Virus Diseases of Trees and Shrubs

Home , Apple mosaic virus, Arabis mosaic virus, Carlavirus, Cherry leaf roll virus, Cucumovirus, Cuscuta

VirusDiseases of Treesand Shrubs

Instituteof TerrestrialEcology NaturalEnvironment Research Council á Natural Environment Research Council Institute of Terrestrial Ecology

J.1. Cooper

Institute of Terrestrial Ecology

Published in 1979 by Institute of Terrestrial Ecology 68 Hills Road Cambridge CB2 ILA ISBN 0-904282-28-7

The Institute of Terrestrial Ecology (ITE) was established in 1973, from the former Nature Conservancy's research stations and staff, joined later by the Institute of Tree Biology and the Culture Centre of Algae and Protozoa. ITE contributes to and draws upon the collective knowledge of the fourteen sister institutes \Which make up the Natural Environment Research Council, spanning all the environmental sciences.

The Institute studies the factors determining the structure, composition and processes of land and freshwater systems, and of individual plant and animal species. It is developing a sounder scientific basis for predicting and modelling environmental trends arising from natural or man- made change. The results of this research are available to those responsible for the protection, management and wise use of our natural resources.

Nearly half of ITE's work is research commissioned by customers, such as the Nature Con- servancy Council who require information for wildlife conservation, the Forestry Commission and the Department of the Environment. The remainder is fundamental research supported by NERC. ITE's expertise is widely used by international organisations in overseas projects and programmes of research.

The photograph on the front cover is of Red Flowering Horse Chestnut (Aesculus carnea Hayne). The branch on the left is healthy whereas that at the right has leaves with a yellow mosaic symptom associated with an ilar virus ressembling apple mosaic. Reproduced by kind permission of Long Ashton Research Station.

Author's address Institute of Terrestrial Ecology c/o Unit of Invertebrate Virology 5 South Parks Road OXFORD OX1 3UB Contents

Illustrations

All Colour Photographs have been brought together in one central spread. The black and white photographs are distributed at the relevant places throughout the text. á To Audrey, Wendy and Elaine á VIRUS DISEASES OF TREES AND SHRUBS

Introduction

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EJL:13,±C. 73'1 ',edr-S. c..erse tr.ssu ir,ses Pesause see, crnE)7,_; ssca res,st .Hruses offesono trees ssd s- r P, ,,ss.0ses tne surlsssi ns„ maTeria ssse rsov-...e,er, man; virsses are known to Pe seed-u-ans- During ine last t, sears, 0ruses "stled. tno..sgsi transmission is usca.i,s Arequent. recogn:zed as na»sr threats )0 agr su;-,,ra. and rsyti - However, seed transmission ot some v.ruses threates cultural crops Tney affect plants n the product.on of woody nursery str.30: pronus necrotic times tney cause obv,os .,ar0t ringspot s.rus w;despread in tne seed bf Prunus spp occasionaHy !nc,ting abnorssa.deveisoment sf °ranches (up to although subsequent mfection difficwt and stems, for example, potato mop t,3.0 (Hate 1, to detect by vssuarly inspecting foliage (Cjmer, 1955). In other instances, losses of ,,ig0ur. :Held and competi- Tne presence of tnis virus is somet:mes shown oy graft tive ability occur Jn the absence of obvious blemisnes incompatibilities (a crown zosie and pitting of wood at Potato \druses were among the first to be recsignized the union) developing when ussig infected but because 'degenerat.on' (yielc-1 decline), attributab;e symptomiess root-stocks (Plate 2) viruses, increased in prevalence with the use of seed tubers from successive diseased crops Johnson (1925) observed tnat apparently healthy potatoes could be See Hate 2a and b (Colour) symptomless carriers potentially jeopardizing adjacent plants. Interestingly, many virus-infected trees show The spread uf most viruses rs dependent upon a variety symptoms for only a few weeks in a 'year and often onli of agencies, including man whp has increased tneir part of the foltage is affected In man / instances viruses occurrence by n;s predilection for vegetative propaga- have been isolated from superficially healthy trees tion. Viruses are widespread in the plant kingdom, and snrubs. having been recorded in non-flowering (algae, fungi, mosses and ferns) as well as flowering plants. Viruses affecting non-woody flowering plants have already been adequateiy considered in text books and reviews, but those affecting woody prennials have been neglec- ted. Numerous fragmentary records ex:st, but they have rarely been collated, excepting those dealing with fruit trees, e g. Malus (Posnette and Cropley, 1963) and Prunus (Anon, 1976). Martin (1925), Peace (1962) and Hepting (1971), while concentrating on bacterial and fungal diseases, gave scant attent:on tne reported occurrence of virus-like diseases. To some extent, these deficiencies were corrected (Bnerley, 1944; Seliskar, 1966; Schmeizer, 1968), but the recent 'flood' of published observations suggested the need to reappraise the situation. Because trees probably react in the same way as other woody perennials, :t was decHed to extend this review to include viruses and virus-like diseases of trees and shrubs, the range of hosts being restricted to those hardy in the UK. To avoid repeating the review collated by Frazier and others 7—Pi:itdto mop-tun in naturally infected nritatn (eV Wind Ha.-..K) the virus caused one stem (at right) tr, be ve'i (1970), it was decided to omit viruses and virus-like 5 t d'IL,ther frum Ire sdrrie tuber develuoeJ r“), manl,/ diseases of orchard crops, excepting those also grown for amenity. Together, these limits exclude descriptions

7 P/ate 0000 swollen shoot left roots and at right, branches 7- aroma cacao. L. naturally infected with the virus. •

of some of the welJ -documented conditions of tropical virologists, and not necessarily the importance of either trees—swollen shoot/mottle leaf of cocoa (Theobroma viruses or hosts. cacao L.) (Plate 3), spike disease of sandalwood (Santalum album L ). lethal yellowing of coconut Virus names (Cocos nucifera L ) (Maramorosch et at 1970 , Hull, Plant viruses have often been given names that describe 1971 ; Dirkstra and Lee, 1972 ; Brunt and Kenten, 1971 symptoms found in the first of their hosts to be identified Grylls and Hunt, 1971). In consider ing the descriptions (see Martyn, 1968 and 1971) Thus, it is now known of viruses and virus-like diseases given in this work, that cherry leaf roll virus (CLRV), which was first the reader should be aware that the amount of detail characterized when shown to cause the upward rolling largely reflects the numbers and location of trained of bronzed leaves of cherry (Prunusavium L.) (Plate 4), -'90.11111111P6 S Jr, 1041 , -1 00 \ 4Ika4 a 6 •

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Plate 4—Prunus aviurn Fl 2/1 showing (at left) leaf rolling premature aekliation and terminal drenack in the year following mechanical inoculation witn an isolate of cherry leaf roll virus from taron. At right, healthy plant of the same clone fur comparison.

8 eao ear er ceen assge ated a o sease ATer can e iLei77tiS arrercana). and subseg6enro •.o:th .eaf e.der Sa.77.7,u.crs ane co and .ee pareerg s ,er been 3erv.e biesgja L s,'n /err:AT:5.aErin ) a-d (J.Fgeas reg,a L oses ea.e 5D—C crecerees fl ConT—L—. 3,71 ros-coo._ .eo deat, !neeres s) cf 5 a-- ceen ..oed aut6r—b.> ee. a ng ener.' of secencar; e.,acefs :cassfI rnene Otner procerbes t,:‹e has': range, are !baiter:a or fungi) teernseIves cads.ng .dent fyimg and g.sfue.g_: sn.6g s.dry.fcaet --./Dre •genera' zed decay aed ucera: De. ciferent •groubs cf viruses Frarr,sian er al., 1971. i. caeners) Fenner. 1976). dr, unnatural ,ncrease in cell number (byperp:as:a) (PIate 6) and/or cell size (hypertrophy) may produce a tumour Viruses and the diseases they cause capable of erupting through bark and Aitnough some viruses kill cells and, in rare instances, 'much, r] turn, may be colonized by whole plants, the effects (symptoms) are usually less organisms causing secondary cankers. drastic (Corbett and Srsler, 1964 Bos, 1970; Smith, 1972) Symptoms vary, responding to changing en- (iii) local under-production of cells (hypo- vironmental concitions. to differing isolates of the same plasia) and/or cessation of cell division virus, and other factors. (atrophy) may produce pits and grooves with affected stems appearing to be (a) Foliage symptoms flattened. When a flap of bark is raised, The colour of virus-infected foliage is typically depressions in wood tissues are some- yellow or pale-green (chlorotic) in part or com- times found to be matched by protrusions pletely. and sometimes red. The colour change from the inner surface of bark. may be distributed more or less evenly within a leaf, or be restricted to: (i) veins General properties of viruses (ii) localized patches (mottling mosaics) Virus particles are composed of two parts, a nucleic acid (in) lines or rings core and a proteinaceous coat. Although some plant viruses have complex shapes, most are either tubular In a few instances, viruses affect leaf shape and, on or spherical. Many are carried from one host to another rare occasions, wilting is a consequence of infec- by specific vectors, such as insects. Some are carried tion. In other instances, virus infections stimulate in pollen and transferred to seeds and seedlings. the development of outgrowths (enations) (Plate Commercial vegetative propagation is an important 5), often from lower leaf surfaces and commonly means of dissemination in cultivated woody plants. near veins, where they may be mistaken for insect Because viruses infect all host tissues and can migrate galls. Virus infections of trees and shrubs are also across graft unions, healthy scions soon become infec- associated with changes in branch colour, but, for ted when grafted to a diseased rootstock and vice versa. part of the year, these are masked by foliage. Mechanisms of natural dispersal Viruses can be naturally dispersed by :— (a) parasitic animals, such as arthropods. nematodes, arachnids (b) parasitic plants. such as root-infecting fungi, dodder (Cuscuta sop. Plate 7) (c) seed (d) pollen (e) grafting (f) contact (g) vegetative propagation

Plant cell walls and cuticles are impermeable to viruses and, as a result. the walls must be damaged (punctured), for example by arthropod feeding, before the virus particles, that the vectors carry, can contact cell proto- plasm. This process is obviated by those viruses that infect pollen and seeds. In general, a virus having

Plate 5—cherry (cv Bing) leaves experimentally infected with vectors in one major taxonomic group will not be raspberry nnospot and prune dwarf viruses and showing enations transmitted by organisms of another group. Some 400 and distortion of the laminae. insects are known to transmit about 250 different viruses; the peach potato aphid (Myzus persicae Sulz.),

9 •

Hate 6— Po00,100x OW00170/10eilL1 cv Fa1 brun e .n:Jd to s v hyperplasia of extra combial tissue causing swellings. The cause of this c0ndition is unknutvn but the SWellrega evelerra v0,4ressively and systemically ; bacteria and fungi have not been associated.

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Place 7—Dodder (CLISCito o urii.neai a p ee04 pl int us!en to yansmit viruses experimentally. The fine stems of tne parasite have en0itici 'and ;hoe e7t,;'lisi00.10 e0t0 the vre vituses (e tobraviruses and CuallalajearlIneal inlect ;Ind cau0, syrrul, n0 10 nrod:ien Manc Lireis seem a be c0—ied passivel> ni the parasite vinen it bridges a hedlthy and a vrelsaLfeatall 0cst

10 transmitting about seventy viruses, is probably the most Aphis cracivora Koch on Cupressus funebris Endl. important in temperate regions of the world. Aphid (Eastop, 1958). vectors of non-persistent viruses generally belong to species that produce migrant winged forms (alatae) The first plant virus (rice dwarf) shown to be insect- which disperse the insects to, or from, primary and transmitted had a leaf hopper vector (Fukushi, 1969). secondary hosts. The migrants tend to fly in short hops, These insects are second only to aphids in their landing periodically to feed by probing. plant tissues. importance, transmitting not only viruses (mostly in the Viruses transmitted by aphids (Arthropoda ; Aphi- persistent manner) but also mycoplasma and rickettsia- doidae) are conveniently grouped into :— like organisms, e.g. those consistently associated with sandal spike. Vector leaf hoppers include Chermoidea, (I) Non-persistent viruses: efficiently acquired from, Cicadelloidea, Fulgoroidea (plant hoppers), Membra- and inoculated to, hosts during probes of 30 coidae (tree hoppers) and Jassoidea. Leaf hopper- transmitted viruses commonly multiply in their vectors seconds duration. Their ability to transmit is typically lost within minutes. and, possibly because they need to be inoculated (Hopkins, 1977 ; Hull, 1971 ; Maramorosch, et al, 1970: Maramorosch, 1974) directly to internal food-conduc- (ii) Semi-persistent viruses: an ill-defined group, ting plant tissue, are not usually mechanically trans- probably best considered as having anomalous non-persistent relationships with their vectors, missible. i.e. having the ability to be retained for two or Although aphids and leaf hoppers are of over-riding three hours. importance in temperate regions of the world, other insects may be more important virus vectors elsewhere, (iii) Persistent viruses: require minimum periods of e.g. white flies (Aleyrodoidea), the vectors of the acquisition feeding. Twelve hours or more must Abutilon mosaic infectious agent in hot countries. usually elapse before vectors can transmit an Relatively little is know about white fly-transmitted acquired virus and then only after inoculation agents. In contrast, Chrysomelid beetle-transmitted feeding periods of at least one hour. Typically viruses (tymoviruses), which reach large concentrations persistent viruses are transmitted by a very few in some plants, have been intensively studied—the aphid species ; they are retained when insects isolation of a tymovirus is mentioned later when des- moult and, in some instances, are transmitted to cribing a virus-like condition in Abelia. Although young via eggs. chrysomelids retain the ability to transmit tymoviruses Although the only well-characterized viruses yet for about a week, the viruses are not known to multiply detected in conifers have soil-inhabiting vectors, others in their vectors. Other groups of insects including mealy with aerial vectors will doubtless be found. Three bugs (Coccoidea), the vectors of cocoa swollen shoot polyphagous aphid species capable of transmitting virus, leaf miner flies (Lirimyza langei Frick) (Costa et al, numerous viruses (Kennedy et al, 1962) have been 1958), and, exceptionally, grasshoppers (Walters, recorded on conifers : Aphis fabae Scop, feeds and 1952), some butterfly and moth larvae, can transmit reproduces on species of Larix, Picea, Tsuga and Pinus viruses, as can eriophyid mites (Arachnida ; Aracina). Aulocorthum circumflexum (Buckton) on seedlings of Mites transmit viruses but feeding itself sometimes Picea sitchensis Carr. (Carter and Eastop, 1973) ; and induces damage (see Carter, 1973 ; Matthews, 1970).

Plate 8—The size range of arthropod vectors of plant viruses illustrated with four examples (left to right) : Leaf hoppers (Nephatettix sp., length c. 5mm) ; Beetle (Oulema melanopa, length c. 4mm) ; Aphid (Aphis fabae): at a greater magnification Eriophyid mite (Vasetes rulioae, length c. 0.2mm) Photograph by courtesy& Natural Environment Research CoUncil 11 T

ktersueri aeria. sosberse,...: vess P a:e of ttga.thv re_en s H ate 10) ioth d ses:ed woric-svco moor-lance, the tflree knil.",,,n types plants tracsse:S.:,isn are not uesmprsinae`. escee, Focally i— Serology Plant v]ruses introduced isLo d'H-nas CtO, O s ast•dees. These provoke immone responses siss-i,claidss after a (a) transmrss:on to abraded roots of stable viruses latent period 6; tne aboearance of ant.oscies in b;ood surviving in plant debos (Smith el al.1969). and other body Ibbds. Because ant bod.es are Isigi4 (b) transmission by vagrant soil-living nematodes specific and can be uses: fsr us v tr() assa.is (Ptsoe. 11 a (c) transmission by sod fungi. and Rate 11b. colour). seressoica tests bro .,;de ;slant virologists with rapid means of unambiguCusT; identi- Because of their longevity. woody perennials are vulner- fying viruses (Gibbs and Harrison, 1976 ; Mattnevys. able to infection for protracted periods. Very few of the 1957 ; Wetter, 1965; Ball, 1974) many pests and pathogens that colonizer sometimes transitorily, trees and shrubs have been tested for their Groups of viruses infecting woody perennials abilities to spread viruses. Even if most of them were About twelve of the 22 established groups of higher inefficient, the feeding damage done to plant cell walls plant viruses have been detected ,n trees and shrubs might allow incidental transmission of viruses. For ex- (Plate 12). Until now, the commonest ate tH7se with ample, it was found that aphids can inoculate plants spherical particles. 30 nm in diameter. and with w,de with viruses when clawing (scratching) leaf surfaces (Bradley and Harris. 1972). Filamentous fungi which develop mycorrhizal associations with roots of trees and shrubs remain untested, yet seem well placed to act as agents of virus spread. Srmilarly. mistletoe (Viscum sop.) and root parasites such as Orobanche spp. are untested, but are possble vectors of viruses affecting trees. Dodders (Cuscora spp ) are a group of parasitic flowering plants first shown in 1940 to transmit viruses (Bennett, 1940). and these parasites are now used routinely for transmitting viruses which are not readily .14g, transmitted mechanically. by other vectors or via normal grafts (Plate 9). Although probably much less important as virus vectors than aphids. nematodes, etc.. species such as Cuscuza gronovil Willd. parasibzing trees in tne USA may, in rare instances, introduce viruses into tneir hosts. Even animals with restricted breeding or normal host ranges will probe into a convenient host before deciding whether or not it merits more prolonged attention and may transmit viruses at the same tune. The feeding activities of birds may similarly offer occasional opportunities for incidental virus transmission. Alternatively, viruses may in some instances spread via (tne sit)) I' Hi natural root grafts or leaf contact, and it is possible that virus-carrying pollen may contaminate flowers of other n uslin Nifecn.», ,s plant species. Conceivably, mechanical transmission tin -»rr fl .. SirS rh,o •-orn pluculcm is ge.,:tly ruboed cv,”- occurs naturally when adjacent pollen-coated leaves aft+' rub one against the other. It is commonplace in lab- rninunsrio niP rHk cintdrinnjtin tht. irtnCh oratory tests to transmit viruses by rubbing leaf surfaces

12 1. Nepoviruses have wide host ranges (their soil- inhabiting nematode vectors feed on the roots of AS many different plants) and are opportunists which have been frequently detected in trees and shrubs, 1 2 3 e.g. arabis mosaic in ash (Fraxinus excelsior L.. F. americana L.) and cherry leaf roll virus in birch and walnut. Although their soil-inhabiting Plate 1 la—Diagrammatic representation illustrating the range of nematode vectors are slow moving (30cm/yr), precipitation reactions observable in a commonly used in vitro serological test. S. well containing virus (the antigen. often sap nepoviruses may spread rapidly because they are from infected plants) AS, well containing antiserum. additionally transmitted in pollen and seed. 1. Non-identity. Two precipitin lines cross occuring when two antigen wells contain distinct antigens which react with two 2. Ilarviruses are economically important and wide- different antibodies Present together in the antiserum well (AS). spread in fruit trees, and have been recorded in 2. Identity. Fusion of precipitin lines occuring when the antigens in the two wells combine with the same antibodies. amenity trees, such as elm mottle in lilac (Syringe 3. Partial-identity. Fusion of precipitin lines but with one showing vulgaris L.) and elm (Ulmus glabra L.) ; apple/rose the formation of a spur. Such reactions give rise to speculation mosaic in rose (Rosa spp. generally) ; prunus concerning the degrees of similarity possessed by the two viral necrotic ringspot in horse chestnut (Aesculus antigens. Photograph by courtesy of Natural Environment Research Council hippocastanum L.) ; tulare apple mosaic and apple mosaic viruses in hazel (Corylus avellana L.). Ilarviruses tend to be host specific, being trans- host ranges (the opportunists). Future investigations ferred from host to host via pollen. Other means of are likely to show that ranges of 'specialist viruses, re- transmission are at present unknown. sembling poplar mosaic and robinia true mosaic, and which naturally infect few hosts, are also common in 3. Cucumoviruses infect plants in more than forty woody perennials. plant families. They are among the commonest opportunists found in cultivated plants, such as (a) Viruses with spherical particles cucumber mosaic in honeysuckle (Lonicera peri- 1. Nepoviruses clymenum L.) ; privet (Ligustrum spp.) and 2. Ilarviruses Paulownia tomentosa (Thunb) Steud. Cucumo- 3. Cucumoviruses viruses are transmitted in seed, and. non-persist- 4. Tobacco necrosis viruses ently by at least sixty species of polyphagous aphid vectors. (b) Viruses with rod-shaped particles 5. Tobraviruses 4. Tobacco necrosis virus (TNV) is a group composed 6. Tobamoviruses of many variants, capable of infecting species in 7. Potexviruses at least 37 plant families. Unlike nepo-, ilar-, and 8. Carlavi ruses cucumo-viruses which permeate roots, shoots and 9. Potyviruses foliage. TNV is typically confined to roots, being 10. Closteroviruses transmitted by root-infecting fungi.

