Virus and Viroid Plant Pathogens

Name: Virus and Viroid Plant Pathogens
Uploaded: 2017-06-23T19:58:30+00:00
Duration: PTH1M12S9
Channel: Stephanie Hood
Description: 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 IPM Florida-IPM Technical Information Specialist

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 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, Istituto di Virologia, CRN, Torino, Italy

Family: Geminiviridae Host(s): Wild bush bean, Macroptilium lathyroides, Common bush bean, Phaseolus vulgaris, Sieva bean, P. lunatus, Threelobe false mallow, Malvastrum coromandelianum Howard F. Schwartz, Colorado State University, Bugwood.org Leaf symptoms: vein yellow net, interveinal chlorosis Howard F. Schwartz, Colorado State University, Bugwood.org

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

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

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. Aeglopsis chevalieri, Afraegle paniculata (Nigerian powder-flask-fruit )), Pamburus missionis, Passiflora gracilis (Annual passionflower), Citropsis gilletiana, Microcitrus australis Disorders: Tristeza Stem-pitting Seedling-yellows Lime dieback Diseases: Quick decline L. Navarro, Instituto Valenciano de Investigaciones Agrarias, Bugwood.org

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

Brown citrus aphid, Toxoptera citricida 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, Toxoptera citricida 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, Instituto Valenciano de Investigaciones Agrarias, Bugwood.org Tristeza virus affected fruit on right

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

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 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, Istituto di Virologia, CRN, Torino, Italy.

Family: Bromoviridae Hosts: Cucumber, Cucumis sativus and many other cucurbits — mosaics and stunting, reduced fruit yield. Tomato, Lycopersicon esculentum — mosaic, reduction of leaf laminae ("fernleaf") and stunting. Spinach, Spinacia oleracea — severe chlorosis and stunting. David B. Langston, University of Georgia, Bugwood.org CMV Infected cucumber William M. Brown Jr., Bugwood.org CMV infected celery

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

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

Begomovirus-Cucurbit leaf crumple virus (CuLCrV)
Family: Geminiviridae Description: No official description General Begomovirus description: 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 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 nm. Zucchini squash infected with Cucurbit leaf crumple virus. Note silverleaf symptoms in background due to feeding of immature whiteflies.

Family: Geminiviridae Description: Hosts: Watermelon, Citrullus lanatus Cantaloupe and Honeydew melon, Cucumis melo 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.

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

Vector: Silverleaf whitefly, Bemisia argentifolii Silverleaf whitefly, Bemisia argentifolii-vector of cucurbit leaf crumple virus. Photo by Lyle Buss-University of Florida

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

Potexvirus-Cymbidium mosaic virus (CymMV)
Family: Flexiviridae Description: Virions have a simple construction (round or elongated or spherical, unenveloped virions); 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 unenveloped virion 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 nm. Crude virus preparation contains few virions or many virions. R. I. B. Francki Department 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.

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.

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)

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..

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 selloum leaf N.J.Ko Florida Department of Agriculture and Consumer Services Dasheen mosaic virus in Taro

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. selloum leaf N.J.Ko Florida Department of Agriculture and Consumer Services Dasheen mosaic virus in Dieffenbachia

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 (Colocasia esculenta) leaf

Family: Potyviridae Diagnostic viral inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections 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.

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 characterised viroids 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 viroid which closely resembles Hop stunt viroid (Citrus viroid II)

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 cachexia viroid 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. David Gent, USDA Agricultural Research Service, Bugwood.org Common hops (Humulus lupulus L.) A common hop plant showing symptoms of hop stunt viroid infection in a field at Oregon, USA.

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 nm. Nucleocapsids are circular.

