya ringspot virus (PRSV) Family: Potyviridae Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 760-800 nm and a width of 12 nm. Alberto Pantoja, USDA Agricultural Research Service, Bugwood.org

  39. Potyvirus-Papaya ringspot virus (PRSV) Family: Potyviridae Hosts: Vector: Virus is transmitted by aphids. Virus is also transmitted by mechanical inoculation; not transmitted by seeds. Alberto Pantoja, USDA Agricultural Research Service, Bugwood.org

  40. Potyvirus-Papaya ringspot virus (PRSV) Family: Potyviridae Diagnostic viral inclusions: Cytoplasmiccylindirical inclusions Proteinaceous Pinwheel and scrolls in C-section Laminated aggregate Amorphous cytoplasmic inclusions Protein & ribonucleo-protein Irregular in shape Vary in size Vary in number Nuclear inclusions Proteinaceous Most crystalline Cytoplasmicmicrobodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirusinfections UF IFAS Extension Plant Disease Clinic

  41. Pospiviroid-Potato spindle tuber viroid (PSTVd) Family: Pospiviroidae Hosts: Nucleic acid is non-encapsidated, circular, single-stranded RNA ICTVdB - The Universal Virus Database Potato spindle tuber viroid

  42. Pospiviroid-Potato spindle tuber viroid (PSTVd) Family: Pospiviroidae Hosts: Potato, Solanumtuberosum Tomato, Solanumesculentum R.P. Singh, Bugwood.org Potato cv ‘Kennebec’, Solanumtuberosum, center plant infected with Potato spindle tuber viroid, outer two plants are healthy Central Science Laboratory, Harpenden Archive, British Crown, Bugwood.org Tomato, Solanumesculentuminfected by Potato spindle tuber viroid

  43. Pospiviroid-Potato spindle tuber viroid (PSTVd) Family: Pospiviroidae Hosts: Potato, Solanumtuberosum Tomato, Solanumesculentum Plant Protection Service Archive, Plant Protection Service, Bugwood.org Potatoes infected with potato spindle tuber viroid. Healthy potato on left others diseased USDA Agricultural Research Service Archive, USDA ARS, Bugwood.org First and third rows of potatoes from top are healthy; second and fourth rows are infected with the potato spindle tuber viroid

  44. Potyvirus-Potato virus Y (PVY) Family: Potyviridae Description: Virions consist of a capsid. Virus capsid is not enveloped. Capsid/nucleocapsid is elongated with helical symmetry. The capsid is filamentous, flexuous with a clear modal length with a length of 684 nm (from purified preparations (Delgado-Sanchez and Grogan, 1966)), or 730 nm and a width of 11 nm. Axial canal is indistinct; 2-3 nm in diameter. Basic helix is obscure. Pitch of helix is 3.3 nm (Varmaet al., 1968). Rothamsted Research. Potato virus Y

  45. Potyvirus-Potato virus Y (PVY) Family: Potyviridae Hosts: Potato, Solanumtuberosum Tobacco, Nicotianatabacum Pepper, Capsicum annuum Vector: transmitted by aphids, mechanical means or transmission by grafting. Bruce Watt, University of Maine, Bugwood.org Rugose leaf symptoms on potato infected with potato virus Y Bruce Watt, University of Maine, Bugwood.org Potato infected with potato virus Y

  46. Cylindrical Amorphous Microcrystals Potyvirus-Potato virus Y (PVY) Family: Potyviridae Diagnostic viral inclusions: Cytoplasmiccylindirical inclusions Proteinaceous Pinwheel and scrolls in C-section Laminated aggregate Amorphous cytoplasmic inclusions Protein & ribonucleo-protein Irregular in shape Vary in size Vary in number Nuclear inclusions Proteinaceous Most crystalline Cytoplasmicmicrobodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirusinfections UF IFAS Extension Plant Disease Clinic UF IFAS Extension Plant Disease Clinic Stomata guard cells filled with inclusions of PVY

  47. Ipomovirus-Squash vein yellowing virus (SqVYV) Family: Potyviridae Description: The virus, for which the name Squash vein yellowing virus (SqVYV) is proposed, has flexuous rod-shaped particles of ~840 nm in length.

  48. Ipomovirus-Squash vein yellowing virus (SqVYV) Family: Potyviridae Squash Vein Yellowing Virus, Causal Agent of Watermelon Vine Decline in Florida Hosts: The host range of SqVYV appears to be limited to cucurbits including two weedy varieties of cucurbits found in Florida, Momordicacharantia L. (Balsam-apple) and Melothriapendula L. (creeping cucumber) (Adkins et al. 2008). These weeds may be important reservoirs for SqVYV and help it to survive between crops. Vectors: Whitefly, Bemesiatabaci Scott Adkins, 2008 . Plant Disease Early symptoms of WVD. Photography credit: Scott Adkins http://www.freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407.pdf Scott Adkins,, FDACS DPI Symptoms several weeks later. Photography credit: Scott Adkins http://www.freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407.pdf

  49. Ipomovirus-Squash vein yellowing virus (SqVYV) Family: Potyviridae Hosts: The host range of SqVYV appears to be limited to cucurbits including two weedy varieties of cucurbits found in Florida, Momordicacharantia L. (Balsam-apple) and Melothriapendula L. (creeping cucumber) (Adkins et al. 2008). These weeds may be important reservoirs for SqVYV and help it to survive between crops. Vectors: Whitefly, Bemesiatabaci Scott Adkins, 2008 . Plant Disease Melothriapendulaa cucurbit weed that can potentially serve as a viral reservoir Scott Adkins,, FDACS DPI Watermelon rind damaged by the Squash vein yellowing virus causing WVD symptoms. Photography credit: Scott Adkins http://www.freshfromflorida.com/pi/enpp/pathology/pathcirc/pp407.pdf

  50. Ipomovirus-Squash vein yellowing virus (SqVYV) Family: Potyviridae Diagnostic viral inclusions: Cytoplasmiccylindirical inclusions Proteinaceous Pinwheel and scrolls in C-section Laminated aggregate Amorphous cytoplasmic inclusions Protein & ribonucleo-protein Irregular in shape Vary in size Vary in number Nuclear inclusions Proteinaceous Most crystalline Cytoplasmicmicrobodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirusinfections Florida Department of Agriculture and Consumer Svcs., Department of Plant Industry CI=Cylindrical inclusions; N=Nucleus Squash vein yellowing virus http://www.freshfromflorida.com/pi/enpp/pathology/florida_viruses/Cucurbits/SqVYV/SqVYVpage.htm

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