(c) Viruses with other shapes (e.g. bacilliform, sausage- 5. Tobraviruses are transmitted by vagrant soil- shaped, particles) inhabiting nematodes (Trichodorus and Para- 11. Alfalfa mosaic trichodorus) to more than 400 species in fifty plant 12. Rhabdoviruses families. Tobraviruses resemble TNV in that they

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Plate 12—Spectrum of shapes and sizes of virus particles detected in trees and shrubs. Photograph by courtesy of Natural Environment Research Council 13 are often restricted to roots. Tobacco rattle virus, 12. Rhabdoviruseshave relatively large bacilliform or the more prevalent member of the group, damages bullet-shaped particles resembling some viruses many agricultural and horticultural crops and has naturally infecting insects and others associated been associated with foliage symptoms in Chino- with diseases of fish and mammals. Some are nanthus virginica L. and was detected in poplar persistently transmitted by aphids or leaf hoppers. roots (Cooper and Sweet, 1976). Of those which infect plants, few have been studied in detail. Rhabdovirus-like particles have 6. Tobamoviruses occur in large concentrations in been found in tissues of woody plants, e.g. infected plants and can be spread by contact laburnums with foliar vein clearing. (when healthy plants rub against infected specimens). Although they infect many hosts when The twelve groups of viruses briefly described account artificially inoculated, the type member of the for about 10 per cent of the known plant pathogenic group (tobacco mosaic virus, TMV) has been viruses. For further information, reference should be infrequently isolated from trees. Virus particles made to the AAB/CMI Descriptions of Plant Viruses resembling TMV, however, were detected in and to other texts (Matthews, 1970 ; Gibbs and Quercus spp. in conditions that suggest that Harrison, 1976 ; Kado and Agrawal, 1972 ; Mara- natural spread might have occurred with the aid of morosch, 1969). the powdery mildew fungus (Sphaerotheca lanestris Harkin). Other possible members of the group, such as potato mop-top virus, are transmitted by Control (Prevention is better than cure) root-infecting fungi (Plasmodiophorales: Spongo- Except for eliminating affected and unthrifty trees, it is spora subterranea Lagerh.) usually impractical to prevent the spread of viruses after planting into 'the field'. Attention is inevitably focused 7. Potexviruses generally spread by contact when on the nursery production of planting stock where healthy plants rub against infected specimens yet critical examination and assessment of vigour can be tend to have restricted natural host ranges. A practised routinely. Nurserymen should be aware that potexvirus is widely distributed in stocks of hyd- viruses may (i) increase production costs because of rangea. the possibly decreased growth of infected stock plants; and (ii) damage subsequent field performance. Nation- ally, attempts are made to control the introduction and 8. Carlavirusesare specialist viruses, infections often spread of viruses by adopting quarantine measures being symptomless. Some members of the group designed to exclude non-indigenous pests and patho- are transmitted non-persistently by aphids, others gens. Exclusion is particularly important for viruses have been (i) associated with diseases in woody because they are difficult to eraClicate even when host plants, such as poplar mosaic, or (ii) recorded as ranges, rates of spread, and types of vector are fully latent, as in American elder (Sambucus cana- understood. Nevertheless, there are many measures densis L.). that arboriculturists can take to diminish the spread of viruses, particularly in hardy stock nurseries. By 9. Potyviruses are specialists, transmitted by aphids minimizing the unnecessary importation of rooted in the non-persistent manner and sometimes plants, the risk of introducing virus-transmitting soil- transferred in seeds. The economically damaging inhabiting pests, such as eelworms, will be lessened, a disease of fruit trees, plum pox, is readily per- measure emphasising the desirability of producing petuated by vegetative propagation which also home-grown planting stocks. Foliar insecticidal sprays favours the perpetuation of Wisteria vein mosaic. can minimise existing populations of insect vectors and retard their build-up, but they may have little effect 10. Closteroviruses have the longest particles yet upon the incidence of virus diseases caused by non- detected in trees and shrubs. They have a semi- persistent viruses because incoming vectors can trans- persistent relationship with their aphid vectors. mit before being killed by insecticidal residues. By Tristeza (sorrow) virus in citrus has destroyed contrast, insecticides diminish infections caused by seven million orange trees in Brazil alone. Apple viruses spread in the persistent manner. stem grooving and the widespread but frequently inconspicuous apple chlorotic leafspot are less Experiments with food crops have shown that the devastating. Closterovirus-like particles have been spread of non-persistent viruses can be lessened by noted in lilac and Crataegusspp. using reflecting 'mulches' (aluminium foil (Plate 13)) to deter aphids from landing (Smith and Webb, 1969), 11. Alfalfa mosaic virusesare opportunists, widespread and by planting within protective barriers of tall- in woody plants such as Daphne spp., Viburnum growing crops which physically impede incoming opulus L.. Caryopteris incanaL., and Philadelphus vectors while they loose their ability to transmit. For spp. They are capable of infecting more than 300 this reason, bananas are grown with coconuts, so species in 47 plant families. Although their decreasing the incidence of banana bunchy-top carried bacilliform particles are morphologically distinc- by the aphid Pentolonia nigro nervosa Coq (Magee, tive, alfalfa mosaic resembles cucumoviruses in 1967). In Britain, rye (Secale cerealeL.) is grown by being transmitted non-persistently by aphids. some nurserymen as a packing material for their plants.

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Plate 73—Experimental use sif a reflictive rnuLn (1 metre Ague striss gf aluminium f•il laminated on kraft paper) to curtail the spread of viruses trarismitted gsn-persigtently by soHos. To achieve maximum aphid repellency, half the ground should be covered with the toil. In this photogrsph the effecliver.essYdas being assessed on a Lawat •srop. .

The tall cereal mioht d:murush rates of non r ,nt obviated by propagating trees in steam-sterilized virus transmission t• !we oruw:ng shrubs. huiticultural

Sod-inhabiting •ectruri can be effect!. rHierl Virus-like symptoms not associated with viruses treating nursery Sbn:11,v5Htli partial steu,lan.,s, 55: 1b Virus-like symptoms sometimes occur in the absence of methyl brom.de anti dichksiuupropane-d;Lhloropr•RuHe. viruses. In IF (?.seinstances, they may be attributed to ,— Although these Substances rnnunize the tranbyySSH'i (1) feeding damage, e g. foliar mosaics and shoot of viruses, it shouId be remembered that inc....stmust oe proliferation associated with the feeding of applied some •eeks before p'anting, in fauli:tate the eripphyid mites (Carter,1973; Kado and Agrawal, dispersal of plant damag:ng (ohytcyuixic) residueTv 1972; Maramorosch, 1969: Pirone et al, 1960) These cherucals do not wact,vate •uuses. Instead, they kill heir vectors and, i nun di:ng, may d;mirush (u) genetL abnormalities and chimeras; populat;ons of beneficial fungi, such as those forming mycorrhizas with tree roots. (iii) nutrient mmbalannes(Wallace, 1961; Hacskyio et al. 1969) and, as recently discovered

Plant nurseries are, for convenient management. (iv) mycoplasma (MLO) and rickettsia (1910)-like typically sited on open-textured soils favouring organisms. infestations with soil-inhabitHig virus-vector nematodes which are also commonly abundant in hedgerow soils. A group of 'yellowsdiseases, typically associated with Trees and shrubs growing in the latter are commonly (i) foliar yellowing virus-infected. It is therefore prudent (a) to leave wide (H) stunted and proliferating axmllary shoots with headlands and (b) to avoid planting recently cleared abnormally erect habits (witches' brooms); hedgerows for at least three years, unless the soil is (hi) conversion of petals to leafy structures (phyllody partially sterilized. Alternatively, these risks can be Plate 14, Colour). was, until 1967, thought to, be caused by viruses (Doi Bennett, C.W. (1940). Acquisition and transmission of viruses by et al, 1967). Although not normally transmissible by dodder (Cuscuta subinclusa). Phytopathology, 30, 2. mechanically inoculating sap, the infectious agents of Bos, L. (1970). Symptoms of virus diseases in plants. Wagen- "yellowsdiseases were transmitted by leaf hoppers, ingen. Centre for agricultural publications and documentation. 2nd Edn. by grafting and some, at least, by dodders (Cuscuta Bradley, R.H.E., and Harris, K.F. (1972). Aphids can inoculate spp.). When ultra-thin sections of affected tissues were plants with tobacco mosaic virus by clawing. Virology, 50, 61 5- examined in electron microscopes, rounded or elong- 18. ated bodies were observed. These bodies, encom- Brierley, P. (1944). Viruses described primarily on ornamental or miscellaneous hosts. passed by unit membranes, seem to contain ribosomes Pl. Dis, Reptr. 150 Suppl. 410-482. Brunt, A.A. and Kenten, R.H. (1971). Viruses infecting cacao. and vary in size (100-1000 nm). Together with helical Rev. Pl. Path. 50, 591-602. spiroplasma bodies, 250 nm wide and up to 12,000 nm long, associated with the 'stubborn' disease of citrus Carter, C.I. and Eastop, V.F. (1973). Mindarus obliquus (Chol.) (Homoptera, Aphidoidea) new to Britain and records of two other (Davis and Worley, 1973 ; Saglio et al, 1973), they are aphids recently found feeding on conifers. Entomologist's mon. classified as mycoplasma-like organisms (ML05). All Mag. 108, 202-4. plant MLOs seem to multiply in their insect vectors. Carter, W. (1973). Insects in relation to plant disease. 2nd Edn Perhaps because high temperatures favour the build-up New York: London. Wiley Interscience. of leaf-hopper populations it is not surprising that Cooper, J.I. and Sweet, J.B. (1976). The detection of viruses diseases of mulberry, walnut, pecan and ash, attributed with nematode vectors in six woody hosts. Forestry 49, 73-8. Corbett, M.K. and Sisler. H.D. (1964). Plant Virology. Gainesville to MLOs are frequently reported when and where University of Florida Press. temperatures are high. While symptoms attributed to Costa, A.S., De Silva, D.M. and Duffus, J.E. (1958). Plant virus viruses are unaffected, symptoms of MLO diseases are transmission by a leaf-miner fly. Virology 5, 145-9. suppressed by tetra- and chlortetra-cycline antibiotics. Davis, R.E. and Worley, J.F. (1973). Sprioplasma : motile, helical microorganisms associated with corn stunt disease. Phytopath- Rickettsia-like organisms (RLOs) which have relatively ology, 63, 403-8. thick outer membranes occur in the water-conducting Dijkstra, J. and Lee, P.E. (1972). Transmission by dodder of sandal spike disease and the accompanying mycoplasma-like channels (xylem vessels) of their plant hosts in contrast organisms via Vinca rosea. Neth. J. Pl. Pathol. 78, 218-224. to MLOs which abound in food conducting phloem. Doi, Y., Teranaka, M., Yora, K. and Asuyama, H. (1967). Myco- Understandably therefore, RLOs tend to be associated plasma-or PLT group-like micro-organisms found in the phloem with symptoms of wilt, particularly in young tissues. elements of plants infected with mulberry dwarf, potato witches' Whereas RLOs are graft transmissible, this method of broom, aster yellows or Paulownia witches' broom. Ann. phytopathol. Soc. Japan 33, 259-66. dissemination is only successful when the source Eastop, V.F. (1958). A study of the Aphididae (Homoptera) of material includes woody tissues. In common with East Africa. Colon. Res. Pubis. 20, pp. 126. M LOs, they have leaf-hopper vectors but, in contrast. Fenner, F. (1976). Classification and nomenclature of viruses. RLOs tolerate tetracycline antibiotics. Characteristic- lntervirology, 7. pp. 115. ally, diseases associated with RLOs are sensitive to Frazier, N.W., Fulton, J.P., Thresh, J.M., Converse, R.H., Varney, E.H. and Hewitt, W.B. (1970). Virus diseases of small fruits and differing penicillins which do not seem to affect either grape vines. Berkeley : University of California, Division of Agri. viruses or MLOs. Sciences. Fukushi, T. (1969). Relationships between propagative rice Classically it was assumed that viruses were the causes viruses and their vectors. Viruses, vectors and vegetation. Ed. K. of disease if infectious agents could not be separated by M aramorosch, 279-301. New York : London. Wiley I nterscience. Gibbs, A. and Harrison, B. (1976). Plant virology: the principles. filtration from extracts of diseased plants. Now, how- London, Edward Arnold. ever, the list must be extended to include both MLOs Gill, L.S. (1935). Arceuthobium in the United States. Trans. and RLOs which are capable of passing through filters Conn. Acad. Arts Sci. 32, 111-245. that retain bacteria. Gill, L.S. and Hawksworth, F.G. (1961). The mistletoes. A literature review. Tech. Bull. U.S. Dept. Agric. no. 1242. Gilmer, R.M. (1955). Imported Mahaleb seeds as carriers of The development of "witches' brooms" in coniferous necrotic ringspot virus. Pl. Dis. Reptr. 39, 727-8. and broadleaved trees-some affected conifers are Grylls, N.E. and Hunt, P. (1971). A review of the study of the retained as commercially desirable dwarf stocks aetiology of coconut lethal yellowing disease. Oleagineaux 26, (Waxman, 1975)-has been associated with a variety 311-315. of pests and pathogens including fungi, insects, mites Hacskylo, J., Finn, R.F. and Vimmerstedt, J.P. (1969). Deficiency symptoms of some forest trees. Res. Bull. Ohio Agric. Res. and, in the USA, dwarf mistletoe (Arceuthobium spp). Developm. Centr. no. 1015. (Gill and Hawksworth, 1961 Gill, 1935; Hawksworth, Harrison, B.D., Finch, J.T., Gibbs, A. J. Hollings, M., Shepherd, 1961 ; Hawksworth and Hines, 1964). However, in R.J., Velenta, V. and Watter, C. (1971). Sixteen groups of plant some instances, pests and pathogens do not seem to be viruses. Virology 45, 356-363. involved. Hawksworth, F.G. (1961). Dwarf mistletoe of ponderosa pine in the Southwest. Tech. Bull. U.S. Dept. Agric. no. 1246. Hawksworth, F.G. and Hines, T.E. (1964). Effects of dwarf mistletoe on immature lodge-pole pine stands in Colorado. J. References For. 62, 27-32. Anon. (1976). Virus diseases and noninfectious disorders of Hepting, G.H. (1971). Diseases of forest and shade trees of the stone fruits in North America. U.S., Dept. Agr., Agric. Handb. United States. U.S. Dept. Agric. Agric. Handb. no. 386. no. 437. Hopkins, D.L. (1977). Diseases caused by leafhopper-borne Ball, E.M. (1974). Serological tests for the identification of plant rickettsia-like bacteria. Ann. Rev. Phytopathol. 17. 277-294. viruses. St. Paul. Minnesota, The American Phytopathological Hull, R. (1971). Mycloplasma-like organisms in plants. Rev. Society Inc. 31pp. Pl. Path, 50, 121-130.

16 Johnson, J. (1925). The transmission of viruses from apparently Posnette, A.F. and Cropley. R. (1963). Virus diseases of apples healthy potatoes. Bulletin Wis. Agric. Exp. Stn. 63. 12 pp. and pear. Tech. Commun. Commonwealth Bur. Hon. Plantn. Kado. Ci. and Agrawal, H.O.. Eds. (1972). Principles and tech- Crops. no 30. niques in plant virology. New York. Van Nostrand Reinhold. Saglio, P.. L'Hospital. M., Lafleche, D., Dupont. G.. Bove. J. M., Kennedy, J.S.. Day, M.F. and Eastop, V.F. (1962). A conspectus Tully, J.G. and Freundt. E.A. (1973). Spiroplasma citri gen. and of aphids as vectors of plant viruses, London. Commonwealth sp. n : a Mycoplasma-like organism associated with "stubborn Institute of Entomology. pp. 114. disease of citrus". Int. J. Syst. Bacteriol. 23, 191-204. Magee, C.J. (1967). The control of banana bunchy top. Tech. Schmelzer. K. (1968). Zier-, Forst- und Wildgeholze. In : Pap. S. Pacif. Comm. no. 150,1-13. Pflanzliche Virologie, edited by M. Klinkowski. vol. 2. Part 2,232- Maramorosch, K.. Ed. (1969). Viruses, vectors and vegetation. 303. Berlin, Akademie - Verlag. New York: Wiley Interscience. Seliskar. C.E. (1966). FAO/IUFRO Symposium on internationally Maramorosch, K. (1974). Mycoplasmas and rickettsiae in re- dangerous forest diseases and insects 44. Oxford 1964. FAO/ lation to plant diseases. Ann. Rev. Microbiol. 28. 301-324. FORPEST, 64-5,1966. Maramorosch, K.. Grandados, R.R. and Hirumi, H. (1970). Smith, K.M. (1972). A textbook of Plant Viruses Diseases. Mycoplasma diseases on plants and insects. Adv. Virus Res. 16, Edinburgh, Longman. 3rd Edn. 135-193. Smith, F.F. and Webb, R.E. (1969). Repelling aphids by reflecting Martin, G.H. (1925). Diseases of forest and shade trees, orna- surfaces a new approach to the control of insect-transmitted mental and miscellaneous plants in the United States in 1924. viruses. In : Viruses, vectors and vegetation, edited by K. Mara- Pl. Dis. Reptr. Suppl. 42, 313-380. morosch, 631-39. New York : London : Wiley Interscience. Martyn, E.B., Ed. (1968). Plant virus names. Phytopathological Smith, P.R., Campbell, R.N. and Fry, P.R. (1969). Root discharge Papers, No. 9. Kew : Commonwealth Mycological Institute. and soil survival of viruses. Phytopathology 59, 1678-1678. Martyn, E.B.. Ed. (1971). Plant virus names. Phytopathological Wallace, T. (1961). The diagnosis of mineral deficiencies in Papers, No. 9, Suppl. 1. Kew: Commonwealth Mycological plants by visual symptoms. 3rd edition. London : HMSO. Institute. Walters, H.J. (1952). Some relationships of three plant viruses to Matthews, R.E.F. (1957). Plant virus serology. Cambridge the differential grasshopper. Melanoplus differentialis. Thos. University Press. Phytopathology 42. 355-62. Mathews, R.E.F. (1970). Plant Virology. New York : London : Waxman, S. (1975). Witches brooms sources of new and inter- Academic Press. esting dwarf forms of Picea, Pinus and Tsuga species. Acta Peace, T.R. (1962). Pathology of trees and shrubs. Oxford : Hortic. 54. 25-32. Clarendon Press. Wetter, C. (1965). Serology in virus-disease diagnosis. Ann. Pirone, P.P., Dode, B.O. and Rickett, H.W. (1960). Diseases Rev. Phytopathol. 3, 19-42. and pests of ornamental plants. New York. Ronald Press.

17 Table 1. Viruses and graft-transmitted conditions recorded from trees and shrubs

18 Symbols in parentheses indicate viruses to which the host was rn tobacco necrosis (Kassanis, 1970; C.M.I./A.A.B. Descr susceptible by inoculation_ Plant Viruses no. 14) n elderberry latent (Jones, 1974 ; C.M.I./A.A.B. Descr. Plant Symbols marked with an asterisk indicate viruses detected in roots Viruses no. 127) but not foliage. o raspberry ringspot (Murant. 1970 C.M.I./A.A.B. Descr. Plant Viruses no. 6) a bean yellow mosaic (Bos. 1970; C.M.I./A.A.B. Descr. Plant p elm mottle (Jones, 1974 : C.M.I./A.A.B. Descr. Plant Viruses Viruses no. 40) no. 139) b arabis mosaic (Murant. 1970 ; C.M.I./A.A.B. Descr. Plant q hydrangea ringspot (Koenig, 1973 : C.M.I./A.A.B. Descr. Viruses no. 16) Plant Viruses no. 114) tobacco ringspot (Stace-Smith. 1970 : C.M.I./A.A.B. Descr. prunus necrotic ringspot (Fulton. 1970 C.M.I./A.A.B. Descr. Plant Viruses no. 17) Plant Viruses no. 5) strawberry latent ringspot (Murant, 1974 ; C.M.I./A.A.B. s tomato bushy stunt (Martelli et al.. 1971 ; C.M.I./A.A.B. Descr. Plant Viruses no. 126) Descr. Plant Viruses no. 69) cucumber mosaic (Gibbs and Harrison. 1970 ; C.M.I./A.A.B. passion fruit woodiness (Taylor and Greber. 1973; C.M.I./ Descr. Plant Viruses no. 1) A.A.B. Descr. Plant Viruses no. 122) f apple mosaic (Fulton, 1972 C.M.I./A.A.B Descr. Plant u poplar mosaic (Biddle and Tinsley. 1971 : C.M.I./A.A.B. Viruses no. 83) Descr. Plant Viruses no. 75) cherry leaf roll (Cropley and Tomlinson, 1971. C.M.I./A.A.B. tobacco streak (Fulton, 1971 ; C.M.I./A.A.B. Descr. Plant Descr. Plant Viruses no. 80) Viruses no. 44) h tobacco rattle (Harrison, 1970 ; C.M.I./A.A.B. Descr. Plant w robina true mosaic (Schmelzer, 1971 ; C.M.I./A.A.B. Descr. Viruses no. 12) Plant Viruses no. 65) alfalfa mosaic (Bos and Jaspers, 1971 C.M.I./A A.B. Descr x tulare apple mosaic (Fulton, 1971 : C.M.I./A.A.B. Descr. Plant Viruses no. 46) Plant Viruses no. 42) tomato black ring (Murant, 1970 ; C.M.I./A A.B. Descr y mulberry ringspot (Tsuchizak, 1975; C.M.I./A.A.B. Descr. Plant Viruses no. 38) Plant Viruses no. 112) k broad bean wilt (Taylor and Stubbs, 1972: C.M.I./A A B. z apple chlorotic leaf spot (Lister, 1970; C.M.I./A.A.B Descr. Descr. Plant Viruses no..81) Plant Viruses no. 30) I tomato ringspot (Stace-Smith, 1970; C.M.I./A.A B. Descr. Plant Viruses no. 18)

Note added in proof

When preparing this conspectus, the author endeavored to be comprehensive but anticipated that some relevant data would be omitted accidentally. He is now aware that in the U.S.A. bean yellow mosaic virus naturally infects Cladrastis lutea Koch and that the virus caused leaf deformation and veinal chlorosis (Provvidenti, R. and Hunter, J.E. Pl. Dis. Reptr. 1975, 59, 86-7).

Furthermore, following the recent presentation to the University of Bristol of a thesis for the degree of Doctor of Philosophy, it is apparent that Dr J. B. Sweet has isolated raspberry ringspot virus from Daphne "Somerset" having in some instances foliar chlorotic spots and has implicated graft transmissible agents resembling apple stem grooving virus (Lister, 1970 C.M.I./A.A.B. Descr. Plant Viruses No. 31) with stunting and chlorotic flecking in leaves of Sorbus "mitchellii".

The author will appreciate being told of any errors of fact or interpretation and would like to be informed of all relevant new data.

19 ABELIA—Caprifoliaceae

_ ss —SSSS z

CF. f:f7:3-3t1 SS. 7 see—e.c. :se .

.55 b a- ,s-; a of Ace a vein cano,ng batTercs e :,•rus "ecte/l dendlon SD withcst caJs ng --,c-mms

Referent&

65. 891-896.