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

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

Family: Bunyaviridae Vector: Western flower thrips, Frankliniella occidentalis Lyle Buss University of Florida

Family: Bunyaviridae Diagnostic viral inclusions: Vacuolate Dense, irregular with projections Crystalline All photographs by Florida Department of Agriculture and Consumer Services

Tobamovirus-Odontoglossum ringspot 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

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

Family: Unassigned Diagnostic viral inclusions: All cytoplasmic Hexagonal plates Virus particles Stacked plates 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

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 nm and a width of 12 nm. Alberto Pantoja, USDA Agricultural Research Service, Bugwood.org

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

Family: Potyviridae Diagnostic viral inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections UF IFAS Extension Plant Disease Clinic

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

Family: Pospiviroidae Hosts: Potato, Solanum tuberosum Tomato, Solanum esculentum R.P. Singh, Bugwood.org Potato cv ‘Kennebec’, Solanum tuberosum, center plant infected with Potato spindle tuber viroid, outer two plants are healthy Central Science Laboratory, Harpenden Archive, British Crown, Bugwood.org Tomato, Solanum esculentum infected by Potato spindle tuber viroid

Family: Pospiviroidae Hosts: Potato, Solanum tuberosum Tomato, Solanum esculentum 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

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 (Varma et al., 1968). Rothamsted Research. Potato virus Y

Family: Potyviridae Hosts: Potato, Solanum tuberosum Tobacco, Nicotiana tabacum 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

Cylindrical Amorphous Family: Potyviridae Diagnostic viral inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections Microcrystals UF IFAS Extension Plant Disease Clinic UF IFAS Extension Plant Disease Clinic Stomata guard cells filled with inclusions of PVY

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.

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, Momordica charantia L. (Balsam-apple) and Melothria pendula L. (creeping cucumber) (Adkins et al. 2008). These weeds may be important reservoirs for SqVYV and help it to survive between crops. Vectors: Whitefly, Bemesia tabaci Scott Adkins, Plant Disease Early symptoms of WVD. Photography credit: Scott Adkins Scott Adkins,, FDACS DPI Symptoms several weeks later. Photography credit: Scott Adkins

Family: Potyviridae Hosts: The host range of SqVYV appears to be limited to cucurbits including two weedy varieties of cucurbits found in Florida, Momordica charantia L. (Balsam-apple) and Melothria pendula L. (creeping cucumber) (Adkins et al. 2008). These weeds may be important reservoirs for SqVYV and help it to survive between crops. Vectors: Whitefly, Bemesia tabaci Scott Adkins, Plant Disease Melothria pendula a 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

Family: Potyviridae Diagnostic viral inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections Florida Department of Agriculture and Consumer Svcs., Department of Plant Industry CI=Cylindrical inclusions; N=Nucleus Squash vein yellowing virus

Potyvirus-Sugarcane mosaic virus (SCMV)
Family: Potyviridae Description: Morphology 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 nm and a width of 13 nm. Axial canal is indistinct. Basic helix is obscure. Filamentous particles of sugarcane mosaic virus strain H mounted in phosphotungstate. Bar represents 200 nm.

Family: Potyviridae Hosts: Saccharum sp. — systemic mosaic. Sorghum bicolor — necrotic local lesion, then systemic mosaic, necrosis. S. halepense — systemic mosaic. Zea mays — systemic mosaic, ringspots. Most dicotyledonous plants. Photograph 1 Sugarcane variety C.P systemically infected by sugarcane mosaic virus strain B. (Courtesy A. G. Gillaspie.) Photograph 2 Sugarcane variety C.P systemically infected by sugarcane mosaic virus strain D. (Courtesy A. G. Gillaspie.) Photograph 6 Systemic necrosis produced by sugarcane mosaic virus strain A in sorghum. Photograph 7 Local necrotic lesions produced in Atlas sorghum by sugarcane mosaic virus strain E. (Courtesy J. L. Dean.)