ABELIOPHYLLUM—Oleaceae

Foliage disease

SYMPTOMS : Diffuse mottling along vems in immature leaves with chlorotic patches and later white or red discolourations near veins. Visible only in spring. Fes.re 15--Leaf of Anytion sp. shrywing discrete patches of yellow and shades of green a mossy: symptom associated with a graft- Distribution : In Abehophyllum dIstichum Nakai in tranennss;Ple anent. an East German botanic garden. Transmission I Mechanically by inocula ng infectious sap to -herbaceous hosts.'" Causal agent/Relationship Tomato blackring virus Causal agent/Relationship: Unknown myco- was identified but not proved to be the cause of the plasma-eke organisms were associated in some disease in A. distichum (Schmelzer, 1974). instances with vanegation in A. striatum (de Leeuw, cited in Costa, 1976), Reference Schmelzer. K. (1974). untersuchungen an Yuen der Lien und References Wildegehulze 8. Mittedung Neue Befunde an Forsyrnta. Hydran- gea und Pleladelphus sowie Wen und Virusen an Rharenus. Baur. F. (1904). Zur Atiologie der mfektiosen Panascninrung. Centaurea. Galvezia. Cistus. Forestrera, Abehophyllurn, Celastrns. Ber. ch. bot. Ges. 25. 410-13. costa, A.S. (1976). 07hitafty-ttansmitted plant diseases. Stapnyiea und Crareb& 27n1 Bak!. Parasir Scle 129 Ate' rr. 139 68 Rev. Phytopathol. 14. 429-049. Costa. A.S and Caryahn. A.M.B. (1950). Meohyrdeal myssion and propettyes of the Abunlon mosaic virus. Fly,180 37, 259-72. Flares. E. and Silberschrrady K. (19675 Contribution If ABUTILON—Malvaceae ptoblem of hsest and (net:flatly:al transmisSytn ,f infestryut chlprosis of Malvaseae and the disease disnlyved Sy Ate K./on Foliage disease thornp2one Ph1-Toise7^. 7. 60. I FI-9b Keur (19 341 Study), of thn oy3urty-nse 0f and trassnnssion of virus diseases in he 3enus Anytion. BuIS Fortey [inf. Club 61. SYMPTOMS . Bright yellow-green variegation witches 53-70. broom may occur later (Flores and Silberschmidt.1967). Orlando. A. and Sd9efschro3t, K. (19316). Estudos tbre a Distribution : Probably worldwide in horticulturally semtracao rio sines da CHlorose Infessos37 das Malvacetts (Abnnlon virus I. Baur) B. A. Sda relacao ryftn insen-velnr, desirable and vegetatively propagated Abutilon -Berrosra labefy Genn7. AroSt0s Inst. Be&f. 5 Paulo 17. 1-36. thompsond (A. stnaturn Dickson var Thomsonii Veitch) and A. megapotarnium St. Hilaire and Noral. ACACIA—Leguminosae Transmission : By grafting variegated with healthy Abutilon spp. (Baur, 1904) and in 14-24% seed Acacia sp. (unnamed) were stated (Atanasoff, 1967) (Keur, 1934). In Brazil, natural vectors are white- to be susceptible to natural infection with bean yelfow flies, Bemisia tabaci Genn (Orlando and Siber- mosaic virus but unfortunately the symptoms were not schmidt. 1946). In rare instances mechanical described. so [t- 3 imposstle to judge whether there transmission in sap to "herbaceous hosts- has been was any similanty wIth the yelmw ring-like spots, obtained (Costa and Carvalho, 1960). affecting A. saligna Wendl , which in Italy were report-

20 edly associated with an agent transmissible by grafting Causal agent/Relationship : Unknown; symptoms (Marras, 1962). in test plants resembled those due to tobacco necrosis virus. References Atanasoff, D. (1967). Virus stem pitting of Birch. Z. Pflkrankh. COMMENTS : Mosaic and narrowing of leaf laminae PflPath. PflSchutz, 74, 205-08. in A. negundo Marras, F. (1962). La Maculatura Anulaire dell Acacia saligna. and mild mosaic in A. ginnata Mich. Riv. Patol. Veg., Padova 2, 275-80. developed when these plants were inoculated with tobacco ringspot virus (Wilkinson, 1952).

Arabis mosaic virus was detected in roots of A. pseudoplatanus but was not associated with leaf AC E R-Aceraceae symptoms (Thomas, 1970).

Foliage diseases References Atanasoff, D. (1935). Old and new virus diseases of trees and SYMPTOMS : Yellow mottle-mosaic (Atanasoff, 1935; shrubs. Phytopath. Z. 8, 197-223. Blattny, C. (1950). Poznamka k virove deravosti listu javorovych. for others see Brierley, 1944). Ochr. Rost. 23. 70-71. Distribution : In horticultural forms of Acer negundo Brierley, P. (1944). Viruses described primarily on ornamental or L. and Sycamore (A. pseudoplatanus L.) in Europe miscellaneous hosts. Pl. Dis. Reptr 150 Suppl. 410-482. and Japan. (mimeographed). Kenknight, G. (1960). Prunus injuncunda Small and Acer rublum Transmission : By grafting. L., natural hosts of peach rosette virus. Pl. Dis. Reptr 44. 220. Causal agent/Relationship : Unknown. Ploaie, P. G. and Macovei. A. (1968). New plant virosis recorded in Roumania. Revue. roum. Biol. (Ser. Bot.) 13, 269-274. [For Abstr. 30,4218]. SYMPTOMS : Chlorotic or ring mottle. Smolak, J. (1949). Virove choroby a listy. Ochr. Rost. 22, 173- Distribution : In A. saccharum Marsh in North 203. America (Brierley, 1944) and in Roumania (Ploaie Subikova, V. (1973). The mechanical transmission of Euonymus mosaic virus, maple leaf perforation by leaf extracts or leaf and Macovei, 1968). nucleic acid to herbaceous plants. Biologia Pl. 15. 166-170. Transmission : No information. Szirmai, J. (1972). An Acer virus disease in Maple trees planted in Avenues. Acta phytopathol. Acad. Sci. Hung. 7, 197-207. Causal agent/Relationship : Unknown. Thomas. P.R. (1970). Host status of some plants for Xiphinema diversicaudatum (Micol.) and their susceptibility to viruses SYMPTOMS : Severe stunting and dense green foliage transmitted by this species. Ann. appl. Biol. 65, 169-178. preceding decline and death. Wilkinson, R.E. (1952). Woody plant hosts of the tobacco ringspot virus. Phytopathology 42, 478. Distribution : In A. rubrum L. in USA (Kenknight, 1960). Transmission : By grafting from Acer to rosaceous hosts e.g. Prunus angustifolia Marsh. Causal agent/Relationship : Unknown. A ES C U LUS-Hippocastanaceae

SYMPTOMS : Shortening of internodes, terminal bud See Plate 16 8- 17 .. Colour Et Cover failure, changes in leaf outline and mosaic mottling with chlorotic (tending to yellow ochre) spots (Szirmai, Foliage diseases 1972). SYMPTOMS : Yellow mosaic. Distribution : I n A. negundo and A. pseudoplatanus in Hungary (Szirmai, 1972) and UK (Cooper, un- Distribution : Affecting A. hippocastaneum L. from published data). Czechoslovakia, East Germany, Roumania and UK Transmission : Leaf symptoms are the only part of (Timpi, 1907 cited in Brierley, 1944, Sweet, 1976). the syndrome which have been 'transmitted' (to Propagated commercially and widely distributed eleven of twenty seedlings by chip budding). in UK because of attractive foliage. Whiteflies, Trialeurodes vapoariorum West, were Transmission : By budding and grafting between vectors in two of three tests which have not been A. hippocastaneum, attempted with aphids. also when budded into woody indicators of apple viruses, to cause symptoms Causal agent Relationship : Unknown. resembling those associated with prunus necrotic ring spot virus (Sweet, 1976). No infection de- SYMPTOMS : Vein chlorosis, leaf blade perforation- tected in 50 seedlings from seed of infected A. "tatter leaf" (Smolak, 1949 ; Blattny, 1950). hippocastaneum (Sweet et al, 1978). Distribution : In A. pseudoplatanus and A. negundo Causal agent/Relationship : Unknown ; but sero- in Czechoslovakia. logical tests on yellowed Aesculus leaves revealed Transmission : In sap using charcoal or bentonite infection with the apple mosaic serotype of prunus to aid transmission (Subikova, 1973). necrotic ringspot virus (Sweet et al, 1978).

21 SYMPTOMS : Tatter leaf syndrome called 'necrosis' A R I STO LOC H IA—Aristolochiaceae (Smolak, 1963) associated with diminished growth, clustered branches, few or no flowers and inviable seed. Foliage disease Distribution : In A. hippocastaneum in Czecho- slovakia. SYMPTOMS : Chlorotic ring and line patterns. Transmission : By grafting, even though no union Distribution : Affecting A. durior Hill and A. established. Uncertain whether the whole syn- clematis L. throughout Northern Europe. drome developed in grafted plants. Transmission : Mechanically, by inoculating infec- Causal agent/Relationship : Unknown ; syndrome tious sap to "herbaceous hosts". somewhat resembles incipient witches broom. Causal agent/Relationship : Cucumber mosaic (Lihnell, 1951) and arabis mosaic viruses (Schmel- SYMPTOMS : Chlorotic or necrotic ring and line zer and Schmidt, 1968) have been isolated singly patterns. and together, but their effects on healthy Aristo- lochia seem not to have been tested. Distribution : In A. carnea Hayne in East Germany (Schmelzer and Schmidt, 1968). Heferences Transmission : Mechanically, by inoculating infec- Lihnell, D. (1951). Nagra vardvaxter for Cucumis-virus I i tious sap to "herbaceous hosts". Sverige. Vaxtskyddsnotiser 15, 52-56. Schmelzer, K. and Schmidt, H. E. (1968). Untersuchungen an Causal agent/Relationship : Strawberry latent ring- Viren der Zier- und Wildegeholze. 6, Mitteilung : Erganzende spot virus isolated from diseased specimens but not Befunde an Caryopteris sowie Virosen an Philadelphus, confirmed as causal agent (Schmelzer, 1969). Aristolochia, Buddleja, Lycium und Aesculus. Phytopath, Z. 62, 105-126. References Brierley, P. (1944). Viruses described primarily on ornamental or miscellaneous hos ts. Pl. Dis. Reptr 150 Suppl. 410-482. BERBERIS—Berberidaceae (mimeographed). Schmelzer, K. (196 9). Das Ulrnenscheckungs-Virus. Phytopath. Foliage disease Z. 64, 39-67. Schmelzer, K. and Schmidt, H. E. (1968). Untersuchungen an Viren der Zier- und Wildegeholze. 6, Mitteilung : Erganzende SYMPTOMS : (a) Leaf mosaic characterized by red- Befunde an Caryopteris sowie Virosen an Philadelphus, Aris- dish blotches ; tolochia, Buddleja, Lycium und Aesculus. Phytopath. Z. 62, (b) varying degrees of foliar distortion 105-126. and Smolak, J. (1963). Necrosis of Aesculus hippocastanum L. Biologia Pl. 5, 59-67. (c) restriction of leaf area. Sweet, J. B. (1976). Virus diseases of some ornamental and Distribution : New York State, USA, affecting B. indigenous trees and shrubs in Britain. Acta. Hortic. 59, 83-92. thunbergii DC (Wilkinson, 1953). Sweet, J.B., Sparks, T.R. and Constantine, D.R. (1978). Im- proving the quality and the virus status of hardy ornamental trees Transmission : Mechanically, when sap from dis- and shrubs. Rep. Long Ashton. Res. Stn for 1977,36. eased host was inoculated to "herbaceous hosts". The virus identified as cucumber mosaic virus. Causal agent/Relationship : Characteristic symp- AM ELAN CH I ER—Rosaceae toms developed when Berberis seedlings were inoculated and systemically infected with an Foliage disease isolate of cucumber mosaic virus.

SYMPTOMS : Yellow ring and line patterns. Reference: Wilkinson, R.E. (1953). Berberis thunbergii, a host of cucumber Distribution : In A. vulgaris Moench in Netherlands. mosaic virus. Phytopathology 43, 489. Transmission : By grafting between A. vulgaris (van Katwijk, 1957). Causal agent/Relationship Unknown; B ETU LA—Betulaceae COMMENT: When A. canadensis (L.) Med. was See plate 18, 19, 22 (Colour) grafted with Sorbus aucuparia L. showing yellow rings and lines in the foliage, chlorotic ring and line patterns Foliage diseases developed in the A. canadensis (Kralikova, 1961). For associated virus—see under Sorbus (p 58). SYMPTOMS : Chlorotic (or in summer, white) lines forming "oak leaf" designs, irregular rings or linear References flecks, together with, in rare instances, mild mosaic. Kralikova, K. (1961). Kruzkov it ost jarabiny v CSSR. Biologia, Symptoms erratic and usually restricted to a few fully Bratisl. 16, 835-838. expanded leaves on some branches. van Katwijk, W. (1957). Een lijnenmosaiek van Amelanchier veroorzaakt door het ringvlekkenmozaikvirus van de peer. Jaarb. Distribution : On Betula papyrifera Marsh and B. PIZieklenk. Dienst 1956,165-167. alleghaniensis Britton in Eastern Canada and in the

22 • -30 a M.: Bersiee. 1973) as:: •ecfsfs (Ccs ec, 1975).

agent serfOssica ssiv!stec: iris% B. papc. ss in corny- sn a rpse I5O ats apche fl 5.00 virus cut few if dry oefesch hafiss n an isoiate C crunss hob anis Bemee, 1972) An isciabs an:ensis was seroLpg:calSi sc-hhar tio Ou -IA-Less-drily ident:cal with, aB papyr/(era solafe of acp:e mosa:c virus (Gotlieb, 1975).

COMMENTS . Expenmental graft transmissron of apple mosaic ,irus from infected apple tnduced small wn;te spots tis fomf di: leaves of B. verrucosa Kristenscn and Thomsen, 1962) The virus was recovered two years later from the birch when grafted to apple (Thomson pers coMM

I a c SYMPTOMS Diffuse mottle with chlorotic spots or I:nes in spring/summer, changing to yellow line patterns, rings and patches in autumn. Symptom excressiob erratic and partial In affected trees. Distchistich Eastern Germany (Schme:zer. 1972) and OK (Cooper and Atkinson, 1975) affecting B. verrucosa Ehrh. and B. putesceris L. Transm:ssion: Mechanica4 in extracts of pollen, roots or leaves of affected birches to infect -herbaceous hosts-. Virus occurring naturally in pollen iniects up to 75•birch seed Thebs is rib evidence suggesting that the virus is natural% transmitted between birches by soil-inhabiting nematodes (Cooper, 1976). Causal agent Ifeiationsnip The infectious agent has antigems properties in common with cherry leaf »His (CLPV), and aitnough three birch CLPV isoiates b,d many anbgemc determinants in cam- mcn, each iwas disbnguishab.!e from isolates of the virus from other genera, eg. Prunus, Sambucus Cherry, 6,S-der and birch isolates of CLFC7, propagated in "herbaceous hosts'', induced the formation of •elloW ring and line patterns one year after be:nd hicculated tu B. verrucosa seedlings (Cooper and Atkinson, 1975) a birch isolate induced 'leaf roS when inoculated to Prunus avium L. (Cooper, 1976). ehrriehtsSii infected irri cherry si Lib.< SYMPTOMS Yeiiow chevrons. oak leaf patterns anfi ringspots.

3 scfiff

Virus virus Virus infected free infected birch birch birch

Virus Virus Virus infected free infected seedling seedling ci seedling Seed Seed

2-5% 95-98% 75% . 25%

Plate 23—Diagram showing maternal and paternal factors influencing the transmission of cherry leaf roll virus to seeds of Betula verrucosa. Fewer seeds were infected when female flowers on infected trees were fertilized with healthy pollen than when virus-carrying pollen was applied to healthy trees. In these experiments, four maternal birch trees remained healthy during two seasons even though part of the seed produced carried cherry leaf roll virus. Photograph by courtesy ofNatural Environment Research Council

Distribution : Experimentally incited in Bulgaria Distribution : Locally in Northern Europe and (Atanasoff, '1967). U.S.S.R. Transmission : By grafting birch (species not given) Transmission : By grafting from B. verrucosa forma with bark from Acacia sp. naturally infected with carelica (Peterson and Vitola, 1971). Also in soil bean yellow mosaic virus. (Sakss and Banders, 1974). The characteristic Causal a ent/Relationshi : Not known. Un- anatomy developed in wood three years after fortunately. Atanasoff did not assay foliage showing seedlings of healthy B. verrucosa were grown in symptoms after grafting. soil taken from the root regions of natural Karelian birch in the U.S.S.R. SYMPTOMS : Chlorotic vein banding pattern. Causal agent/Relationship : Not known. Distribution : Unknown. One seedling of B. pub- escen.s from about 500 growing in sterilized com- COMM ENTS : The figuring in wood enhances timber post in UK showed symptoms for the first season of value for veneers. Somewhat similar syndromes of growth in a cool glasshouse. untested aetiology are reportedly widespread in Europe (Gardiner, 1965). Atanasoff (1967) speculated Transmission : Transmitted to B. pubescens neither on the possible virus aetiology of by budding nor by parasitizing dodder B. verrucosa forma Cuscuta carelica, forma gibbosa, forma callosa and forma europeaus L. Not sap transmitted to "herbaceous maseria. hosts". Causal agent/Relationshi : Two types of virus- References 'Atanasoff, D. (1967). Virus stem pitting of Birch. like particles (tubular and spherical, c 30nm diam- Z. Pflkrankh. PflPath. PfISchutz, 74, 205-208. eter) were found when sap from a leaf with Berbee. J.G. (1957). Virus symptoms associated with Birch symptoms was examined (J.I. Cooper, unpublished dieback. Bi-mon. Prog. Rep. Div. Forest Biol., Ottawa 13, 1. data). Berbee, J.G. (1959). Birch dieback : present status and future needs. Int. bot. Congr., 9th 1959,1555-1559. Cooper, J.I. (1976). The possible significance of pollen and seed COMMENTS : When assaying B. verrucosa roots, transmission in the cherry leaf roll virus (Betula spp.) complex. naturally occurring tobacco necrosis virus was detected Mitt. biol. Bundst. Ld-Forstw. 170, 17- 22. (Cooper, 1976). Cadman (cited in Schmelzer, 1972) Cooper, J.l. and Atkinson, M.A. (1975). Cherryleaf roll virus detected tobacco rattle virus in B. verrucosa causing a disease of Betula spp. in the United Kingdom. Forestry foliage with 48, 193-203. chlorotic symptoms but did not prove that the virus Gardiner, A.S. (1965). "Flamy" birch and its frequency in some caused the disease. highland populations. Scottish Forestry 19, 180- 184. Gotlieb, A.R. (1975). Apple mosaic virus infecting yellow birch in Stem disease Vermont. Proc. Am. Phytopathol. Soc. 2, 97. Gotlieb, A.R. and Berbee, J.G. (1973). Line pattern of birch caused by apple mosaic virus. Phytopathology 63, 1470-1477. SYMPTOMS : Stem grooving, pitting and figuring in Hansbrough, J.R. (1953). The significance of the fungi and wood. viruses associated with birch dieback. Report of the symposium

24 ti.ny5 o:ena:k. On.a...a. 1952. 128-135. Dept Agriculture. r.L.Loo- a BL.Cdeia . fc,Ldr" and Aesculbs. Phytopat-- Z. 62. 105- Oa r:aa a. 126. K:stensen. H R. and 7-oLmsen A. (1962). Apple mosaic vLus- 'et PL. 11969 Premieres obse-vation sur la mosaidue du h.L.st p[ants strai-.5. Ph yzepath9, Yed,rer. 2. 21-26. 3:..oc/ea caw,g, P•a7cn. dens la m:d, . ce la France. Ann. Pete'spn L. ao,d Vitola, R. (13711, (The cc:Jr-ence of stem ar..:2; 1, 627-632. pettrr g in Bircr.). Tro,j LSKt A Larvuas Lauksaynme.s, vas ST.1' < V n Ssme 7ecert Ln piant i:ruses. Akadern,as RasKsh 40 23-24 11. 96-1:93 SaKss. K. arld Bar.de's. V. (1974). (Studies Cr. grotiing th:e 'p-Lu7e va- Hc:f - A aLd Ca-on, latept ring. ..•..pc,s of Ka5?iian B,79':) For. Atstr. 38. 5923. 50»01 virus-Infected fields of Rosa rugosa produce health/ cuttings ScnmelzeL K. (1972). Das Kirchenblattroll-yrus aus der Birke cut Ts=7-h rotstcckls for standard roses. A.ledec. Fac. Land (Beru/a pendp:a Roth Zentbl. Bak:. Parasithde .46-c 1/. 127. 10- RrnsUn, v. Gen: 40 759-763. ;2.

BUXUS-Buxaceae

BUDDLEIA-Loganiaceae In a brief statement without details, Buxus simperwrens L. was said to be a natural host of arabis mosaic virus Foliage disease (Lister in Frazier et al, 1970).

SYMPTOMS : Narrowing of leaf lamina arc and ring Reference patterns. Frazier. N SV.. Fultun, JR. . Thresh, J.M., Converse, R.H.. Varney, E H. and Hewitt. W.B. (1970). p.38. Virus diseases of small fruits Distribution : In the UK (Smith, 1952). the Nether- and grape vines. Berkeley. . University of California. Division of lands (Bouwman and Noordarn, 1955) and Eastern Agricultural Sciences. Germany (Schmelzer and Schmidt, 1968) and in France (Signoret, 1969) affecting Buddleta davidn Franchet. CAMELLIA-Ternstroemiaceae Transmission : In sap to -herbaceous hosts-. Causal agent/Relationship : Cucumber mosaic Flower break symptoms and irregular chlorotic or virus was identified and Koch's postulates satisfied yellow foliar blotches have been repeatedly observed in by Schmelzer and Schmidt (1968). Camellia Japonica L.. hence the appellation 'variegated' in horticultural publications. Plakidas (1954) recog- COMMENTS . With few details. van Hoof and Carron nised another syndrome including yellow foliar ring- (1975) reported that strawberry latent nngspot virus spot patterns, in addition to the symptoms already was detected in fohage of B. davidi and that the virus described. These and a severe chlorosis in new growth was seed borne in this plant. developed when agents were transmitted by cleft grafting techniques to and from cultivars of C. japonica References and seedlings of C. sasanqua Thun. (Plakidas, 1954). Bouwman, L.W M. and Noordam. D. (1955). Komkommermo- Unequivocal proof of a virus origin is still lacking. saickvirus in Buddleia david,, Franch. Tvdschr. PIZiekt. 61, 79-81. Schmelzer. K. and Schmidt. H.E. (1968). Untersuchungen an Reference Viren der Seer- und Wildegeholze. 6. Mitteilung Erganzende Plakidas. A.G. (1954). Transmission of leaf and flower variegation Befunde and Caryoptens sowie Virosen an Philedelphus. Ans- in Camellias by grafting. Phytopathology 44, 14-18.

CARAGENA-Leguminosae

Foliage disease

SYMPTOMS Chlorotic, eventually yellow spots appearing to spread from the point of insertion of petiole into lamina to give an oak leaf vein banding effect. Distribution : In Poland affecting Caragena arborescens Lam. (Kochman and Sikora. 1968). Transmission : In sap to herbaceous hosts- Attempts to transmit the infectious agent from herbaceous plants to C. arborescens or between C. arborescens seem to have been unsuccessful (Kochman and Sikora, 1968). Causal agent/Relationship: Unknown.

Reference Plate 24-Leaves of Buddleia vanabihs showing mottle and Kochman, J. and Sikora. A. (1968). Experiments with a new virus distcrtion symptoms wnen infected with cucumber mosaic virus. disease of the pea tree (Caragena arborescens Lam.). Phytopath. Z. 61, 147-156.

25 CARPINUS-Betulaceae CASTAN EA-Fagaceae

A chlorotic line pattern on foliage has been reported on Foliage diseases Carpinus betulus L. growing in Italy : an agent was reportedly transmitted to Ostrya carpinifolia Scop. by SYMPTOMS : Leaves, apparently healthy in spring, budding and chip-grafting (Gualaccini, cited in Seliskar, albeit possibly smaller than usual, become chlorotic or 1966). Unfortunately, very scant details were provided. yellow in summer and fall prematurely in autumn. Affected trees with possibly bunched and spindly Reference branches produce few fruits. Seliskar, C.E. (1966). FAO/IUFRO Symposium on internationally dangerous forest diseases Et insects. 44. Oxford 1964. (FAO/ Distribution : Affecting Castanea crenata Sieb. and FORPEST 64-5,1966). Zucc. and C. mollissima Blume in Japan (Shimada, 1962). Transmission : By grafting but not by seed. CARY A-Juglandaceae Causal agent/Relationship : Unknown.

See plate 25 (Colour) COMMENTS : Chlorotic flecking, oak-leaf, line pattern and irregular spotting were observed in Castanea spp. Stem disease: Pecan bunch. in Italy. Agents were apparently transmitted by grafting (Gualaccini, 1959). SYMPTOMS : Branch dieback and witches' broom. Distribution : Frequent in Carya pecan (Marsh) Eng. and Graebn. and C. illioensis (Wang) K. Koch SYMPTOMS : Narrow crescent shaped and otherwise in the USA (Selsikar et al., 1974 ; Dale, 1977). deformed leaves. Transmission : By grafting affected and healthy C. Distribution : In Hungary affecting Castanea sativa pecan. (Cole, 1937). Mill. (Horvath et al., 1975). Causal agent/Relationship : Mycoplasma like Transmission : Not transmitted following mechan- organisms detected by electron microscopy (Selis- ical inoculation of herbaceous test plants (seven kar et al., 1974 ; Dale, 1977). families), or seedlings of Quercus cerris L. or C. sativa. No transmission between C. sativa with COMMENT : A somewhat similar witches' broom aphids (Myzocallis sp.). -disease,with which grafting tests do not seem to have Causal agent/Relationship : Unknown ; virus-like been done, was reported in C. ovata (Mill) K. Koch rod-shaped particles (300 x 20nm)-characteristic (Seliskar, 1966). of the tobamovirus group-were found by electron microscopy in affected C. sativa foliage. References Cole, J.R. (1937). Bunch disease of pecans. Phytopathology 27. 604-612. References Dale, J.L. (1977). Mycoplasma like organism observed in pecan Guallaccini, F. (1959). Atti del primo Convegno sulle malattie da with bunch disease in Arkansas. Pl. Dis. Reptr 61, 319-321. virus dei fruttiferi e della Vite. Pavia, 7-8 Giugno 1958. Nottz. Seliskar, C.E. (1966). FAO/IU FRO Symposium on internationally Mal. Piante 1959,47-48 (N.S. 26-27), 155-161. dangerous forest diseases Er insects. 44, Oxford 1964. (FAO/ Horvath, J., Eke, I., Gal, T. and Dezsery, M. (1975). Demonstra- FORPEST 64-5,1966). tion of virus-like particles in sweet chestnut and oak with leaf Seliskar, C.E., Kenknight, G.E. and Bourne, C.E. (1974). Myco- deformation in Hungary. Z. PflKrankh. PflPath. PflSchutz. 82, plasma li ke organisms associated with pecan bunch disease. 489-502. Phytopathology 64, 1269-1272. Shimada, S. (1962). Chestnut yellows. Pl. Prot., Tokyo, 16, 253-254.

CA RYOPTER I S-Verbenaceae CATALPA-Bignoniaceae Two viruses, alfalfa mosaic and tomato black ring, were transmitted to "herbaceous hosts" from C. incana Foliage disease Miguel showing large interveinal chlorotic or yellow patches in leaves (Schmelzer, 1 962-63; Schmelzer, SYMPTOMS : Chlorotic leaf spotting. 1968). Neither virus seerns to have been reintroduced Distribution : Affecting Catalpa bignoniodes Walt. into healthy C. incana. in Eastern Europe (Schmelzer, 1970).

References Transmission : Mechanically in leaf sap to "herb- Schmelzer, K. (1962-63). Untersuchungen an Viren der Zier und aceous hosts". Wildgeholze 3. Mitteilung : Virosen an Robinia, Caryopteris, Causal agent/Relationship : Broad bean wilt virus Ptelea und anderen Gattungen. Phytopath. Z. 46, 235-268. Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : (Taylor and Stubbs, 1972) was identified and Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2,232- proved to be a causal agent. Koch's postulates 303. Berlin : Akademie-Verlag. having been satisfied (Schmelzer, 1970).

26 CELTIS—Ulmaceae

Foliage disease

S Msr-S.MS ' .er c- sc7- .sta-,her and

Diss.triouto-n Affect ng Cegys ausgahs L. in Ita:y and Yscgos a.sa 1i-iselm: and Sans, sbpsbssbed CELASTRUS—Celastraceae da;a)

Foliage disease ageht/Relat onsh:p: Unenown, but erri SYMPTOMS: Chi sroLc motte and hngs mosaic virus (cherry leaf roll .srus) has been transmitted to -herbaceous hostss from Ceitis with Distribution : Affecting Celagrus orb/culargs symptoms (Sans, unpublished data). Tnunts, in an arboretum in East German'.

Transmission : In leaf sap to -herbaceous hosts-. COMMENT: Using Celgs foliage from Italy. repeated Causal agent/Relationship : The potato bouquet attempts faiied to detect sap transmissible virus serotype of tomato bias:ring virus was identified, (Cooper. unpublished data). but not proved to have caused trie disease with which it was associated (Schmelzer, 1974). CHIMONANTHUS—Calycanthaceae References Schmelzer, K. (1974 i. Untersunungen an Viren Der Zfer-und Foister (1961) reported with few details the trans- Wildegeholze 8. Mitteilung Neue Befunde an Foray:ha- HVdran- mission of a virus (not identified) to gea und Phdadelanus so iiie Viten und Virosen an Rharnnus, Nicovana (species Centaurea, Galvezta, Cistus. Foresuera, Abehophyllum, Celastrus, not given) from Chimonanthus fragrans Lindl. showing Saaphyiea und Craiphs. . BOKi. Fsrar.rKou:. 129.-!:, r 39-168. chlorotic mottle symptoms in the leaves.

Plate 26—Celus australis leaves showing ohlorotic mosaicsymptom associated in a few instances with cherry leaf roll virus.

27 Reference CON IFERS—Pinaceae ; Cupressaceae Foister, C. E. (1961). The economic plant diseases of Scotland. - Tech. Bull. No. 1. Department of Fisheries for Scotland, Pub- Although soil-borne viruses have been detected in the lished by H.M.S.O.. Edinburgh, 209 pp. roots of conifers (a) tobacco necrosis virus in Pinus sylvestris L. (Yarwood, 1959). CHIONANTHUS—Oleaceae (b) tomato blackring virus in Picea sitchensis (Bong) See plate 42a (Colour) Carr. (Harrison, 1964). (c) arabis mosaic virus in Chamaecyparis lawsonsiana Mixtures of the following viruses : tomato black ring, Murray (Harrison, 1964 ; Thomas, 1970). tobacco rattle and cucumber mosaic were detected in (d) tomato ringspot virus in Cupressus arizonica "herbaceous hosts" inoculated with sap from leaves of Greene (Fulton, 1969). None has been found in Chionanthus virginicus (virginica) L. showing chlorotic foliage. or necrotic ring and line patterns Schmelzer (1970). Foliage diseases: The information on foliar con- Reference Schmelzer, K. (1970). Untersuchungen an Viren der Zier-und ditions ascribed to viruses is inconclusive but some of Wildgeholze. 7. Mitteilung : Weitere Befunde an Buddleja, the salient points are discussed below. Viburnum, Caryopteris und Philadelphus sowie Viren an Leyces- "Virosis" or 'growth' asymmetry of Picea spp. was des- tene, Chionanthus, Ribes, Hydrangea, Syringa, Spiraea und cribed by Blattny (1939) and studied in greater detail Catalpa. Phytopath. Z. 67, 285-326. by Smolak (1948), Cech et al, (1961). Pintera (1955, 1960), Pintera et al. (1964) and others. In Picea excelsa (=P. abies (L) Karsten) growing in Czecho- CISTUS—Cistaceae slovakia, affected specimens reportedly have yellow- white foliage on some branches (tending to be most Foliage disease apparent in autumn and in spring) shortened needles, asymmetrically growing lateral branches and premature SYMPTOM : Yellow mottling, lines and rings in some needle .fall. Virosis was reportedly transmitted by but not all leaves. fundatrix but not alate aphids (Saccipantes abietis L. Distribution : In a botanic garden in East Germany and Cinaropsis pilicornis) (Pintera, 1955 ; Pintera et al. affecting Cistus populifolis L. and C. monspeliensis 1964). Similar symptoms were reported in P. sylvestris, L. Picea sitchensis and Picea pungens Lambert (Schmel- zer et al. 1966, Biddle, 1968 and Biddle and Tinsley, Transmission : Not obtained in sap. 1968 and Schmelzer, 1968) growing in Czechoslo- Causal agent/Relationship : Using sap from natur- vakia, Roumania, UK and USSR. Rod-shaped particles ally affected leaves of -Cistus spp. in serological of varying length (many c 625 nm) were reported in tests, reactions with alfalfa mosaic virus serum needle exudates (Cech et al. 1961) ; the particle were observed (Schmelzer, 1974). diameters ranged from 22 nm (Cech and Kralik, 1958) to 49 ± 3 nm (Cech et al. 1961). Sap from needles of Reference affected P. sitchensis Schmelzer, K. (1974). Untersuchungen an Viren der Zier-und growing in UK contained rod- Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- shaped particles up to 611, long, the cores of the particles gea und Philadelphus sowie Viren und Virosen an Rhamnus, being penetrated by the negative stain used during Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllum, Celastrus, preparation for viewing with an electron microscope. Staphylea und Crambe. Zbl. Bakt. Parasit Kde '129 Abt II, 1 39-1 68 From needles of P. sitchensis with vivid yellow-white patches, sap contained rod-shaped structures, 25 nm in diameter and up to 2/h in length or particles 35 nm in CLEMATIS—Ranunculaceae diameter by up to 5/4 long. Biddle concluded that these particles from Picea sitchensis and others detected in See plate 27 (Colour) Pinus sylvestris and P. monticola Dougl. were more likely to be crystalline storage products than virus particles. In a brief report, Thomas (1975) recorded the isolation in "herbaceous hosts" of cucumber mosaic virus from Schmelzer et al. (1966) and Schmelzer (1968) identi- Clematis x jackmanii "superba" with chlorotic leaf vein identified a condition which they named Kiefernscheck- banding and from clematis 'Vyvyan Penner with diffuse nug (pine mottling) but its infectious nature remains to chlorotic flecks around the veins. Brunt and Thomas (1975) also recorded the isolation of tobacco rattle be established. Extracts of mottled needles contained rod-shaped particles 300-600 nm long and 15 nm in virus from Clematis x heracleifolia showing chlorotic lesions in its foliage. diameter—somewhat similar to the particles associated with virosis. However, Schmelzer and his colleagues References were careful not to suggest that these were virus Brunt, A.A. and Thomas, B.J. (1975). Miscellaneous hardy particles. nursery stock. Rep. Glasshouse Crops Res. Inst., 1974, 124. Thomas, B.J. (1975). Miscellaneous hardy nursery stock. Rep. An association between irregularly spherical "virus- Glasshouse Crops Res. Inst. 1974: 119-120. sized' particles and a defoliation syndrome in Pinus

28 densiflora Sieb. and Zucc. has been described from Distribution : In USA affecting Cornus florida L. Japan (Koyama, 1970). (Waterworth and Povish, 1972). Transmission : Mechanically in leaf sap to 'herb- In West Germany, severe stunting, excessive branching aceous hosts'. and diminished needle size affecting Larix decidua Miller have been associated with rickettsia-like organ- Causal agent/Relationship : Has affinities with isms (Nienhaus et al. 1976). Transmission of these cherry leaf roll virus (CLRV) which when mechan- organisms through soil occurred when washed chopped ically inoculated to seedlings of an unnamed roots of diseased trees were mixed .with sterilized soil Cornus sp. incited chlorotic flecking along veins which was planted with tree seedlings. Following tests and transient chlorotic ringspots (Waterworth and of this type, rickettsia-like organisms were detected by Lawson, 1973). electron microscopy in root cells of L.decidua, Quercus robor L. Pseudotsuga taxifolia (Lam.) Britt. and herb- COMMENTS : Six viruses ; arabis mosaic, broad bean aceous plants including Vinca rosea L. and Cheno- wilt, cucumber mosaic, cherry leaf roll, tobacco ring- podium spp. There is no direct proof of the pathogeni- spot and tomato ringspot have been detected in C. city of these organisms. florida in the U.S.A. (Waterworth and Povish, 1972; Waterworth and Lawson, 1973 ; Barnett and Baxter, References 1973 ; Reddick et al, 1977). Arabis mosaic virus was Biddle, P.G. (1968). A study of virus diseases of forest trees. associated with white or chlorotic mosaic in some but D.Phil. Thesis, University of Oxford. not all leaves (Barnett and Baxter, 1976) but in dog- Biddle, P.G. and Tinsley, T.W. (1968). Virus diseases of conifers wood the other viruses were typically latent. in Great Britain. Nature. Lond. 219, 138-78. Blattny, C. (1939). Virova albikace u smrku (Picea excelsa). Ochr. Rost. 15, 53-54. A serologically distinct isolate of CLRV was obtained Cech, M. and Kralik, 0. (1958). 0 tyckovitych casticich dopro- from Cornus sp. in U.S.A. by J.P. Fulton but the con- vazejicich, virosu smrku (Picea excelsa). (Rod shaped particles dition of the host was not described (see Walkey et al, accompanying virus disease in P. abies). Preslia 30, 366. 1973). Cech, M.. Kralik, 0. and Blattny, C. (1961). Rod-shaped particles associated with virosis of spruce. Phytopathology 51, 183-185. Fulton, J.P. (1969). Transmission of tobacco ringspot virus to the In Europe, two syndromes have been described. roots of a conifer by a nematode. Phytopathology 59, 236. Atanasoff (1935) commented on abnormally shaped Harrison, B.D. (1964). Infection of gymnosperms with nematode- transmitted viruses of flowering plants. Virology 24, 228-229. fruits in Cornus mas L. and speculated abOut the cause. Koyama, R (1970). Mycoplasma-or virus-like particles in pine Additionally. Schmelzer observed yellow ring and line trees and in insects. J. Jap. For. Soc. 52, 126-130. patterns in leaves of C. sanguinea L. without being able Nienhaus, F., Brussel, H. and Schinzer, U. (1976). Soil-borne to detect mechanically transmissible virus in the plants. transmission of rickettsia-like organisms found in stunted and However, in a brief report. Brunt and Stace-Smith witches' broom diseased larch trees (Larix decidua). Z. PflKrank. PflPath. PflSchutz. 83, 309-316. (1971) recorded the isolation of tomato bushy stunt Pintera, A. (1955). Pokus o prenos zloutnuti jehlic smrku Korcun- virus from an unnamed dogwood with similar symp- ici Sacchiphantes abietis L. (=Chermers abietis L.). Acta Societ- toms. Furthermore. Sweet and Campbell, (1975) atis entomologicae Cechoslovenicae 52, 113-115. detected cherry leaf roll with tomato bushy stunt viruses Pintera, A. (1960). Versuche, die Virose der Fichte durch Blat- in foliage of C. sanguinea with yellow line patterns. tlause (Aphidoidea) zu umbertragen. Preslia 32. 414-415. Pintera, A., Cech, M., Blattny, C. and Pozdena, J. (1964). Symp- toms of the growth asymmetry of spruce transferred by aphids and Stem disease their relations to the presence of virus particles, ascertained by means of electron microscope. Proc. Conf. Czech. Plant Virol- SYMPTOMS : Witches' broom, proliferation of axillary ogists, 5th Prague, 1962,296-298. branches, phyllody and chlorosis of newly emerging Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2,232- leaves which remained small. 303. Berlin : Akademie-Verlag. Distribution : In New Jersey and New Brunswick, Schmelzer, K., Schmidt, H.E. und Schmidt, H.B. (1966). Virus USA affecting Cornus amomum Mill. and C. Krankheiten und virus ver dachtige Erscheinungen an Forstge- holzen. Arch. Forstw. 15, 107-120. stolonifera Michx. (Ruja et al. 1976). Smolak, J. (1948). Virosa smrku. Lesn. Pr. 27, 113-117. Transmission : Not reported. Thomas, P.R. (1970). Host status of some plants for Xiphinema diversicaudatum (Micol.) and their susceptibility to viruses trans- Causal agent/Relationship : Mycoplasma-like or- mitted by this species. Ann. appl. Biol. 65, 169-178. ganisms varying in diameter from 160-20 nm were Yarwood, C.E. (1959). Virus increase in seedling roots. Phyto- found in phloem tissue of C. amomum. The further pathology 49, 220-223. development of symptoms was suppressed temp- orarily when tetracycline hydrochloride solutions CORNUS-Cornaceae were sprayed onto leaf surfaces.

See plate 28 (Colour) References Atanasoff. D. (1935). Old and new virus diseases of trees and Foliage disease shrubs. Phytopath. Z. 8, 197-223. Barnett, O.W. and Baxter, L.W. (1973). Cucumber mosaic virus in Nandina and other ornamentals. Proc. Int. Symp. Virus SYMPTOMS : In leaves, faint chlorosis near main veins Diseases of Ornamentals, 3rd Sept. 1972.65-74. and terminal dieback. Barnett, 0.W. and Baxter, L.W. (1976). Arabis mosaic virus

29 CRATEAGUS—Rosaceae

See p'fif.e 3C: (Co ur)

Foliage disease

Chiprcitic r:ng and vein banding pa:terns. CORYLUS—Betulaceae Distribut.on : Throughout U.K. affecting Craraegos oxyacanrha Jacq. Of 97 C. oxyacantha tested by See plate 29 (Colour) bud .iiiipcisiaticyn 'wciody indicators'. Sweet (unpub.isiied data) detected 28 infections with a virus Foliage disease presumed to be CLSV: only 5 of the 28 n'ants showed symptoms. SYMPTOMS Yellow line pattern and yellow or Transm.ss,Lin : When double budded with affected chlorotic interveinal mosaic associated with nngspot material of Crataegus, symptoms dev&oped and vein banding_ woody ind:cators' ricluding : Malus platycarpa Distribution Affecting Corylus avellana L. in Italy (Posnette and Cropley, 1954, 1961 Anon. 1966). (Scaramuzzi and Ciferri, 1957) Bulgaria (Atanasoff, Causai agent/Reiationship: The symptoms in 1935) Turkey. France (Marenaud and Germain, •woody indicators resembled the disease attributed 1975) and probably wherever Corylus is widely to pear ring pattern mosaic virus (syn. apple propagated. citorotic :eaf spot virus: CLSV) (Posnette, 1957). Transmission By chip budding (Scaramuzzi and However, the symptoms in Crataegus were not &fern, 1957). always asspciated with the presumed CLSV Causal adent/Relationship: Not proven, but, in the (Sweet and Campbell, 1976). When inoculated to C. prunifolia Pers., Crataegus second season after grafting diseased Corylus from isolates of the pre- Turkey to Malus sp., foliage of the latter developed sumed CLSV induced the formation of chlorotic chlorosis (Marenaud. unpublished data). A virus rings and line patterns but these symptoms did not with serologicai and other properties in common deveioo in C. oxyacantha (Sweet. 1976). with tulare apple mosaic virus (Fulton, 1971) was isolated from Prunus persicae seedlings which had been inoculated with sap from the cnlorotic Malus fohage. A hazel with similar symptoms in U.K. contained apple mosaic virus which was detected serologicall (2.1. Cooper, D. Barbara, unpublished data). However, Sweet, et al (1978) faiied detect virus in this tree despite numerous inocula- tions to "woody indicators-.