Family: Potyviridae Vector: Virus is transmitted non-persitently by the aphids: Dactynotus ambrosiae, Rusty plum aphid, Hysteroneura setariae, Corn leaf aphid, Rhopalosiphum maidis, Toxoptera graminum. Transmission: Virus is transmitted by mechanical inoculation; transmitted by grafting; transmitted by seeds; not transmitted by pollen. Merle Shepard, Gerald R.Carner, and P.A.C Ooi, Insects and their Natural Enemies Associated with Vegetables and Soybean in Southeast Asia, Bugwood.org Corn leaf aphid , Rhopalosiphum maidis

Family: Potyviridae Diagnostic viral inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections Cylindrical inclusions of sugar cane mosaic in Zea mays (corn). The inclusion at the far right is next to a nucleus.

Potyvirus-Tobacco etch virus (TEV)
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 nm and a width of nm. Basic helix is obvious (in UF). Potyvirus photograph from IACR Rothamsted

Family: Potyviridae Hosts: Cassia obtusifolia — leaf mottling, malformation and necrosis, stunting and reduced seed yield. Capsicum annuum — mottling, mosaic and leaf malformation, fruit malformation, stunting. Datura stramonium — leaf mottling, vein banding and malformation, suppression of fruit spines. Lycopersicon esculentum — leaf mottling and distortion, severe yield reductions. Nicotiana tabacum — mottling and necrotic leaf etching. Physalis ssp. — leaf chlorosis. Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Family: Potyviridae Hosts: Cassia obtusifolia — leaf mottling, malformation and necrosis, stunting and reduced seed yield. Capsicum annuum — mottling, mosaic and leaf malformation, fruit malformation, stunting. Datura stramonium — leaf mottling, vein banding and malformation, suppression of fruit spines. Lycopersicon esculentum — leaf mottling and distortion, severe yield reductions. Nicotiana tabacum — mottling and necrotic leaf etching. Physalis ssp. — leaf chlorosis. Clemson University - USDA Cooperative Extension Slide Series, Bugwood.org Tobacco etch virus symptoms on tobacco

Family: Potyviridae Vector: Aphids especially Green peach aphid, Myzus persicae Lyle Buss University of Florida Winged green peach aphid Myzus persicae Lyle Buss University of Florida Adult female green peach aphid Myzus persicae

Pinwheel Inclusions Microcrystals Family: Potyviridae Diagnostic viral inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections Nucleus UF IFAS Extension Plant Disease Clinic Inclusion

Tobamovirus-Tobacco mosaic virus (TMV)
Family: No family assigned 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 300 nm and a width of 18 nm. Axial canal is distinct; 2 nm in diameter. Basic helix is obvious. Pitch of helix is 2.3 nm. Dr. Robley Williams

Family: No family assigned Host: Nicotiana tabacum — leaf mosaic, severe crop losses. Also found in many other plant species. Vector/Transmission: Virus is not transmitted by a vector. Virus is transmitted by mechanical inoculation; transmitted by grafting; transmitted by contact between hosts; transmitted by seeds (occasionally transmitted through the testa, but not through the embryo, not transmitted by pollen. Transmitted by dodder, Cuscuta campestris, C. japonica and C. subinclusa Milton Zaitlin Symptoms of TMV in Nicotiana tabacum cv Turkish Samsun. Photographed three weeks post-inoculation. Milton Zaitlin Local necrotic lesions produced upon TMV infection in Nicotiana tabacum of the NN genotype. Photographed one week post-inoculation.

Family: No family assigned Diagnostic viral inclusions: All cytoplasmic Hexagonal plates Virus particles Stacked plates Paracrystals Virus particles – old infection X - Bodies Vacuolate Dr. R. G. Christie, UF IFAS Department of Plant Pathology

Family: No family assigned Diagnostic viral inclusions: All cytoplasmic Hexagonal plates Virus particles Stacked plates Paracrystals Virus particles – old infection X - Bodies Vacuolate UF IFAS Extension Plant Disease Clinic Dr. R. G. Christie, UF IFAS Department of Plant Pathology