COMMENTS A distinct syndrome in C. avellana characterized in Italy by premature defoliation and dieback was described by Corte and Pesante (1963) Although they detected a probable virus which they did not identify when -herbaceous hosts" were mechanically inoculated with hazel leaf sap, they were unable to re-establish the condition in C. avellana Plate 31—Leaves of Crataegusoxyacantha naturally infected with erre't transmissible agent resembling apple chleephe leaf spier References virus. Sembionls are eh:krone vein-banding. Atanasoff, D (1935) CH and new virus diseases of trees end - shrubs Phytopath Z. 8 197-223,

30 COMMENTS : When budded to 'woody indicators', an properties in herbaceous test plants. Four distinct individual of C. korolkowi (Syn. C. wattiana Hemsl. and viruses having rod-shaped particles of different modal Lace) which had foliar chlorotic ring and line patterns length but of unproven pathogenicity have been detec- induced symptoms which Sweet and Campbell (1976) ted in Daphne plants in New Zealand (Forster and considered atypical of any known virus of pome fruit Milne, 1975). Because of their superficial similarities to (ie. fruit with a 'core' eg. apple, quince, pear etc.). members of the tobamo, potex, carla and potyvirus groups respectively, these were named Daphne-TMV, Yellow spots with mottling of foliage were experimen- Daphne viruses X. S and Y. (Forster and Milne, 1975). tally induced when buds of apple infected with apple Foliar chlorotic mosaic symptoms with distortion in D. mosaic virus were grafted to C. oxyacantha (Kristensen odora "Leucanthe" or "Rubra" and necrotic flecks in and Thomsen, 1962). "Leucanthe Alba" were associated with Daphne virus Y (Forster and Milne, 1976). References In the U.K., Thomas (1975) isolated a potyvirus from Anon. (1966). A standard minimum range of woody indicator D. mezereum with yellowish rings and general leaf varieties for fruit tree viruses in Europe. Zast. Bilja 16, 543-545. chlorosis but did not present proof that the virus caused Kristensen, H.R. and Thomsen, A. (1962). Apple mosaic virus- the associated symptoms. In the U.K., tomato black host plants strains. Phytopathol. Mediter. 2, 21-26. Posnette, A.F. (1957). Virus diseases of pears in England. J. hon. ring virus has been isolated from symptomless D. retusa Sci. 32, 53-61. Hemsl. (Forster, unpublished data). Posnette, A.R. and Cropley, R. (1954). Distribution of rubbery wood virus in apple varieties and rootstocks. Rep. East Mailing References Res. Stn. 1953 150-153. Boning, K. (1963). Die Notwendigkeit der virus Kontrolle von Posnette, A.F. and Cropley, R. (1961). Indicator plants for latent Zierholzgewachsen in Baum schulen. Mitt. biol. BundAnst. Ld- virus infection in apple. J. hon. Sci. 36, 168-173. u. Forstw. 108, 16-22. Sweet, J.B. (1976). Virus diseases of some ornamental and in- Forster, R.L.S. and Milne, K.S. (1975). Survey of viruses infecting digenous trees and shrubs in Britain. Acta Horticulturae 59, 83-90. daphne in New Zealand. N.Z. J. agric. Res.18, 391-398. Sweet, J.B. and Campbell, A.I. (1976). Pome fruit virus infections Forster, R.L.S. and Milne. K.S. (1976). Daphne virus Y : poty of some woody ornamental and indigenous species of Rosaceae. virus from daphne. N.Z. J. agric. Res.19, 359-371. J. hort. Sci. 51, 91-9. Frazier, N.W.. Fulton, J.P., Thresh, J.M., Converse, R.H., Varney. E.H. and Hewitt, W.B. (1970). Vfrus diseases of small fruits and grape vines. Berkeley : University of California, Division of Agricultural Sciences. DAPHNE-Thymelaeceae Hollings, M. (1961a). Virus and its effect on some ornamental shrubs. Nurserym. Seedsm. Glasshouse Grower 1961,930-931. See plate 32 (Colour) Hollings, M. (1961b). Virology. Rep. Glasshouse Crops Res. Inst. 1960. Foliage disease Hollings, M. and Stone, O.M. (1970). Carnation mottle virus C.M.I.IA.A.B. Descr. Plant Viruses no. 7,4 pp. SYMPTOMS : Yellow ring and line patterns in leaves Milbrath. J.A. and Young, R.A. (1956). Cucumber mosaic virus associated with defoliation or dieback. and alfalfa mosaic virus isolated from Daphne odora. Pl. Dis. Reptr 40, 279-283. Distribution : Worldwide in Daphne mezereum L. Morris-Krsinich, B. (1976). Characterization of three isometric and D. odora Thunb. virus infecting daphne. M. Hort. Sci. Thesis. Massey University, Transmission : In sap to 'herbaceous hosts'. New Zealand. Smith, K.M. (1972). A textbook of Plant Virus Diseases. 3rd Edn Causal agent/Relationship : Whereas cucumber Edinburgh, Longman. mosaic virus was frequently associated with these Thomas, B.J. (1975). Miscellaneous hardy nursery stock. Rep. symptoms (Boning, 1963 ; Smith, 1972) the virus Glasshouse Crops Res. Inst. 1974,119-120. was also isolated from forty five symptomless plants of D. odora, fifteen of which also contained alfalfa mosaic virus (Milbrath and Young, 1956). Follow- ing a different series of observations, Hollings DIOSPYROS-Ebenaceae (1961 a and b) suggested that the slight mottling in leaves of D. mezereum associated with alfalfa A range of symptoms has been observed in Diospyros, mosaic virus was greatly aggravated by the presence including leaf mottling, veinal necrosis, leaf malforma- of cucumber mosaic virus. tion, premature defoliation and flower fall, necrosis in the wood, internal necrotic spots in the fruit and dieback. COMMENTS : The genus is liable to frequent virus in- Mezzetti (1950) in Italy reported transmission : some of fection, complex mixtures seem common and know- these symptoms formed in healthy plants after grafting ledge of disease aetiology lacking. A survey of thirteen with diseased scions. An unidentified virus has been Daphne species in New Zealand (Forster and Milne, transmitted mechanically to "herbaceous hosts" from 1975) revealed arabis mosaic virus (it was previously an affected Diospyros sp. in Brazil (Herbas, 1969). reported in Daphne in U.K., see Lister, in Frazier et al, 1970), tobacco ringspot as well as cucumber and References Herbas, A.R. (1969). El mosaico del caqui (Diospyros kaki) y alfalfa mosaic and three viruses, two of which were algunas propiedades des Fisicas de su agente causal. Turrialba subsequently (Morris-Krsinich, 1976) identified with 19, 480-490. carnation mottle (Hollings and Stone, 1970) and Mezzetti, A. (1950). Altre osservaxioni sulla "defogliazione del isolates of cucumber mosaic having unusual host range Kaki". Annali Sper. agr. N.S., 4, 291-294.

31 ESCALLONIA—Saxifragaceae

In a brief report. Thomas (1975) recorded the isolation in herbaceous hosts of cucumber mosaic virus from E. rosea Griseb. with severe leaf chlorosis.

Reference Thomas B J (1975). Miscellaneous hardy nursery stock. Glasshouse Crops Res. Inst. 1974,119 - 120.

EUCALYPTUS—Myrtaceae

In 1963. Foddai and Marras working in Italy (see Schmelzer. 1968) reported a graft transmissible witches' broom type disease in E. rostrata Schlecht. The witches' broom was associated with leaf malformation chlorosis and vein yellowing but the causal agent has not been determined. In India. Sastry et al. (1971) detected in E. citriodora Hock. a virus resembling tobacco mosaic: its significance is unknown.

References Sastry. K.S.M., Thakur, R.N.. Gupta, J.A. and Pandotra. V.R. (1971). Three virus diseases of Eucalyptus candodora. Indian Phytopath. 24. 123-126. Plate 34 —Euonyrnus japonicus fasciation reportedly associated Schrnelzer, K. (1968). Zier-. Forst- und Wildgeholze. In : in some instances with rhabdovirus-like particles. Pflanzliche Virologie edited by M. Klinkovvski. vol. 2 part 2, 232– 303. Berlin : Akadernie-Verlag. Photogran» by courtesy or G Jonsson

EUONYMUS—Celestraceae Distribution : In USA affecting E. kiautschovica See plate 33 (Colour) Loesner and E. fortunei var vegeta. Transmission : Mechanically in foliar sap inocu- Fo I iage diseases lated to -herbaceous hosts-, by dodder (Cuscuta campestns), grafting and nematodes (Xiphinema SYMPTOMS : Vein clearing. spp.) but not in seed (Puffinberger and Corbett, Distribution : Widespread in Europe affecting the 1973). cultivated Euonymus fortune! ; (E. radicans Sieb.) Causal agent/Relationship : Not proven; an isolate and E. japonicus Thunb. (Baur. 1908) and the named euonymus ringspot virus had properties in native E. europaeus L. (Schmelzer, 1969). common with nepoviruses but was not serologically Transmission : By grafting from affected to healthy related to those (unnamed) tested. E. europaeus (Schmelzer. 1969). The symptoms were associated with a virus transmitted mechan- SYM PTOMS : Bright yellow blotches and rings. ically when Euonymus leaf sap was inoculated to Distribution In USA (Barnett and Baxter, 1973) "herbaceous hosts-. UK and the Netherlands (Cooper, unpublished) Causal agent/Relationship : Not proven. Schmel- affecting E. japonicus cv microphyllus Hort. zer, (1969) associated strawberry latent ringspot Probably widespread in this cultivar. virus. Transmission : Mechanically, in sap to "herbaceous hosts". COMMENTS : Bojansky and Kosljarova (1968) tenta- Causal agent/Relationship: In all tested plants, tively associated green-yellow spotting and leaf vein cucumber mosaic virus was associated with the banding in E. europaeus with a virus transmitted by disease but not shown to be its cause. aphids (Aphis euonymi F.). Subikova et al. (1974), using the same source material. identified tobacco COMMENTS : Rhabdovirus-like particles were found necrosis virus (Kassanis, 1970) which is normally in fasciated but not symptomless specimens of E. transmitted by soil-inhabiting fungi. japonica (probably E. japonicus) (Jonsson, 1974).

SYMPTOMS : Chlorotic rings and oak leaf patterns in With few details, Codaccioni and Cossard (1977) young leaves. reported that the virus-like particles were transmitted

32 and infectious for Euonymus but did not prove that they thought to be natural vectors (Flock and Wallace, caused fasciation. 1955). Successful spread via seeds has not been recorded. Sowbane mosaic virus (Kado, 1971) References was detected following mechanical transmission of Barnett, O.W. and Baxter, L.W. (1973). Cucumber mosaic virus fig sap to 'herbaceous' hosts on Nandina domestica in South Carolina. Pl. Dis. Reptr 57, 917- (Quacquarelli, 1971). 920. Causal agent/Relationship: Unknown. Baur, F. (1908). Uber eine infektiose Chlorose von Euonymus japonicus. Ber. dt. bot. Ges. 26, 711-713. References Bojansky, V. and Kosljarova, V. (1968). Euonymus mosaic. Ainsworth, G.C. (1935). Fig mosaic. JI. R. hon. Soc. 60, 522- Biologia Pl. 10, 322-324. 523. Codaccioni, M. and Cossard, C. (1977). Transmission experi- Condit. I.J. and Horne, W.T. (1933). A mosaic of the fig- in mentale de particles du type rhabdovirus, naturellment presentes California. Phytopathology 23, 887-896. dans les tiges fasciees d'une variete de Fusain. C.r. hebd. Seanc. Condit, I.J. and Horne, W.T. (1941). Further notes on fig mosaic. Acad. Sci. Paris. 284, 701. Phytopathology 31, 561-563. Jonsson, G. (1974). Localisation nucleaire et cytoplasmique de Flock, R.A. and Wallace, J.M. (1955). Transmission of fig mosaic particules d'allure virale chez des sujets fascies de Fusains by the eriophyid mite Aceria ficus. Phytopathology 45, 52-54. (Euonymus japonica Thunb. et var. microphylla Jaeger). Revue Kado, C. I. (1971). Sowbane mosaic virus. C.M.I./A.A.B. Descr. gen. Bot. 81, 135-150. Pl. Viruses No. 64,4pp. Kassanis, B. (1970). Tobacco necrosis virus. C.M.I.IA.A.B. Quacquarelli, A. (1971). ll mosaico del fico e il virus latente del Descr. Plant Viruses no. 14,4 pp. Chenopodium. Phytopathologia Meditteranea 10, 283-286. Puffinberger, C.W. and Corbett, M.K. (1973). Characterization of a NEPO virus isolated from Euonymus. Phytopathology 63, 804. Schmelzer, K. (1969). Das Latente Erdbeerring flecken-virus aus Euonymus. Robinia und Aesculus. Phytopath. Z. 66, 1-24. FO R ESTI ERA-Oleaceae Subikova, V., Baumgartenerova, H. and Bojnansky, V. (1974). Purification electron microscopy and serology of virus isolated Foliage disease from Euonymus europaea. Biologia Pl. 16, 321-324. SYMPTOMS : In spring, light and dark green mottling and distortion ; later formed leaves were larger and had FAG US-Fagaceae fewer symptoms. Distribution : In a botanic garden in East Germany Rankin (1928) reported that beech (Fagus sylvatica L.) affecting Forestiera acuminata (Michx.) Poir. in the USA was liable to show chlorotic symptoms Transmission : In sap to "herbaceous hosts" in- which did not disappear when solutions of mineral oculated with foliar sap from young (but not old), nutrients were applied. In East Germany, chlorotic or leaves in summer. yellow rings and flecks were observed in leaves of F. Causal agent/Relationship : The potato bouquet sylvatica (Schmelzer et al. 1966). These workers did serotype of tomato black ring virus was associated, not report attempts to detect viruses in this material but but not proved to cause the disease (Schmelzer, cited an unpublished observation by Cadman who 1974). transmitted tomato black ring virus from leaves with these symptoms collected in Scotland. References Schmelzer, K. (1974). Untersuchungen an Viren der Zier-und Reference Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- Rankin, W.H. (1928). Mottle leaf disease of beech. Phytopath- gea und Philadelphus sowie Viren and Virosen an Rhamnus, ology 18, 151. Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllurn, Celastrus, Schmelzer, K., Schmidt, H.E. und Schmidt, H.B. (1966). Virus Staphylea und Crambe. Zbl. Bakt. Parasit Kde 129, 139-168. Krankheiten und virus ver dachtige Erscheinungen an Forst- ge holzen. Arch. Forstw. 15, 107-120. FORSYTH IA-Oleaceae

FICUS-Moraceae Foliage disease See plate 35 (Colour) SYMPTOMS : Vein yellowing, yellow net. Foliage disease Distribution : Widespread in Europe and recorded from the USA affecting Forsythia intermedia Zabel, SYMPTOMS : Mosaic irregular green-yellow blotches F. suspensa (Thunb.) Vahl. and F. europaea Deg some with red margins and premature leaf fall (Ains- et Bald. worth, 1935) also fruit spotting (Condit and Horne, Transmission : By grafting and by mechanical in- 1933; 1941). oculation of "herbaceous hosts" with sap from Distribution : Although first reported from Californ- affected Forsythia leaves (Schmelzer and Schmidt, ia, USA, the disease seems prevalent wherever 1959 ; Tiangco and Varney, 1970 ; Schmelzer, Ficus carica L.. F. stipulate Thu nb. F. altissima 1957; 1962/63; 1974). Blume and F. krisna DC are grown. Causal agent/Relationship : In East Germany the Transmission : By grafting in conditions reportedly causal association of arabis mosaic virus (AMV) free of eryiophyid mites (Aceria ficus Cotte) with yellow net was proved by inoculating coty-

33 FRAXINUS Oleaceae

zer, 196S). A d atsett La6? .y! ,s;If

• -La l•AffafaSf a .1 17 di It trasarrteted tier

,te sessramti ttn stOlk after nut.. ,e-vere, inn tsrerrnature leaf iflcats, F-r Mas tre cut/veer.. There ne PH/ice lad/. 233 •1733 Sc fimalzer. K. (l fipd) Dds f;:r. r r,res ref this agent or its pessiftie Z. 64, 39-67. psP:t.c.,pspps. McsaH mettLng %At: eistsamon et leaflet Senmelzar, K. (16/4l Larap., .ansirae Las Ppen reprrtee from Benttara Atanasaff, Wildealiff.ze 8. Mira-Han-I [67`..:;17.a 1935t, naly (eaf marrhrg, marrneregiTatura: &fern et 1951), Fast Germany (grummosa-e, Sermelzer, 19n2. 6"» am; rse UF (nersena. ebrserstat sr). Attenictn Schmelder. K. anl Soh.- fit H7) D Fli:pt Genstenty arm, FiK te trarsm r twe c -fecr 'don :-;.; hett der Has/thie Pa, 77.12,3; Z. 36 17-30

irl /-. 0.7.0 K. failed. Slfangel7, tl ere are f Pa-

mrermedra leaves showing the range of arpLar:s (free: yell 7.4.. virile ta almost normal green) wham alnencanh seadlina sheadnd clderf6tie aLaurull7 infected wall rdsyneriv rindspar. virus. drraed f6llfriyind url,--cha:iral ;macula- sia:l.ersis. red nEthnirrrea s(3'1,:s and nuds: symptom

1S!73i) USsr D Str hut: on ',Ihrtheastrn states of USA affec- tind » ame../Fdna L. asd F. perinsylvamd Marcn ;ar lai seolata Sang (Hibben, 1966 b) TransTrassiOn giaftind and folioNing sap in- huuldt hn of hesbaceous hosts '. (Hibtsen, 1966 a arid b) Foliage diseases Causal adeut/Relationship, An Isolate from F ;.,,,/,erFaana Cak: leaf patterrs possessed anmenic determinants in common and cLeyrons c..r msd mottle . :sums erratically and with tobacco ringspot virus (Hibben and partiaS7 expressed. Buzartn, 1972) but the extent of the relationship could not be determined from this work (Scott, 1973) Distribution: In UK (Cooper, 1975) affecting Fra>.Faus exceNFr COMMENTS In common with tobacco ringspot virus' Transmission: In fohar sao to snerbacebus hostU. isolates from other hosts, ash isolates are spread in soil Causal agent/Fielationsinp: Araby., mosaic virus. by nematodes, Xiphsnema amencanum Cobb. (Hibben having few if ariu anHerlik determinants not and Walker, 1971 a and 5). Athough it is probable that posseaseisi by a sugar 1*/: isckate AHil 0 (Harrison, ash isolates of the virus are transIocated from roots to 1302) , ssyscs detected in leac.,c; yvitri symptums hst leaves. this is not proven and Kochs postulates have not d In leaflets yvi thou', symptoms on tke same trees oeen fully satisfied. Following manual inoculation, The saros ca.bsed sMoratu symptoms in burage tobacco nngspot virus infected leaves of F. permsyl- inucuidtnnl F. excie/uor scesianiits t»Fcli) it 'ohs varuica causing a mosaic and narrowing of leaflets r 1976) (VVilkinson. 1952)

Plsso 47 —Leaves of Fraxynos excelsior showing concentric rh•nrchin local lesinns which formed following mechanical Fraonos hloruti/ rin/j Plare 40—Le5fi/rs ci rh1;ift n •.Ahth inn virus resembling tobacco mosaic. and line r; ,11/-rns ii,lectcH virus resemLlinu

35 SYMPTOMS : Chlorotic ring and line patterns with observed. Although attempts to satisfy Kochs leaf distortion. postulates have not been reported, circumstantial Distribution : In . one nursery in UK affecting evidence favours the view that MLO may play a Fraxinus americana on F. excelsior rootstocks part in both the witches' broom and in the dieback (Cooper and Sweet, 1976). syndromes described in F. americana. Transmission : In sap to "herbaceous hosts". COMMENTS : Plakidas (1949) observed a witches' Causal agent/Relationship : Arabis mosaic virus broom syndrome in F. berlandierana DC and reported possessing few if any serological determinants not transmission between F. berlandieiana by grafting held in common with sugar beet and F. excelsior but the published data suggest that it was a dieback isolates was indentified and caused puckering with rather than a witches' broom which developed and then chlorotic line pattern symptoms in systemically in only one of an unspecified number of plants. infected foliage of inoculated F. americana seed- A somewhat similar syndrome was observed in F. ornus lings. growing in Italy (Ciferri et al, 1961) although vein clearing followed by vein necrosis seemed the more COMMENTS : Ring and line pattern symptoms were common symptom. The agent was reportedly trans- observed in F. americana in Massachusetts, USA (Lana mitted to F. excelsior and F. ornus by chip budding but and Agrios, 1973, 1974) and the syndrome developed few details of the experiment were given. in F. americana and F. pennsylvanica seedlings budded with the diseased material. A virus having serological and other properties in common with tobacco mosaic References Atanasoff, D. (1935). Old and new virus diseases of trees and virus was detected in "herbaceous hosts" inoculated shrubs. Phytopath. Z. 8, 197-223. with leaf sap from the diseased Fraxinus. Furthermore, Casalicchio, G. (1965). La punteggiatura cloro-necrotica del rod-shaped virus-like particles "some of which were Fragsino maggiore. (Chloro-necrotic spotting of ash). Monti similar in shape and size to tobacco mosaic virus" were Boschi 16, 39-46. revealed when partially clarified sap from diseased ash Cifferi, R., Corte, A. and Rui, D. (1961). Due virosi del frassino "arricciamento" fogliare con necrosi e la marmoreggiatura fogliare. foliage was examined in an electron microscope. Riv. Patol. veg., Padova. Ser. Ill, 241-250. Attempts to reintroduce the virus in sap from "herb- Cooper, J.I. (1975). Arabis mosaic virus, a cause of chlorotic aceous hosts" into healthy F. americana and F. penn- symptoms in leaves of Fraxinus excelsior L. Pl. Path. 24, 114-116. sylvanica were reportedly unsuccessful although Cooper, J.I. and Sweet, J.B. (1976). The detection of viruses with chlorotic local lesions formed in inoculated leaves of nematode vectors in six woody hosts. Forestry 49, 73-78. Harrison, B.D. (1958). Raspberry yellow dwarf, a soil-borne F. excelsior. This "target" symptom is somewhat virus. Ann. appl. Biol. 46, 221-229. similar to a syndrome noted in Italy on F. excelsior and Hibben, C.R. (1966a). Graft transmission of a ringspot-like virus described as "punteffiatura chlor-necrotica" (Casalic- from White Ash (Fraxinus americana). Pl. Dis. Reptr 50, 905-906. chio, 1965). Although a sap transmissible virus having Hibben, C.R. (1966b). Transmission of a ringspot-like virus from properties in common with tobacco necrosis virus was leaves of white ash. Phytopathology 56, 323-325. apparently associated with the disease in Italy, no un- Hibben, C.R. (1973). Sequential development of virus-like ambiguous identification was made and attempts to ex- symptoms in ash over a six-year period. Pl. Dis. Reptr 57, 396- 399. amine the effect of the isolate on healthy F. excelsior Hibben, C.R. and Bozarth, R.F. (1972). Identification of an ash were not reported. strain of tobacco ringspot virus. Phytopathology 62, 1023-1029. Hibben, C.R. and Walker, J.T. (1971a). Nematode transmission of ash ringspot virus. Phytopathology 61, 129. Stem disease Hibben, C.R. and Walker, J.T. (1971 b). Nematode transmission of the ash strain of tobacco ringspot virus. Pl. Dis. Reptr 55, 475- SYMPTOMS : Witches' broom. In Fraxinus americana, 478. diseased foliage was simple rather than pinnate, chlor- Hibben, C.R. and Wolanski, B. (1971). Dodder transmission of a otic and borne on abnormally erect branches some mycoplasma from ash witches' broom. Phytopathology 61, 1 51- 156. derived from precocious axillary and terminal bud Lana, A.O. and Agrios, G.N. (1973). A disease of white ash growth. caused by tobacco mosaic virus. Phytopathology 63, 203. Distribution : The syndrome was probably first Lana, A.O. and Agrios, G.N. (1974). Transmission of a mosaic described (1947) from USSR (Kuprevicz, cited in disease of white ash to woody and herbaceous hosts. Pl. Dis. Reptr 58, 536-540. Schmelzer, 1968) but more intensively studied in Novak, J . (1969). Investigation of virus diseases of lilac. Proc. the USA where it was observed in New York State Conf. Czech. Plant Virologists, 6th Olomouc (1967), 289-293. (Hibben and Wolanski, 1971). Plakidas, A.G. (1949). Witches' broom, a graft-transmissible disease of Arizona ash (Fraxinus berlandieriana). Phytopathology Transmission : By dodder (Cuscuta subinclusa 39, 498-499. Dur. and Hilg. and C. campestris Yuncker) from Schmelzer, K. (1962/63). Untersuchungen an Viren der Zier und affected F. americana to Vinca rosea L. cv Little Wildgeholze 3. Mitteilung : Virosen an Robinia, Caryopteris, Pinkie. Ptelea und anderen Gattungen. Phytopath. Z. 46, 235-268. Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : Causal agent/Relationship : Elongated ovoid and Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2,232- 303. Berlin : Akademie-Verlag. filamentous MLO were observed in the phloem Scott, H.A. (1973). Letter to the editor-Interpretations of gel tissue of roots and mid veins of leaves of F. ameri- diffusion tests. Phytopathology 63, 439, cana and also in C. campestris parasitizing the Wilkinson, R.E. (1952). Woody plant hosts of the tobacco ring- diseased V. rosea into which transmission was first spot virus. Phytopathology 42, 478.

36 FUCHSIA—Onagraceae gea und Philadelphus sowie Viren and Virosen an Rhamnus, Cenraurea, Galvezia. Cistus. Forestiera. Abeliophyllum, Celastrus. Staphylea und Crambe. Zbl. Bakt. Parasit Kde 129, 139-168. Uschdraweit (1955) reported anthocyanescence and Schwenk. F.W.. Williams, H.E. and Smith, H.S. (1969). Alfalfa narrowing of I eaves, stunting and impaired flower mosaic virus from Hebe. Ilex and Viburnum. Phytopathology 59, formation in Fuchsia spp. from South America and that 1048-1049. symptoms developed in stocks (unspecified) grafted with diseased scions. HEDERA—Araliaceae Reference Uschdraweit. H.A. (1955). Eine Viruskrankheit bei dar Gattung See plate 43 (Colour) Fuchsia. Ganenwelt Berl. 55, 147-148. Foliage diseases

GALVEZIA—Scrophulariaceae SYMPTOMS : Chlorotic-yellow vein banding, blotches or broad ring patterns. Foliage disease Distribution : Affecting H. helix L. in several counties of the UK. SYMPTOMS : Leaves on some shoots were mottled and curled with slight necrosis. Transmission : In sap to "herbaceous hosts". Distribution : An individual of Galvezia speciosa Causal a ent/Relationshi : Arabis mosaic virus A. Gray from Chile in an East German botanic (AMV) was consistently associated but in one garden. instance occurred with strawberry latent ringspot virus (SLRV). Although both viruses systemically Transmission : In sap to "herbaceous hosts". infected H. helix seedlings, yellow symptoms were Causal agent/Relationship : Virus identified as caused by neither AMV alone nor mixtures with broad bean wilt but not proved to be the cause of SLRV (Cooper and Sweet, 1976). the symptom (Schmelzer, 1974). COMMENTS : The foliar symptoms in H. helix re- Reference semble those described as ivy ringspot virus, a disease Schmelzer. K. (1974). Untersuchungen an Viren der, Zier-und Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- recorded but not apparently studied in Roumania gea und Philadelphus sowie Viren and Virosen an Rhamnus, (Ploaie and Macovei, 1968). Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllum, Celastrus, In France, tubular rod-shaped virus-like particles were Staphylea und Crambe. Zbl. Bakt. Parasit Kde 129, 139-168. found when fasciated H. helix was examined ; the presumed virus was not shown to cause the abnormality GLEDITSIA—Leguminosae (Witz et al, 1972).

References A witches' broom syndrome is reported to affect G. Cooper, J.I. and Sweet. J.B. (1976). The detection of viruses triacantos L. in the U.S.A. (Grant and Hartley, 1938) with nematode vectors in six woody hosts. Forestry 49, 73-78. and Atanasoff (1935) recorded a deforming mosaic Ploaie, P.G. and Macovei, A. (1968). New plant virosis recorded symptom without witches' broom in Bulgaria. Neither in Roumania. Revue. roum. Biol. (Ser. Bot.) 13, 269-274. (For. disease has been studied in detail and their relationship Abstr. 30,4218). if any to conditions reported in Robinia pseudoacacia L. Witz, J., Hirth, L., Wurtz, M.B. and Plantefol, L. (1972). Etude morphologique de particules en batonnet extraites des Feuilles de remains to be established. lierres (Hedera helix L.) anormaux. C. r. hebd. Seanc. Acad. Sci. Paris (Ser. D) 275, 2437-2441. Reference Atanasoff, D. (1935). Old and new virus diseases of trees and shrubs. Phytopath. Z. 8, 197-223. Grant, T.J. and Hartley, C. (1938). A witchesbroom on black HYDRANGEA—Saxifragaceae locust and a similar disease on honeylocust. Pl. Dis. Reptr 22, 28-31. Foliage disease

SYMPTOMS : Leaves crinkled, rolled or asymmetric HEBE—Scrophulariaceae (distorted), fewer and smaller florets on short stalks in the cymes (Brierley and Smith, 1952 ; Brierley and In a brief report Schwenk et al, (1969) recorded the Lorentz, 1957). isolation of alfalfa mosaic virus from Hebe sp. The Distribution : Affected H. macrophylla Thunb. are authors did not state whether or not symptoms were found worldwide. associated with the infection. Schmelzer (1974) Transmission : Several distinct viruses transmitted reported that Hebe bolonsii CKn was susceptible to mechanically in leaf sap to "herbaceous hosts-. experimental infection with elm mottle virus. Causal agent/Relationship : Hydrangea ringspot References Schmelzer, K. (1974). Untersuchungen an Viren der Zier-und virus (Koenig, 1973), which is only recorded from Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- hydrangea and which is spread on pruning knives

37 and mechanically by leaf contact, but neither in diseased hydrangea foliage (Muller, 1971 ; Amici seed (Brier ley and Lorentz, 1957) nor by aphids et al. 1972 ; Welvaert et al. 1975 ; Hearon et al. (Hollings, 1958), caused the development of 1976). chlorotic or brown spots or rings in distorted leaves (Brier ley and Smith, 1952). In the USA, Brier ley References (1954) transmitted tomato ringspot virus from Amici, A., Granicini, P., Osler, R. and Refatti, E. (1972). Disorders chlorotic hydrangeas and considered it somewhat probably caused by mycoplasmas in various plant species in Italy. Riv. Patol. veg. Pavia. Ser. IV, 8, 21-50. more damaging than hydrangea ringspot virus. Anderson, C.W. (1958). Tobacco ringspot virus on florist's Tobacco ringspot has also been recorded in the Hydrangea. Pl. Dis. Reptr, 42, 932-933. USA from hydrangea (Anderson, 1958), whereas Anon. (1933). Bericht der Lehr- und Forschungsanstalt fur Wein-, in Europe, Schmelzer (1970) detected tomato Obstund Gartenbau zu Geisenheim am Rheim, 1931-32. Landw. blackring, arabis mosaic and tobacco rattle viruses Jbr. 77 Suppl.. 217-247. Belli, G. (1968). Researches on a vein clearing of Hydrangea. associating foliar mosaic symptoms in H. macro- Phytopath. Mediter. 7, 70-71. phylla with TRV and AMV when present together. Brierley, P. (1954). Symptom in the florists' hydrangea caused by Viruses having aphid vectors have also been associ- tomato ringspot virus and an unidentified sap-transmissible•virus. ated with the syndrome. Phytopathology, 44, 696-699. Brierley, P. and Lorentz, P. (1957). Hydrangea ringspot virus, the probable cause of "running out" of the florists's hydrangea. Foliar mosaic and leaf distortions have been Phytopathology 47, 39-43. attributed to cucumber mosaic virus in Japan Brierley, P. and Smith, F.F. (1952). A ringspot virus from Hydran- (Tamura and Komuro, 1967) whereas alfalfa gea infectious to herbaceous plants. Pl. Dis. Reptr 36, 382-383. mosaic virus is a probable cause in Italy of foliar Brierley, P. and Smith, F.F. (1954). New records of virus diseases vein clearing (Belli, 1968). Irrespective of the of ornamental plants. PI. Dis. Reptr 38, 739-741. Dunez, J. (1963). Une maladie a virus rencontree recemment en associated virus, symptoms expressed differ with France, le "ringspot" de l'Hortensia. Ann. EpiPhyt. 14, 103-108. cultivar and are dependent on environmental Hearon, S.S., Lawson, R.H., Smith, F.F., Mackenzie, J.T. and conditions. Rosen, T. (1976). Morphology of filamentous forms of a mycoplasma-like organism associated with hydrangea virescence. COMMENTS : Kristensen (1962/64) recorded the iso- Phytopathology 66, 608-616. Hollings, M. (1958). Hydrangea ringspot in Britain. J. hort. Sci. lation in "herbaceous hosts" of tobacco necrosis virus. 33, 275-281. Neither details of the associated symptoms in Hydrangea Koenig, R. (1973). Hydrangea ringspot virus. C.M.I.IA.A.B. sp nor the properties of the virus were given. Descr. Plant Viruses. no. 114.3 pp. Kristensen, H.R. (1962/64). Plantesygdome i Danmark-virus- sygdome. Tidsskr. PlAyl. 67, 596. Muller, H.M. (1971). Electronen mikroskopischer Nachweis von Stem disease Mycoplasmaahnlichen Organismen in Phloem von Hydrangea macrophylla. Zentbl. Bakt. Parasitkde. Abt II, 126, 564-565. SYMPTOMS : Witches' broom / phyllody. Cymes Schmelzer, K. (1970). Untersuchungen an Viren der Zier-und Wildgeholze. 7. Mitteilung : Weitere Befunde an Buddleja, (heads) of flowers dwarfed with the individual flowers Viburnum, Caryopteris und Philadelphus sowie Viren an Leyces- or florets green instead of pink, white or blue ; leaf-like teria, Chionanthus, Ribes, Hydrangea, Syringa, Spiraea und structures originating from the female parts of flowers Catalpa. Phytopath. Z. 67, 285-326. (pistils). In some instances leaves have vein yellowing Tamura, M. and Komuro, Y. (1967). The mosaic disease of and may be unusually small. Hydrangea caused by cucumber mosaic virus disease. Ann. phytopath. Soc. Japan, 33, 27-31. Distribution : Widespread in florists' hydrangea Welvaert, W., Samyn, G. and Lagasse, A. (1975). Recherches sur Diseased H. macrophylla noted in West Germany les symptomes de la virescence chez l'Hydrandrangea macrophylla Anon, 1933), the USA (Brierley and Smith, 1954) Thun b. Phytopath. Z. 83. 152-158. and France (Dunez, 1963). Transmission : By grafting from diseased to pre- I L EX- A quifoliaceae viously healthy hydrangeas (Dunez, 1963; Hearon et al, 1976). Welvaert et al. (1975) induced Foliage disease phyllody in Vinca rosea L. joined to diseased hydrangea by the parasitic Cuscuta subinclusa but SYMPTOMS : Chlorotic-yellow spots in young leaves Hearon et al. (1976) did not transmit the agent of and irregular margins in older leaves. disease using C. campestris Yunck. to bridge diseased hydrangeas with a range of "herbaceous Distribution : In Maryland, USA affecting Ilex hosts" including V. rosea. crenata var rotundifolia (Waterworth and Povish Whereas Brierley and Smith (1954) reported that 1977). leafhoppers that fed on diseased hydrangeas in- Transmission : To "herbaceous hosts" inoculated duced aster "yellows" in China aster (Callistephus with sap from young leaves triturated with phos- chinensis (L.) Nus), Hearon et al. (1976) were phate buffer. Disease developed in three of eight unable to transmit witches' broom between I. crenata, six months after inoculation with con- hydrangeas using leafhoppers (Macrosteles fasci- centrated and partially purified virus. frons (Stal.). Causal agent/Relationship : The isolates possessed Causal agent/Relationship : Mycoplasma-like antigenic determinants in common with tobacco organisms were observed in ultra-thin sections of ringspot virus.

38 Reference more, whereas none of 25 healthy plants died, there Waterworth. H.E. and Povish. W.R. (1977). A yellow leafspot was a 56% (14/25) mortality in the tobacco ringspot Ilex crenata caused by tobacco ringspot virus. Pl. Dis. disease of infected stocks. Reptr 61, 104-105.

References Atanasoff. D. (1935). Old and new virus diseases of trees and shrubs. Phytopath. Z. 8, 197-223. JASMINUM-0/eaceae Cane, H. (1720). An account of two observations in gardening, upon the change of colour in grapes and Jessamine. Phil. Trans. See plate 44 (Colour) R. Soc. B. 31, 102-104. Cooper, J.I. and Sweet. J.B. (1976). The detection of viruses with nematode vectors in six woody hosts. Forestry 49, 73-78. Foliage diseases McLean, D.M. (1960). An infectious mosaic of Jasminum. J. Rio Grande Vall. hort. Soc. 14, 187- 188. SYMPTOMS : Yellow rings and blotches. Morton, C.S., Barnett. O.W. and Baxter, L.W. (1977). Damage caused by tobacco ringspot virus to poet's jasmine (Jasminum Distribution : Widespread. officinale). Proc. Southern Nurserymen's Assoc. Res. Cong., Transmission : Cane (1720) reported that yellow 22nd Ann. Rept 111-114. striped leaves developed on a green plant grafted Waterworth, H.E. (1971). Physical properties and host ranges of viruses latent in and mechanically transmitted from jasmine. with a variegated form of Jasminum sp. This very Phytopathology, 61, 228 - 230. early report of graft transmission has subsequently been confirmed (Atanasoff, 1935; McLean, 1960, Waterworth, 1971). A virus was transmitted to "herbaceous hosts" inoculated with sap extracts JUGLANS—Juglandaceae from the yellow blotched leaves of J. officinale L. cv aureo-marmorata Hort. (Cooper and Sweet, See plate 45b/46 (Colour) 1976). Causal agent/Relationship : Although arabis mos- Foliage diseases aic virus was transmitted from and identified serologically in yellow Jasminum foliage, this virus SYMPTOMS : Chlorotic discolourations of leaf laminae isolate systemically infected J. officinale seedlings in the form of yellowish spots, rings and line patterns but did not affect leaf colour during the ensuing accompanied by occasional necrotic flecks or chrome year. yellow blotches on leaves and fruits (Savinoetal.,1976 ; Savino et al., 1977 ; Quacquarelli and Savino, 1977). COMMENTS : Several viruses have been isolated from Symptoms first obvious in U.K. in June ; rarely affecting more than 25% of the leaves on any tree. symptomless Jasminum plants ; tobacco ringspot and cucumber mosaic viruses from J. nudiflorum Lindl., tobacco ringspot and arabis mosaic virus from J. Distribution : Although trees with foliage symp- mesnyi Hance. (J. primulinum Hemsl.). A previously toms seem few, virus infection is widespread in J. undescribed virus, which Waterworth (1971) called regia L. in Southern Italy (Quacquarelli and Savino, jasmine latent virus 1, was transmitted from J. 1977) and in U.K. where incidence parallels fre- odoratissimum L. These viruses were more readily quency of J. regia, being ten times greater in transmitted to "herbaceous hosts" when inoculated southern as compared to northern Britain (Cooper, with petal rather than leaf sap extracts. Waterworth unpublished data). (1971) isolated an aphid-transmissible virus (which he Transmission : In sap from leaves, fresh pollen or provisionally named jasmine mild mosaic) from leaves immature fruits to "herbaceous hosts" and in seed of J. multiflorum Andr. with mild mosaic symptoms. of naturally infected J. regia: the amounts of seed transmission to seedlings being 32% when seed SYMPTOMS : General poor growth associated with was stored at 25°C before germination (Quac- yellow blotches in young foliage plus leaf drop and in quarelli and Savino, 1977). Four to six percent older leaves, necrotic spots and interveinal chlorosis. transmission occurs in Juglans seed stratified Distribution : Affecting J. officinale in South before commercial use in U.K. (Cooper, unpub- Carolina, U.S.A. lished data). In Italy, virus infected seedlings had mild chlorotic mottle symptoms and smaller leaves Transmission : In sap to 'herbaceous hosts'. than healthy (Quacquarelli and Savino, 1977). Causal agent/Relationship : Tobacco ringspot virus Although this was not observed in U.K. 3 year old was associated and, in a brief report without virus infected seedlings were significantly details was said to cause the disease. (Barnett, (P.<0 .01) shorter () and the mean diameter at personal communication in Morton et al, 1977). one third total height was significantly (P-<0 -05) less (4/5) than the dimensions of their healthy COMMENTS : During a six month period, Morton et al, counterparts (Cooper, unpublished data). (1977) compared naturally infected and tobacco ringspot free clones of J. officinale and reported that the Causal a ent/Relationshi s : The isolates associated virus-infected plants had fewer flowers, shorter stems in Italy with the different syndromes and tentatively (50% of controls) and inferior root systems. Further- named walnut ringspot and walnut yellow mosaic

39 Plate oba—V,alnur tor c h osease-

viruses (Saono ei al. 1976) differed slightly one Don-Houton: O•despreae in the eastern USA from another but possessed antigenic determinants (Hutchins and 'Wester, 1947: Miller and Tnorep- in common with cherry' leaf run viiLltr coiares sod 1949) iot re;8.Hrteo from Europe. The species (Savino et al_ 1977). Cherry leaf roil virus Is •dlales most se,ereO affected rDii; the d.sesse are : 8kgra L. have been obtained from cymptoreless xyamats J. cif/ere:9 L. eri.1 J. ales:a/c/feed Maxim. U.K. (Cooper, unpubeshed data) and Italy (Cade- Transmission : 58 bark patch nraft•ng between J. quarelli and Savino, 1977) Indeed, tnis 3 me rule ar7r3 am• C. .Hys,t)okirana airhiieagri idther than the exdephun Because seedling J rekho syrnprOms too< DiEarS or rniiirri riDst,Dve in the detialc healtey c Lidded and s,:steethaay infected wm a e.a Hi d Con inn and Mc .Xak. 1974). jLite emend leaf roll \.:ruk fallen t8 dese foliage symptoms during tvivo suosequent 8easol ) Ca I :HeWr:Dr13h1b. Seliskar (1973) re- (Conner ,ahleublohed data) possihe thEt ott st MCO treveia:eDi hi electron attents thah cherry leaf roH csea ma8 he Lathcht the feliacie swmotomul aceasen but nl hea lily trees There has been no

COMMENTS - In hiu Jana, a omilar svnsr line parrem) was rood but hut sod ed i hest . 1958)

(-.) I HERS - (draft incompatiboty of untested aietiolug). 8dowog as a black line at the union behAeen Dr\s un C.OrjrJ L. routstocks and hhImmatinj ni tos death pf bank and me trees iAias nuted in the U S A ei of Pdh 7) and in the II K (Glenn 1966)

Stem disease tiHHJ In C3- Pi Dr, Pt-orr 33 405 SYMPTOMS: Walnut bunch. Bunched. wiry shouts, dwarfed and chlorotic leaves diminished yield of nuts and of veneer quaety timber and premature death.

40 LABURNUM—Leguminosae

sditum Bettint. aria Rutide. se• 1938) and C /fools trrauTara L. Bair, 1917) mosaic 5i55 was identified fallowing tirds3itsssisTi nerbacepas masts Tioisuiated wit* Porn L eiendr. On L. anesii3rotiiies racitstidcKs (i:poser _ Sweet, 1976), Leases sit zne fdrmer, wnicti was stunted. •ere uniTirotc.. Furthermore. me terminal bad3 •ere dead and some main siiistits 83ere dying bacb. Hsetef (1976) CO315i5 tently assacitlted Fusarutin espenaceern LAVANDULA—Labiatae (Corda cx Fri.) Sacc . iwith tne bud dean symptom and showed that Psis fungus caused pud death Foliage disease A graft transmissible chlorosis of L. anag/roicies. L. aLoinum cy at:ream and C. hirsutus wiracii seat •rli Fri - SYMOTil)MS Mosaic. !sae were more Or less uniformly chilorotic (sometimes astripuuen Recorded in France affecting Lavan- yeHow) has been associated with two sap transmissihie dula hybrida Rev. (Marchaux and Rougier, 1974). •pu5es, arab s mosaic. and tomato biack ring (ScniineT Transmission In sap to -herbaceous hosts-. Seri, 1962/63, 1968). However L. anagyraideS Caassl agent/Relationship: Unknown but alfalfa niwried 3simptomiess foHawing inocuidtion witn 'TIOS vc riiruS was identified in "'herbaceous hosts- .solateof arabis mosaic virus from L. anagyroices inoculated with sap from affected lavender. (Schmeizer, 1962/63). Sphmeizer was unsuccessful in his attempts to transn8t variegation us Laburnum ticina sap from affected specimens ci Llma am, i1374; Virus de la mDsarriu±?'Ilr, orrun avembn GavenJuia ryorda Roo/

LEYCESTERIA—Capnfoliaceae

aiistot r nac and flec8s Eaee been reported in L. fourIo5a grow.ng in England. Somewhat more necrotic symptoms were observed in Romania (Savu- lesca and Ploaie. 1961, cited in Schmelzer, 1968). The Sr`clunns in England were associated with cucumber mosaic virus (Hollings. 1961a and b).

Refarences M (1961M Voura and Its effect on some ornamental sorobs Naperyra Seedsrn. Glasshouse Grower (1961), 930-931. Moilimas M (1961b). virology. Rep. Glasshouse Crops Res. Inst. T 960 'j 7 —L,,ornam anaoyroides foliage shaNini ahlomlis yelp- Scha-,eizer. K. (1968) Lem. Forst- und Wildgeholze. H : ins oss.ciated earn rbabda]vouslike paMales. Pflorshrra LOrokape edited by M. Klinkowslm vol. 2 part 2. 232-303 Rorlin : Akaomme—Verbag.