Tobravirus-Tobacco rattle virus (TRV)
Family: No family assigned 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 nm (T), or nm (B, width of 22 nm. Axial canal is distinct; 4 nm in diameter. Basic helix is obvious. Pitch of helix is 2.5 nm. IACR Rothamsted

Family: No family assigned Hosts: Stellaria media, Viola arvensis — few symptoms, mottling. Beta vulgaris, Spinacia oleracea — chlorotic or necrotic local lesions; systemic mottle. Capsicum annuum — ringspots or line patterns. Solanum tuberosum — necrotic local lesions; systemic chlorotic or necrotic spots and streaks. Nicotiana tabacum — necrotic local lesions, necrotic or chlorotic ringspots; systemic necrosis, ringspots or line patterns, mottling. Narcissus pseudonarcissus, Tulipa sp., Hyacinthus sp. — mottling. G. Chastagner1 and H. R. Pappu, Washington State Univ. Symptoms of Tobacco rattle virus on peony Ben Lockhart, University of Minnesota Extension Tobacco Rattle virus on hosta 'ananuma'

Family: No family assigned Transmission/ Vectors: Virus is transmitted by a vector. Virus is transmitted by mechanical inoculation; transmitted by grafting; not transmitted by contact between hosts; transmitted by seeds (up to 40% in Viola arvensis or only to 1% in Capsella bursa-pastoris). Vector Transmission: Virus is transmitted by nematodes; family Trichodoridae; Paratrichodorus allius, P. anemones, P. christiei, P. nanus, P. pachydermus, P. teres, Trichodorus minor, T. primitivus, T. viruliferus. Anterior of Paratrichodorus minor a vector of Tobacco rattle virus

Family: No family assigned Diagnostic viral inclusions: Inclusions of Tobacco rattle virus in subveinal epidermal cells of an inoculated leaf (Nicotiana tabaccum) stained with Azure A. (Pictures taken from "Light and Electron Microscopy of Plant Virus Inclusions" by R. G. Christie and J. R. Edwardson)

Nepovirus-Tobacco ringspot virus (TRSV)
Family: Comoviridae Description: Virions consist of a capsid. Virus capsid is not enveloped, round with icosahedral symmetry. The isometric capsid has a diameter of nm (virions may swell at pH 8.0). Capsids appear hexagonal in outline. The capsomer arrangement is not obvious.

Family: Comoviridae Hosts: Cucumis sativus, Glycine max, Lycopersicon esculentum, Nicotiana tabacum — necrotic spots, mottling, chlorotic ringspots and vein banding. Virginia Tech Learning Resources Center, Virginia Polytechnic Institute and State University, Bugwood.org Tobacco ringspot virus symptoms on tobacco Virginia Tech Learning Resources Center, Virginia Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org Tobacco ringspot virus symptoms on bean

Family: Comoviridae Vector: Trichodorus ssp., a nematode vector of Tobacco ringspot virus. Anterior view of Trichodorus ssp. nematode

Family: Comoviridae Diagnostic viral inclusions: Vacuolate - Vesiculate Virus crystals & aggregates Xylem blockage Uneven distribution Glandular hair cells Guard cells Phloem Sub-veinal Irregular vacuolate Irregular non-vacuolate Crystalloid Microcrystal UF IFAS Extension Plant Disease Clinic UF IFAS Extension Plant Disease Clinic Nicotiana benthamiana 1000X

Crinivirus-Tomato infectious chlorosis virus (TICV)
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 nm and a width of 12 nm.