41 Cooper, J.I., (1975). Some non-rosaceous trees and shrubs as LIGUSTRUM-Oleaceae hosts to nematode-borne viruses. In Lamberti F.. Taylor, C.E. and Seinhorst, J.W. (Eds). Nematode vectors of plant viruses. Foliage diseases London Plenum Press, 277-278. Hilderbrand, E.M. (1953). Ringspot of privet in Texas. Pl. Dis. SYMPTOMS : Chlorotic chevrons, rings or blotches. Reptr 37. 636. Jankulova, M. and Schmelzer, K. (1974). Erstmaliger Nachweis Distribution : Widespread in Europe and North des Arabis-mosaik-virus in der Volks republik Bulgarien. Arch. America affecting Ligustrum vulgare L. and L. Phytopathol. Er. Pflanzenschutz 10. 283-284. ovalifolium Hass Karl. Kochman, J., Kowalska, H. and Szymanska, B. (1964). Under- suchungen uber Virosen des Flieders (Syringa vulgaris L.) und Transmission : In foliar sap to "herbaceous hosts" des Ligusters (Ligustrurn vulgare L.). Phytopath. Z 51, 333-350. (Kochman et al, 1964 ; Schmelzer, 1962/63; Lovisolo, 0.. Bode, 0. and Volk, J. (1965). Preliminary studies on Smith, 1957 ; Cadman, 1960 ; Cooper, 1975) and the soil transmission of Petunia asteroid mosaic virus (="Petunia" by grafting (Baur, 1907 ; Hildebrand, 1953). strain of Tomato Bushy Stunt Virus). Phytopath. Z. 53. 323-342. Novak. J. (1969). Investigation of virus diseases of lilac. Proc. Causal agent/Relationships : A great many ob- Conf. Czech. Plant Virologists, 6th, Olomouc (1967),1289-293. servations have been made on plants in several Schmelzer. K. (1962/63). Untersuchungen an Viren der Zier und countries showing similar symptoms. There is Wildgeholze 2. Mitteilung : Virosen an Forsythia, Lonicera, therefore some doubt about whether the diseases Ligustrum und Laburnum. Phytopath. Z. 46, 105-138. Schmelzer. K. (1972). Das Kirchenblattroll-virus aus der Birke were in fact the same. Smith (1957) identified (Betula pendula Roth.) Zentbl. Bakt. Parasit Kde Abt. II, 127, 10- cucumber mosaic virus in association with the 12. symptoms in L. vulgare and, although Kochman et Seymour, C. P. (1965). Plant pathology section-Bienn. Rep. al, (1964) did not identify the isolates they obtained, Fla. Dep. Agric. no. 25 1962-1964,124-159. their published data are not incompatible with Smith, K.M. (1957). Textbook of plant virus diseases. 2nd Edition. London : Churchill. having also obtained a cucumovirus. By contrast, arabis mosaic virus has been identified by Schmel- zer (1962/63), Cadman (1960), Jankulova and Schmelzer (1974), Cooper (1975) and Brunt and LONICERA-Caprifoliaceae Thomas (1975). Lihnell (1951) reported the transmission of cucumber mosaic virus to 'herbaceous hosts' inoculated with sap SYMPTOMS : Bright yellow rings and spots with from weakly growing plants of Lonicera pericylmenum chlorotic rings and, less frequently, depressed or L. having distorted leaves with ringspot symptoms but necrotic lesions. did not report the effect when this virus was inoculated Distribution : In USA affecting L. lucidum Ait. into healthy plants. In a brief statement. Brunt and Transmission : By grafting to L. lucidum (Plakidas Thomas (1975) noted their detection of a virus they 1959). called 'Ionicera latent' which had particles about Causal agent/Relationship : Not known. 650nm long ; its pathogenicity for honeysuckle was not reported. COMMENTS : Similar syndromes occur in L. vulgare Vein-yellowing which gives plants of L. japonica Thunb. and L.ovalifolium in UK and in L. japonicum Thunb. cv aureo-reticulata horticultural value did not always in the USA. develop when affected tissue was grafted to healthy Several viruses have been isolated following inocula- Lonicera. The plants with vein yellowing did not yield tions of foliar sap to "herbaceous hosts". viruses manually transmissible to "herbaceous hosts" (1) Few details are available but Seymour (1965) (Schmelzer, 1962 /3). However, Sweet (unpublished detected prunus necrotic ringspot virus in L. data) transmitted the disease agent by grafting and japonicum Thunb. frequently isolated CMV from affected plants ;• he did (2) Schmelzer et al, (1969 cited in Schmelzer, not prove that CMV caused the di.sease. 1972) reported cherry leaf roll virus. (3) Tomato bushy stunt virus has been isolated References from roots but not leaves of L. vulgare (Lovis- Brunt, A.A. and Thomas, B.J. (1975). Miscellaneous hardy olo et al, 1965). nursery stock. Rep. Glasshouse Crops Res. Inst., 1974,124. Lihnell, D. (1951). Nagra vardvaxtor for Cucumis-virus I i (4) A virus having slightly flexuous rod-shaped Sverige. Vaxtskyddsnotiser 15, 52-56. particles about 650nm long has been reported Schmelzer, K. (1962/3). Untersuchungen an Viren der Zier und by Brunt and Thomas (1975). Wildgeholze. 2. Mitteilung : Virosen an Forsythia, Lonicera, (5) Novak (1969) suggested that the virus he Ligustrum und Laburnum. Phytopath. Z. 46, 105-138. isolated from L. vulgare was probably tomato black ring.

References LYCIUM-Solanaceae Baur. F. (1907). Uber infektiose chlorosen bei Ligustrum, Laburnum. Fraxinus, Sorbus und Ptelea. Ber. dt. bot. Ges. 25, Foliage disease 410-413. Brunt, A.A. and Thomas, B.J. (1975). Miscellaneous hardy SYMPTOMS : Chlorotic mottling with some necrosis. nursery stock. Rep. Glasshouse Crops Res. Inst., 1974,124. Cadman. C.H. (1960). Viruses with nematodes as vectors. Distribution : East Germany (Schmelzer and Rep. Scott. hort. Res. Inst. 1960-1,54. Schmidt, 1968) and Bulgaria (Kovachevsky 1965 ;

42 cited in Schmelzer, 1968) affecting Lycium cucumovirus group was identified but not proven halimifolium Mill. to cause the associated disease (Plese and Milicic, 1973). Transmission : In sap to "herbaceous hosts".

Causal agent/Relationship: Cucumber mosaic References virus was identified and reproduced the syndrome Edwardson. J.R. (1966). Cylindrical inclusions in the cytoplasm when reintroduced into seedlings (Schmelzer and of leaves infected with tobacco etch virus. Science N.Y. 153, Schmidt, 1968). 883-884. Edwardson, J.R. (1974). Some properties of the potato virus Y group. (Florida Agricultural Experiment Stations Monograph COMMENTS : Schmelzer (1974) reported that L. no. 4). halimifolium was susceptible to experimental infection Plese, and Milicic, D. (1973). Two viruses isolated from Maclura with elm mottle virus. pomifera. Phytopath. Z. 77. 178-183. Plese, N. and Stefanac, Z. (1976). Some properties of Maclura mosaic virus a member of the potyvirus group. Mitt. biol. References BundAnst. Ld-u. Forstw. 170, 47-50. Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2, 232-303. Berlin : Akademie—Verlag. Schmelzer, K. (1974). Untersuchungen an Viren der Zier- und Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- gea und Philadelphus sowie Viren and Virosen an Rhamnus, MAGNOLIA—Magnoliaceae Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllurn, Celastrus. Staphylea und Crambe. Zbl. Bakt. Parasit Kde 129. 139-168. Foliage disease Schmelzer, K. and Schmidt, H.E. (1968). Untersuchungen an Viren der Zier-und Wildegeholze. 6, Mitteilung : Erganzende Befunde an Caryopterissowie Virosen an Philadelphus, Aristolo- SYMPTOMS : Chlorotic line patterns. chin, Buddleja, Lycium und Aesculus Phytopath. Z. 62, 105-126. Distribution : In East Germany and Czechoslovakia affecting Magnolia sp. (Schmelzer and Schmelzer, 1968). MACLURA—Moraceae Transmission : Mechanically in magnolia leaf sap to "herbaceous hosts". Foliage diseases Causal agent/Relationship : The isolated virus was identified with cucumber mosaic virus but this was SYMPTOMS : Yellow mosaic associated with foliar not proven to cause the associated disease. distortion and interveinal yellowing which in turn causes local tissue translucency, is more obvious in Reference spring than during summer periods of high temperature Schmelzer, K. and Schmelzer, A. (1968). Virus befall an Magnolien (Plese and Milicic, 1973). (Magnolia spp.). Acta phytopathol. Acad. Sci. Hung. 3, 411-413. Distribution : Only known from Yugoslavia affecting Maclura pomifera (Raf.) Robinson. MORUS—Moraceae Transmission : Mechanically, to infect "herbaceous hosts" inoculated with sap from young or old Foliage disease leaves or from bark and from diseased to healthy Maclura seedlings by aphids (Myzus persicae SYMPTOMS : Mosaic and (at temperatures below Sulz.) it was non-persistent (Plese and Stefanac, 30°C) enations (lshiie and Kawakami, 1966). 1976). Distribution : Japan. Causal agent/Relationship : Cylindrical and pin- Transmission : In sap to "herbaceous hosts". wheel inclusions, characteristic of potyviruses (Edwardson, 1966 1974) were seen when infected Causal agent/Relationship : Not known. A virus Maclura leaf tissue was examined in an electron having spherical particles c 30nm in diameter and microscope. However, the flexuous rod-shaped nematode (Longidorus martini Memy) vectors virus-like particles seen were shorter (600— (Yagita and Komoro, 1972) was identified but did 650nm) than those typical of potyviruses (Plese not cause symptoms in experimentally infected and Stefanac, 1976). mulberries (Tsuchizaki et al, 1971). COMMENTS : Virus-like particles having flexuous rod- SYMPTOMS : In summer, some leaves have chlorotic shaped particles of undescribed relationships were ringspots up to 2cm (diameter), others have yellow- observed with the aid of an electron microscope in white spots and curved line patterns. diseased Morus, but their role in the pathology of Distribution : Only known from Yugoslavia affec- mosaic disease remains obscure. ting M. pomifera. At temperatures of 30°C (but not below), lshiie and Transmission : Mechanically in leaf sap to infect Kawakami (1966) resolved a second component of the "herbaceous hosts". mosaic syndrome, the production of filliform leaves Causal agent/Relationship : On the basis of sero- with mosaic. The cause is unknown. A mosaic disease logical tests and host symptoms, a member of the of Morus indica L. was recorded in India and was re- 43 portedly transmitted by two aphid genera (Chatterjee Causal agent/Relationship : Not known ; there are and Raychaudhuri, 1965). some similarities with diseases associated with A distinct agent associated in India with a yellowing mycoplasma-like organisms. of leaf veins was graft transmissible and has been suggested but not proved to have whitefly vectors (Ray- Reference chaudhuri et al, 1961). Raychaudhuri, S.P. (1952). Bayberry yellows. Phytopathology 42, 17. Stem disease

SYMPTOMS : Witches' broom (mulberry dwarf.) NAN D INA—Berberidaceae Branch proliferation, leaf chlorosis and bud precocity. Distribution : Japan. Foliage disease Transmission : By grafting and by Hishimonus SYMPTOMS : Reddening of petals and some (but not sellatus Uhler, leaf-hoppers (Ishiie and Matsumo, all) leaves seen in spring, although infected leaves 1971 a and b). tended to recover in hot summer weather. Additional Causal agent/Relationship : MLO observed in symptOms included distortion and narrowing of leaf ultra-thin sections of phloem parenchyma cells laminae, diminished flower number and poor fruit set (Doi, et al, 1967) : remission of symptoms followed (Barnett and Baxter, 1973a and b). tetracycline therapy (lshiie and Matsumo, 1971 a Distribution : In South Carolina and Mississippi. and b). USA affecting Nandina domesticaThunb. (Brierley and Smith, 1960 ; Barnett and Baxter, 1973a and b). References Chatterjee, S.N. and Raychaudhuri, S.P. (1965). A note on aphid Transmission : In sap to "herbaceous hosts" but no transmission of mosaic disease of mulberry. Indian Phytopath. natural spread noted and not seed borne to seventy 18, 319-320. seedlings observed. Doi, Y., Teranaka, M., Yora, K. and Asuyama H. (1967). Myco- plasma-PLT group-like microorganisms found in the phloem Causal agent/Relationship : Cucumber mosaic elements of plants infected with mulberry dwarf, potato witches' virus was identified and caused interveinal redden- broom, aster yellows or Paulownia witches' broom. Ann. phyto- ing and other symptoms similar to those seen in pathol. Soc. Japan 33, 259-266. lshiie, T. and Kawakami, F. (1966). (Effect of temperature on the naturally infected plants. appearance of symptoms of Mulberry mosaic disease. II. Com- parative observations on enations and filiform of Mulberry plants). References Ann. phytopath. Soc. Japan 32, 210-214. Barnett, O.W. and Baxter, L.W. (1973a). Cucumber mosaic virus lshiie, T. and Matsumo, M. (1971a). (Studies on the transmission in Nandina and other ornamentals. Proc. I. Symp. Virus of Mulberry dwarf disease by a vector leaf hopper, Hishimonus Diseases of Ornamentals, 3rd Sept. 1972.65-74. sellatus Uhler. I. On the acquisition of the causal agent in non- Barnett, O.W. and Baxter. L.W. (1973b). Cucumber mosaic virus virilifersous vector). Ann. phytopath. Soc. Japan 37, 136-140. on Nandina domestica in South Carolina. PI. Dis. Reptr 57, 917— lshiie, T. and Matsumo. M. (1971b). (Studies on the transmission 920. of Mulberry dwarf disease by a vector leafhopper. Hishimonus Brierley, P. and Smith, F.F. (1960). Cucumber mosaic virus in sellatus Uhler. II. On the inoculation of the causal agent by Nandina domestica. Phytopathology 50, 569. viriliferous vector). Ann. phytopath. Soc. Japan 37, 141-146. Raychaudhuri, S.P. Chatterjee. S.N. and Dhar, H.K. (1961). Preliminary note on the occurrence of a yellow-net vein disease of Mulberry. Indian Phytopath., 14, 94-95. PAS S I FLORA—Passifloraceae Tsuchizaki, T., Hibino, H. and Saito. Y. (1971). Mulberry ringspot virus isolated from mulberry showing ringspot symptom. Ann. Cucumber mosaic virus was detected in one plant of Phytopath. Soc. Japan, 37, 266-271. Passiflora caerulea L. showing chlorosis, curling and Yagita, H. and Komoro, Y. (1972). Transmission of mulberry leaf deformation (Zschau, 1964) but the virus may not ringspot virus by Longidorus martini Memy. Ann. Phytopath. Soc. Japan. 38, 275-283. cause these symptoms. The only other virus identified from P. caerulea growing in Europe has not been associated with symptoms and was in the first instance MY R I CA—Myricaceae detected when infected leaves were examined with an electron microscope (Schnepf and Brandes, 1961 /62). Stem disease Passiflora latent virus is readily transmitted to "herbaceous hosts" inoculated mechanically with foliar or SYMPTOMS : Leaf yellowing stunting and a "witches' petal sap but not by aphids (Myzus persicae: Brandes broom- appearance. and Wetter, 1963/64). Passiflora spp. (eg. P. edulis Sims) grown for fruit in Distribution : Recorded in New Jersey, USA affec- semi-tropical regions are liable to infection with ting Myrica carolinensis Mill. (Raychaudhuri, cucumber mosaic and/or passion fruit woodiness 1952). viruses (see Taylor and Greber, 1973 and others cited Transmission : By grafting (but not in sap) also by therein.) dodder (Cuscuta campestris) to Vinca sp. causing "yellows" symptoms and flower malformation. References The leaf hopper Macrosteles divisus Uhler failed to Brandes, J. and Wetter. C. (1963/4). Untersuchungen uber transmit the disease to "herbaceous hosts". Eigenschaften und Verwandtschaftsbeziehungen des Latenten

44 Pass/ flora-virus (Passiflora latent virus). Phytopath. Z. 49, 61-70. PHILADELPHUS-Saxifragaceae Schnepf, E. and Brandes, J. (1961/62). Uber ein Virus aus Passiflora sp. Phytopath. Z. 43, 102-105. Taylor, R.H. and Greber, FI.S. (1973). Passion fruit woodiness Foliage diseases virus. C.M.I./A.A.B. Descr, Plant Viruses. no. 122. Zschau, K. (1964). Eine Mosaikkrankheit an Passiflora caerulea L. SYMPTOMS : Chlorotic mottle or chevron patterns on NachrBI. dt. PflSchutzdienst. Berl. 18, 16. leaves which, in some instances, were also twisted. Distribution : In East Germany affecting P. falconeri Sarg. PAU LOWN IA-Scrophulariaceae Transmission : In sap to "herbaceous hosts". Causal agent/Relationship : Cucumber mosaic Foliage disease virus was identified in affected plants but not proved to be the cause of the disease (Schmelzer, SYMPTOMS : Deforming mosaic, vein banding, chlor- 1970). otic ringspot or oak-leaf symptoms (Horvath, 1973) 44% diminishment in height and 49% decrease in SYMPTOMS : Whitish rings/arcs/mottle or oak leaf diameter growth as compared with healthy (Schmelzer, patterns. 1969). Distribution : In East Germany affecting Philadel- Distribution : Hungary affecting P. tomentosa. phus sp. (Schmelzer and Schmidt, 1968). Transmission : In sap to "herbaceous hosts". Transmission : In sap to "herbaceous hosts". Causal agent/Relationships : Cucumber mosaic Causal agent/Relationship : Alfalfa mosaic virus virus (CMV) identified and in a series of tests was isolated and identified and shown to cause the Schmelzer (1969) inoculated seedlings of P. syndrome (Schmelzer, 1970). tomentosa with CMV to obtain systemic infection and chlorotic symptOms although not the full SYMPTOMS : Like those of white mottling associated range reported by Horvath (1973). with lucerne mosaic virus. Light green-dark green mosaic with blistering and increased indentations of the COM MENT : Schmelzer (1974) reported that Paul- margins of leaves on some (but not all) branches. ownia tomentosa was susceptible to experimental Distribution : In East Germany affecting Philadel- infection with elm mottle virus. phus spp. (unspecified). Stem disease Transmission : In sap to "herbaceous hosts". Causal agent/Relationship : Isolates from Philadel- SYMPTOMS : Axillary buds and shoots were pre- phus were identified with elm mottle virus (Schmel- cocious and grew almost throughout the year, branches zer, 1974) but although one of these isolates was tended to be erect, leaves were thin narrow chlorotic inoculated and infected eighty two species and tended to fall preMaturely. Root growth tended to (seventy four systemically) in twenty six families, be poor and affected trees died within a few years of Philadelphus was not one of these and the relation- symptoms first showing. ship of the virus with the disease therefore remains Distribution : Widespread in South East Asia unproven. affecting Paulownia tomentosa (Thu nb.) Steud. and P. fortunei Hensl. (Tokushige, 1951). References Schmelzer, K. (1970). Untersuchungen an Viren der Zier- und Transmission : Root or stem grafting. Wildgeholze. 7. Mitteilung : Weitere Befunde an Buddleja, Causal agent/Relationships : MLO associated with Viburnum, Caryopteris und Philadelphus sowie Viren an Leyces- teria, Chionanthus, Ribes, Hydrangea, Syringa, Spiraea und the syndrome (Doi et al., 1967). Catalpa. Phytopath. Z. 67, 285-326. Schmelzer, K. (1974). Untersuchungen an Viren der Zier- und References Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- Doi, Y., Teranaka. M.. Yora. K. and Asuyama, H. (1967). Myco- gea und Philadelphus sowie Viren and Virosen an Rharnnus, plasma- or PLT group-like microorganisms found in the phloem Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllurn, Celastrus, elements of plants infected with mulberry dwarf, potato witches' Staphylea und Crambe. Zbl. Bakt. Parasit Kde 129 Abt 1 1 1 , 39-1 68 broom, aster yellows or Paulownia witches' broom. Ann. phyto- Schmelzer, K. and Schmidt, H.E. (1968). Untersuchungen ari pathol. Soc. Japan 33, 259-266. Viren der Zier- und Wildegeholze. 6, Mitteilung : Erganzende Horvath, J. (1973). A mosaic, vein banding and chlorotic ring- Befunde an Caryopteris sowie Virosen an Philadelphus, Aristol- spot disease of Paulownia caused by cucumber mosaic virus. ochia . B uddleja, Lyciurn und Aesculus. Phytopath. Z. 62, 105-126 Phytopath. Z. 76, 182-185. Schmelzer, K. (1969). Virus infektionen an Paulownia tomentosa (Thunb.) Steud. Acta. phytopathol. Acad. Sci. Hung. 4, 321- 326. PITTOSPORIUM-Pittosporaceae Schmelzer, K. (1974). Untersuchungen an Viren der Zier- und Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- Foliage disease gea und Philadelphus sowie Viren and Virosen an Rhamnus, Centaurea, Galvezia, Cistus, Forestiera. Abeliophyllum, Celastrus, SYMPTOMS : The smaller downward rolling leaves of Staphylea und Crambe. Zbl. Bakt. Parasit Kde 129, 139-168. Tokushige, Y. (1951). Witches' broom of Paulownia tomentosa diseased plants have vein yellowing which mainly L. J. Fac. Agric. Kyushu, Univ. 10, 45-67. affects lateral veins (Plavsic-Banjac et al. 1976).