Family: Closteroviridae Hosts: Lycopersicon esculentum — interveinal yellowing, necrosis and severe yield loss. tomato, (Lycopersicon esculentum), tomatillo (Physalis ixocarpa), potato (Solanum tuberosum), artichoke (Cynara scolymus), lettuce (Lactuca sativa) and petunia (Petunia hybrida). Vector: Trialeurodes vaporariorum transmission by Bemisia spp. Is uncertain W. M. Wintermantel, USDA-ARS, Salinas, CA, USA. W. M. Wintermantel, USDA-ARS, Salinas, CA, USA. Tomato plant infected with Tomato infectious chlorosis virus showing interveinal chlorosis and mild necrosis on leaflet Tomato plant infected with Tomato infectious chlorosis virus showing interveinal chlorosis and mild necrosis on leaflet

Family: Closteroviridae Diagnostic viral inclusions: All cytoplasmic Paracrystals Banded bodies Densely stained phloem with many vacuoles.

Tospovirus-Tomato spotted wilt virus (TSWV)
Family: Bunyaviridae Description: Virions consist of an envelope and a nucleocapsid. Virus capsid is enveloped. Virions are spherical to pleomorphic measuring nm in diameter. The envelope surrounds three nucleocapsids. Surface projections are distinctive spikes that are surrounded by a prominent fringe. Surface projections are embedded in a lipid bilayer that is 5 nm thick. Surface projections are 5-10 nm long. Capsid/nucleocapsid is elongated and exhibits helical symmetry. The ribonucleocapsid is filamentous with a length of nm (depending on arrangement) and a width of nm. Nucleocapsids are circular. IACR Rothamsted Tomato spotted wilt virus

Family: Bunyaviridae Hosts: Ananas comosus, Bidens pilosa, Capsicum annuum, Datura stramonium, Helianthus annuus, Ipomoea congesta, Lactuca sativa, Malva parviflora, Nicandra physalodes, Phaseolus vulgaris, Physalis peruviana, Zinnia elegans, Arachis hypogaea, Canavalia gladiata, C. obtusifolia, C. occidentalis, Crotalaria juncea, Desmodium triflorum, Glycine max, Pisum sativum, Tephrosia purpurea, Vicia faba, Vigna mungo, V. radiata, V. unguiculata, Lycopersicon esculentum, Nicotiana tabacum, Solanum melongena, S. capsicastrum, S. tuberosum and many other species Jeffrey W. Lotz, Florida Department of Agriculture and Consumer Services, Bugwood.org Florida Division of Plant Industry Archive, Florida Department of Agriculture and Consumer Services, Bugwood.org

Family: Bunyaviridae Symptoms: necrotic and chlorotic local lesions, systemic wilting, necrosis, spotting, streaking, mosaic, mottling, leaf shape malformation, vein yellowing, ringspots, line patterns, yellow netting and flower colour-breaking. David B. Langston, University of Georgia, Bugwood.org Tomato spotted wilt symptoms on pepper leaves David B. Langston, University of Georgia, Bugwood.org Tomato spotted wilt symptoms on pepper

Family: Bunyaviridae Vector: Nine species are reported as vectors: Frankliniella occidentalis (western flower thrips); F schultzei, F fusca (tobacco thrips); Thrips tabaci (onion thrips); T setosus, T moultoni; F tenuicornis, Lithothrips dorsalis, and Scirtothrips dorsalis. The first four are considered the most important vectors because of their wide distribution and the overlapping host ranges of these species and TSWV. J.P. Sanderson, Cornell University, Ithaca, NY Western flower thrips larvae, Frankliniella occidentalis Lyle Buss, University of Florida Tobacco thrips, Frankliniella fusca

Family: Bunyaviridae Diagnostic viral inclusions: Vacuolate Dense, Irregular with projections Crystalline UF IFAS Extension Plant Disease Clinic Tomato spotted wilt virus inclusions UF IFAS Extension Plant Disease Clinic

Begomovirus-Tomato yellow leaf curl virus (TSWV)
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 20 nm. Capsids appear hexagonal in outline. The capsomer arrangement is not obvious. With a length of dimers 30 nm.

Family: Geminiviridae Hosts: • In tomato, symptoms are more severe when infected at an earlier age and vary somewhat among the different cultivars. • In tomato, upward curling of leaves; mottling and often chlorotic leaf margins. • In tomato, leaves are reduced in size. • In tomato, plants are stunted. • Flower abscission in tomato resulting in greatly reduced fruit set. • No symptoms are observed in pepper. Don Ferrin, Louisiana State Univ. Agric. Ctr. Bugwood.org Florida Department of Agriculture and Consumer Svcs, Bugwood.org

Family: Geminiviridae Vector: Virus is transmitted by immature and adult white flies, Bemesia tabaci. Virus is transmitted by mechanical inoculation (poorly, transmitted by grafting; not transmitted by contact between hosts). Don Ferrin, Louisiana State Univ. Agric. Ctr. Bugwood.org

Family: Geminiviridae Diagnostic viral inclusion: Nuclear Rounded dense bodies Ring-shaped (rare) Brittle crystals Florida Department of Agriculture and Consumer Svcs, Bugwood.org UF IFAS Extension Plant Disease Clinic UF IFAS Extension Plant Disease Clinic

Potyvirus-Watermelon mosaic virus (WMV-2)
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 length of nm. Axial canal is indistinct. Basic helix is obscure. Purcifull & Batchelor, Bull. Fla agric. Exp. Stn, 1977 Flexuous particles in leaf extract, negatively stained with potassium phosphotungstate.

Family: Potyviridae Hosts: Cucurbita pepo, Cucumis melo, C. sativus, Citrullus lanatus and some legumes — mosaic, mottling, leaf shape malformation. Persistent symptoms. Both Photographs by: Texas A&M Extension Service

Family: Potyviridae Vector: Virus is transmitted by insects of the order Hemiptera, family Aphididae; Myzus persicae, Aphis craccivora, Aphis citricola, Aphis gossypii; at least 38 species of aphid in 19 genera transmit watermelon mosaic virus 2. Lyle Buss, Univ. of Florida Green peach aphid, Myzus persicae Lyle Buss, Univ. of Florida Cotton/Melon aphid, Aphis gossypii

Family: Potyviridae Viral diagnostic inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections Inclusion of WMV in pumpkin epidermal cells (image courtesty of R.Cullen and M Gooch) Inclusions of WMV in pumpkin (C.A. Baker)

Potyvirus-Zucchini yellow mosaic virus (ZYMV)
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 and a width of 11 nm. Axial canal is indistinct. Basic helix is obscure. V. Lisa Istituto di Fitovirologia applicata del C.N.R., Torino, Italy H. Lecoq Station de Pathologie Vegetale INRA, Montfavet, France Purified Zucchini yellow mosiac virus particles in uranyl acetate.

Leaf deformation, shoe-stringing and mosaic in naturally infected zucchini squash. Potyvirus-Zucchini yellow mosaic virus (ZYMV) Family: Potyviridae Hosts: zucchini squash (Cucurbita pepo), muskmelon (Cucumis melo), cucumber (Cucumis sativus) and watermelon (Citrullus lanatus). Vector: transmitted in non-persistent manner by Aphis citricola , A. gossypii, Myzus persicae and Macrosiphum euphorbiae . Fruit deformation in field-raised /infected zucchini squash after infection by ZYMV ..

Family: Potyviridae Hosts: zucchini squash (Cucurbita pepo), muskmelon (Cucumis melo), cucumber (Cucumis sativus) and watermelon (Citrullus lanatus). Vector: transmitted in non-persistent manner by Aphis citricola , A. gossypii, Myzus persicae and Macrosiphum euphorbiae .

Family: Potyviridae Viral diagnostic inclusions: Cytoplasmic cylindirical 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 Most crystalline Cytoplasmic microbodies Healthy cells Proteinaceous crystals increase in number & aggregate with some Potyvirus infections Florida Department of Agriculture and Consumer Svcs. Epidermal leaf strip of squash infected with ZYMV stained in OG. (I=cylindrical inclusions, N=nucleus)

Virus and Viroid Plant Pathogens

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