45 These symptoms are less obvious in summer than in POPULUS—Salicaceae other seasons—possibly an effect of high temperature (Corte, 1957). See plate 48 (Colour) Distribution : Affecting P. tobira (Thunb.) Ait. in Italy (Corte, 1957) and Yugoslavia (Horvath, Foliage disease 1973 ; Plavsic-Banjac et al. 1976). Transmission : By grafting diseased and healthy SYMPTOMS : Mosaic. Yellow spots which tend to P. tobira (Horvath, 1973) but apparently not by extend along the fine leaf veins (astroid spotting) seeds, aphids or mites (Corte, 1957). typically appearing first in the oldest fully expanded Causal agent/Relationship : Symptoms in P. tobira leaves in late spring. Diminishment in height and linked to rhabdovirus-like particles, measuring diameter growth may occur during the first year or two 245 x 18nm and associated with inner nuclear after planting but the effect, which is greater in some membranes of affected cells. clones (eg. P. x euramericana cv Eugenei 15 to 20%) than others (eg. P. x euramericana cv Gelrica—no COMMENTS : Sparse evidence suggests that vein significant decrease) is probably not maintained for yellowing is distinct from (a) graft-transmissible more than a year or two (Navratil, 1963; van der variegation recorded in P. tobira in France (Carriere, Meiden, 1964, M.il,inko and Schmelzer, 1968, Mackay 1887) and the USA (Brierley, 1944) ; (b) mosaic of and Beaton, 1969 ; Biddle and Tinsley, 1971b). P. daphniphylloides Hayata noted by Milbrath (1940). Specific gravity and the strength of branch wood (buttwood was not tested) can also be adversely Stem disease affected (Biddle and Tinsley, 1971b). High temperatures tend to mask symptoms in foliage (Bertranet SYMPTOMS : (a) Necrosis of outer bark which is and Taris, 1971). shed. Distribution : In Bulgaria (Atanasoff, 1935), Yugo- (b) Death of branches. slavia (Perisic, 1951), Netherlands (Berg, 1962), Both symptoms have been associated with the following Poland (Benben, 1957), Denmark (Kristensen, foliage defects ; chlorotic blotches, ringspots, oak- 1960), Italy (Corte, 1960), West Germany (Zycha, leaf or watermark symptoms. 1961 ; Brandes, 1963), Czechoslovakia (Blattny Distribution : Affecting P. tobira, P. crassifolium et al., 1962 ; cited in Berg, 1964), East Germany Solander and P. viridiflorum Sims and "variegated" (Schmelzer, 1964) and the Georgian SSR (Navra - P. tobira (Thomas and Baker, 1947). til, 1965). Berg (1964) cited authorities for the Transmission : By grafting affected P. crassifolium occurrence of the disease in all areas where poplars or P. tobira to P. tobira. No transmission through are grown commercially except South Africa and seed observed (Thomas and Baker, 1947). South America and reported that almost all clones of the Aigerios Duby and Tacamahaca Spach. Causal agent/Relationship Unknown. sections (Anon, 1958) of the genus Populus were susceptible to the diseases ; clones of the Turanga Bge., Leuce Duby and Leucoides Spach. sections COMMENTS : Slight swellings on dwarf stems with were not. Although Brunt et al. (1976) reported roughened bark have been noticed in Florida in the isolation of poplar mosaic virus from a hybrid vegetatively propagated planting stock (Alfieri and P.tremuloidesx P.tremula, the tree in question was Seymour, 1970). a P. euramericana hybrid (Brunt, personal communication).

Transmission : By grafting and in sap to herbaceous References hosts (Berg, 1962 ; 1964). There is no unequivocal Alfieri, S.A. and Seymour, C.P. (1970). Rough bark of Pittosporum evidence that the disease spreads from tree to tree. tobira Ait. in Florida. Proc. Fla hort. Soc., 83rd, 438-440. In poplar, the virus was not seed or pollen borne Brierley, P. (1944). Viruses described primarily on ornamental or miscellaneous hosts. PI. Dis. Reptr, 150 Suppl. 410-482. (Cooper, 1976) and was not experimentally trans- (mimeographed). mitted by dodder (Cuscuta californica Choisy or Carriere, E.A. (1887). Influence du greffon sur le sujet. Revue C. subinclusa Dur. Hilg. ; Schmelzer, 1966). Aphids hort. 59, 58-59. have been tried as vectors but the following did not Corte, A. (1957). Una nuova virosi del Pittosporum Riv.Ortofloro- transmit the disease, fruttic. Ital. 41, 197-202. Chaitophorus versicolour C. L. Horvath, J. (1973). A mosaic, vein banding and chlorotic ring - Koch, Pterocomma populea Kitb., Myzus persicae spot disease of Paulownia caused by cucumber mosaic virus. S ulz., Aphis fabae, Aphis cracivora Koch. Phytopath. Z. 76, 182-185. Chaitophorus leucomelas Koch. Macrosiphum Milbrath, D.G. (1940). Probable virus disease of Pittosporum euphorbiae (Thom.) and Hyperomyzus lactucae daphniPhylloides. Mon. Bull. Calif. Dep. Agric. L. 29, 158-159. (Berg, 1964; Blattny, 1965; Schmelzer, 1966 ; Playsic-Banjac, B., Milicic, D. and Eric, Z. (1976). Rhabdovirus in Pittosporum tobira plants suffering from vein yellowing disease. Boccardo, et al., 1973 ; Cooper unpublished data). Phytopath Z. 86, 225-232. Eriophyid mites of the genus Acutops did not Thomas, H.E. and Baker, K.F. (1947). A rough bark disease of transmit the agent between poplars (Cooper, 1976) Pittosporum tobira. Phytopathology 37, 192-194. and experiments described by Berg (1964)

46 indicated that pruning tools did not carry the disease Tomato black ring, tobacco rattle, arabis mosaic and agent. tobacco necrosis viruses were detected in roots but Causal agent/Relationships : Different workers, not leaves of P. x euramericana cv 1-78 and Robusta using phenotypically and genotypically disting- within one year of planting in soil infested with these uishable sources have identified their isolates as viruses (Cooper and Sweet, 1976). poplar mosaic virus having flexuous rod-shaped particles with modal lengths ranging from 626nm OTHER : In a brief report Hibben et al. (1977) reported to 735nm (Berg, 1962). Other data (Brcak and the isolation of tobacco necrosis virus from 'deterior- Blattny, 1962 ; Brandes, 1963; Biddle and Tinsley, ating' clones of Populus tremuloides Mich. in the U.S.A. 1971a Kraus, 1973 ; Atkinson and Cooper, 1976 ; Furthermore, Berbee et al. (1976) briefly noted the Brunt et al, 1976. Luisoni et al, 1976) strengthens detection of a potyvirus-like agent from five Aigerios the possibility that poplar mosaic virus has proper- clones and from a 'deteriorating' aspen. ties in common with members of the carlavirus group although no serological relationship to References seven members of this group was detected by Berg Anon. (1958). Poplars in forestry and land use. F.A.O. For. (1964). Berg also failed to detect antigenic re- Forest Prod. Stud. no. 12. lationship between poplar mosaic virus and the Atanasoff, D. (1935). Old and new virus diseases of trees and shrubs. Phytopath. Z. 8. 197-223. type member of the potex virus group and four poty Atkinson, M.A. and Cooper, J.I. (1976). Ultrastructural changes viruses. in leaf cells of poplar naturally infected with poplar mosaic virus. Ann. appl. Biol. 83. 395-398. Benben, K. (1957). Badania nad chorobami topol w Polsce COMMENTS : A great many different symptoms have wywolanyoni przez ozynniki organiczne. Roczn. Nauk. les. 19, 63-122. been ascribed (often with little justification) to poplar Berbee, J.G.. Omuemu, J.0., Martin, R.R. and Castello, J.D. mosaic disease. For example, Blattny (1965) suggested (1976). Detection and elimination of viruses in poplars. p. 85-91. that the disease could be characterized by diminished In Intensive plantation culture : five years research. U.S.D.A. For. rooting capacity and petiole necrosis and a group of Serv. Gen. Tech. Rep. NC-21. more than seven symptoms ; vein necrosis, top necrosis, Berg, T.M. (1962). Some characteristics of a virus occurring in Nature. Lond. 194, 1302-1303. premature leaf fall, tumour formation, stem cracking. poplars. Berg, T.M. (1964). Studies on poplar mosaic virus and its Furthermore, increased flexibility of lower branches relation to the host. Meded. LandbHoogesch. Wageningen 64, were recognized in P. deltoides Marsh cv. angulata and (11). ascribed to poplar mosaic (Castellani, 1966). Unfort- Bertranet, Y. and Taris, B. (1971). The present state of knowledge unately Kochs postulates have not been even partially of the Poplar mosaic virus and its incidence in cultivated Poplars. 54-64. satisfied for all of these. Bull. Sery. Cult. Er Etudes Peuplier et Saule. Biddle, P.G. and Tinsley, T.W. (1971a). Poplar mosaic virus in The necrotic leaf spotting disease affecting P. tremu- Great Britain. New Phytol. 70, 61-66. loides Michx. in Canada (Boyer, 1962), and in Eastern Biddle, P.G. and Tinsley, T.W. (1971b). Some effects of poplar Europe, where P. canescens (Ait.) Sm. and P. alba L. mosaic virus on the growth of poplar trees. New Phytol. 70, 67- are reported to have symptoms (Blattny,1965), is prob- 75. ably not associated with poplar mosaic virus as was Blattny, C. (1965). Dalsi zprairy o mozaice topolu (Further in- at first thought. Although an agent was reportedly formation on poplar mosaic. Lesn. Cas. 11. 637-648. Boccardo, G., Luisoni, E. and Lovisolo, 0. (1973). Character- transmissible in sap from P. tremuloides, (Boyer, 1962 ization of an Italian isolate of poplar mosaic virus. International detected infection in one of eight suspects), in seed Congress of Plant Pathology, 2nd Abstract 928. (Boyer and Navratil, 1970), by budding (seven of Boyer, M.G. (1962). A leaf spotting disease of hybrid and native ten attempts) and by insects (Boyer, 1962 ; two of aspen. Can. J. Bot. 40, 1237-1242. three attempts), electron microscopic examination Boyer, M.G. and Navratil, S. (1970). Some aspects of transmission and electron microscopy of necrotic leaf spot of aspen. of diseased leaves, extracts and exudates did not Can. J. Bot. 48, 1141-1145. reveal virus-like particles. Indeed, despite the fact Brandes, J. (1963). Elecktrone nmikroskopische Untersuchung that sap from affected aspen leaves passed through eines Pappelvirus. Phytopath. Z. 47, 84-89. a bacteria-retaining filter and rubbed onto primary Brcak, J. and Blattny, C. (1962). Electron microscopic investiga- leaves of Vigna sinensis Endl. cv Black Eye caused tion of poplar mosaic. Phytopathology 52, 954-955. Brunt, A.A., Stace-Smith, R. and Leung, E. (1976). Cytological red brown lesions to develop during three to six evidence supporting the inclusion of poplar mosaic virus in the days (Boyer and Navratil, 1970), the virus aetiology of carlavirus group of plant viruses. Intervirology, 7, 303-308. the syndrome will be more plausible if transmission by Cash, E.K. and Waterman, A.M. (1957). A new species of grafting between aspens can be achieved in conditions Plagiostoma associated with a leaf disease of hybrid aspens. when the uninoculated control plants do not show Mycologia 49, 756-760. Castellani, E. (1966). Report on two little-known poplar diseases. "chlorotic symptoms not verified as necrotic leaf spot" In : Breeding pest-resistant trees, edited by H.D. Gerhold et al, (Boyer and Navratil, 1970). Boyer (1962) and Hepting 86-96. Oxford : Pergamon. (Proc. N.A.T.O. N.S.F. Symp Pa St. (1971) both commented on the macroscopic similarities Univ. 1964). between necrotic leaf spotting in aspens and the dis- Cooper, J.I. (1976). Virus diseases of forest and woodland trees ease shown to be caused by the fungus. Plagiostoma and shrubs. p. 26-27. Annual Report Commonwealth Forestry Institute, Oxford, 1975-76. populi Cash and Waterman (Cash and Waterman, 1957) Cooper, J.I. and Sweet, J.B. (1976). The detection of viruses but it seems unlikely that this is the cause of symptoms with nematode vectors in six woody hosts. Forestry 49, 73-78. observed by Boyer because he reported that no evidence Corte, A. (1960). II mosaico del Pioppo. Monti Boschii 11, of fungi was found in the leaf tissues he examined. 127-130.

47 Hepting, G.H. (1971). Diseases of forest and shade trees of the Schmelzer, K. and Stahl, P. (1972). Zur serologischen Nachweis- United States. Agric. Handb. U.S. Dep. Agric. no. 386. barkeit des Arabismosaik-virus in Ptelea trifoliata L. Acta. phyto- Hibben, C.R., Reece, J. and Bozarth, R.F. (1977). The identifica- pathol. Acad. Sci. Hung. 7, 221-228. tion of tobacco necrosis virus in deteriorating clones of aspen. Proc. AM. Phytopath. Soc. 4, 83. Kraus, H. (1973). Vergleichende Untersuchungen uber ein deutches und ein italienisches Isolate des Pappelmosaikvirus. Wissenschaftliche Prufung fur das Lehramt an Gyrnnasien. PYRACANTHA-Rosaceae Botanischen Institut der Universitat des Saarlandes, Saarbruken. Kristensen, H.R. (1960). Virus sygdomme hos Forstplanter Using the technique of double budding, Sweet (1974) (Virus diseases of forest species). Dansk Skovforen. Tidsskr. 45, observed yellow flecking in leaves of Malus sylvestris 155-166. (M. pumila, Miller cv sylvestris) cv Lord Lambourne (on Luisoni, E., Boccardo, G. and Milne, R.G. (1976). Purification M. sylvestris cv Tremlett's Bitter rootstocks) inoculated and some properties of an Italian isolate of poplar mosaic virus. Phytopath. Z.. 85. 65-73. with symptomless Pyracantha rogersiana Chittenden MacKay, A.G. and Beaton, A. (1969). Preliminary report on cv Roger Red. Similar symptoms in Lord Lambourne plantation trials to assess the effects of poplar mosaic virus on the have been associated with apple mosaic virus (Fulton, growth of some poplar cultivars. Vienna :. F.A.O. International 1972). Poplar Commission Disease Working Party. Meiden, H.A. van der (1964). Virus bij populier (Virus of poplars). References Ned. BoschbTijdschr. 36. 269. Fulton, R.W. (1972). Apple mosaic virus. Milinko, I. and Schmelzer, K. (1968). Some new statements on C.M.LIA.A.B. Descr. Plant Viruses no. 83,4 pp. distribution and harmfulness of black locust mosaic in Hungary. Sweet, J. B. (1974). Virus infections of woody rosaceous orna- Acta Phytopathol. Acad. Sci. Hung. 3, 23-29. mentals. M.Sc. Thesis, University of Bath. Navratil, S. (1963). Prispevek k posnani virove mosaiky topolu. (A contribution to the knowledge of the virus mosaic disease of poplars). Lesn. Cas. 9, 1125-1134. Navratil, S. (1965). A contribution to the pathophysiology of host plant on the model of poplar virus mosaic. Zast. Bilja 16, QUERCUS-Fagaceae 517-522. Perisic, M. (1951). Nova virusna bolest na Knadsko j Topoli kod. nas. (A new virus disease of Canadian poplar in Yugoslavia). Foliage diseases Sumarstvo 4, 522. Schmelzer, K. (1964). Notizen uber die Mosaikkrankheit der SYMPTOMS : Chlorotic vein banding or ringspot Pappel. Arch. Forstw. 13, 787-798. symptoms associated with progressive dieback. Schmelzer, K. (1966). Untersuchungen an Viren der Zier- und Wildgeholze. 5. Mitteilung : Virosen an Populus und Sambucus. Distribution : Arkansas, USA, affecting Quercus Phytopath. Z. 55, 317-351. marilandica Muench. (Barnett, 1971) and Q. Zycha, H. (1961). F.A.O. Commission Internationale du Peuplier. velutina Lam. (Kim and Fulton, 1973). Journal de Liaison du Groupe de Travail de Pathologie No. 2. (mimeographed). Transmission : By grafting but not in sap. Causal agent/Relationship : Not known ; Kim and Fulton (1973) resolved virus-like flexuous rod- shaped particles of unspecified length in sectioned PTELEA-Rutaceae leaf tissue viewed with an electron microscope.

A leaf variegation of yellow colour detected in Ptelea SYMPTOMS : Yellowing, rosetting, necrotic spotting trifoliate L. cv "fol variegatis" was reported graft trans- and premature breaking of dormancy. missible by Baur (1907) but although the effect was Distribution : In USA (California) affecting Quercus sought after for horticultural purposes it was not until agrifolia Nee. and Q. phellos L. and Lithocarpus 1962 that sap transmission tests from the affected densifolia (possibly L. densiflorus Rehd.). plants were tried (Uschdraweit cited in Schmelzer, Transmission : Mechanically in partially purified 1962/63). A virus transmitted from P. trifoliate was foliage extracts but very infrequently (Yarwood tentatively identified as arabis mosaic but was not and Hecht-Poiner, 1970; Neinhaus and Yarwood, inoculated back to healthy Ptelea spp. (Schmelzer, 1972). 1962/1963). Subsequent tests allowed identification Causal agent/Relationship : Rod-shaped virus- of this isolate with cherry leaf roll virus (Schmelzer, like particles resembling those of tobacco mosaic 1972) but other work (Schmelzer and Stahl, 1972) were detected with an electron microscope in showed that arabis mosaic virus may also be detected plants with symptoms but also in a range of in variegated P. trifoliate. symptomless Quercus spp.

References Baur, F. (1907). Uber infektiose chlorosen bei Ligustrum, COMMENTS : It has been proposed that the mildew Laburnum, Fraxinus. Sorbus und Ptelea. Ber. dt. bot. Ges. 25, fungus Sphaerotheca lanestris Harkin is a vector of the 410-413. virus because conidia from Quercus induced lesions to Schmelzer. K. (1962/63). Untersuchungen an Viren der Zier- und form on "herbaceous hosts" onto which they were Wildgeholze 3. Mitteilung : Virosen an Robinia, Caryopteris, dusted (Yarwood, 1971). Ptelea und anderen Gattungen. Phytopath. Z. 46. 235-268. Schmelzer, K. (1972). Demonstration of the relationship between Schmelzer, et al., (1966) recognised in Quercus spp. provenances of cherry leaf roll virus and elm mosaic virus. Zbl. three foliage diseases of possible virus aetiology but Bakt. Parasitkde 127 Abt. II, 140-144. the symptoms on which they based their diagnosis did

48 L.Drit ;:ymptLYns ulting frrrrn r SYMPTOMS : Yellow or chlorotic leaf mottle COMMENT: Schmelzer (1974) showed that R. fran- Distribution : In Denmark affecting Q. borealis gula leaf sap mixed with extracts of plants infected with Mich. (syn. Q. rubra, Duroi) (Kristensen, 1963). cucumber mosaic virus did not eliminate infectivity suggesting that an inhibitory property of the sap was not Transmission : By budding to Q. borealis which responsible for the failure to detect sap transmissible subsequently became stunted. infectivity in the naturally affected R. frangula. Causal agent/Relationship : Not known. SYMPTOMS : Chlorotic rings, more obvious on young References than older leaves. Bamett, O.W. (1971). Mosaic of black jack oak. Pl. Dis. Reptr. 55, 411. Distribution : In Italy, affecting Rhamnus fragula. Biddle, P.G. (1968). A study of virus diseases of forest trees. Transmission : In sap to "herbaceous hosts" when D.Phil. Thesis, University of Oxford. Blattny, C. (1964). Contributions to the detection of virus dis- immature leaf or root extracts were used as in- eases in woody plants. Proc. Conf. Czech. Plant Virologists, 5th oculum. Prague. 1962,155-161. Causal agent/Relationship : Alfalfa mosaic virus Horvath, J., Eke, I.. Gal, T. and Dezsery, M. (1975). Demonstra- was identified but not proved to be causing the tion of virus-like particles in sweet chestnut and oak with leaf deformation in Hungary. Z. PfIKrankh. PflPath. PfISchutz. 82, symptoms (Marani and Giunchedi, 1976). 498-502. Kim, K.S. and Fulton, J.P. (1973). Association of virus-like References particles with a ringspot disease of oak. Pl. Dis. Reptr 57, 1029- Brierley, P. (1944). Viruses described primarily on ornamental or 1031. miscellaneous hosts. Pl. Dis. Reptr 150 Suppl. 410-482. Kristensen, H.R. (1963). Oak mosaic. Tidsskr. PlAvl. 67, 616. (mimeographed). Nienhaus, F. and Yarwood, C.E. (1972). Transmission of virus Marani, F. and Giunchedi, L. (1976). Alfalfa mosaic virus isolated from Oak leaves fractionated with Sephadex. Phytopathology from Rhamnus frangula in Italy. Acta. Hortic. 59, 97-101. 62, 313-315. Quiaoit, A.R. and Fulton, R.W. (1966). A disease of Rhamnus Schmelzer, K., Schmidt. H.E. und Schmidt, H.B. (1966). Virus cathartica caused by cucumber mosaic virus. Pl. Dis. Reptr 50, Krankheiten und virus ver dachtige Erscheinungen an Forstge- 613-614. holzen. Arch. Forstw. 15, 107-120. Schmelzer, K. (1974). Untersuchungen an Viren der Zier- und Yarwood. C.E. (1971). Erysiphaceae transmit virus to Cheno- Wildegeholze 8. Mitteilung : Neue Befunde an Forsythia, Hydran- podium. PI. Dis. Reptr 55, 342-344. gea und Philadelphus sowie Viren und Virosen an Rhamnus, Yarwood, C.E. and Hecht-Poinar, E. (1970). A virus resembling Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllum, Celastrus, tobacco mosaic virus in oak. Phytopathology 60, 1320. Staphylea und Cram be. Zbl. Bakt. ParasitKde 129 Abt. 11,139-168

R HODOD EN DRON-Ericaceae R HAM NUS-Rhamnaceae Foliage disease A graft transmissible variegation of Rhamnus sp. has been recorded but little studied (Brierley, 1944 cited SYMPTOMS : Concentric necrotic ring patterns in one reference). two-year-old leaves. Distribution : In horticultural cultivars of R hododen- Foliage diseases dron sp. in Oregon USA and British Colombia, Canada. SYMPTOMS : Yellowish green mosaic or chlorotic Transmission : By grafting from Rhodendron to bands, diminished leaf area and deformation. Kalrnia latifolia L on one occasion. Not in foliar Distribution : In USA (Quiaoit and Fulton, 1966) sap mechanically inoculated to a range of "herb- and East Germany (Schmelzer, 1974) affecting aceous hosts" (Coyier et al., 1977). Rhamnus cathartica L. Causal agent/Relationship : Unknown. Electron Transmission : In sap with Myzus persicae from microscopy revealed flexuous rod-shaped virus- and to "herbaceous hosts". like particles 460-540nm long and about 13nm in Causal agent/Relationship : Cucumber mosaic diameter in leaves with symptoms. virus was identified as a cause of the associated symptoms (Quiaoit and Fulton, 1966). COMMENTS : A similar syndrome in Kalmia latifolia was noted by Pearse (1968) who suggested that a SYMPTOMS : Light green yellowish, reddish or white virus might be the cause but did not report trans- lines on both sides of main veins or with similarly mission tests. coloured oak leaf patterns. References Distribution : In East Germany (Schmelzer, 1974). Coyier, DL., Stace-Smith, R., Allen, T.C. and Leung, E. (1977). Transmission : By budding to R. frangula but not Virus like particles associated with a rhodendron necrotic ringspot in sap inoculated to "herbaceous hosts". disease. Phytopathology 67, 1090-1095. Pearse, A.G.E. (1968). Diseases of ornamental plants. Gard. Causal agent/Relationship : Not known. Chron. 164, 5.

50 ROBIN IA—Leguminosae

Foliage diseases Stem disease

SYMPTOMS: Mosaaa MPTOMS - CHI c ear sy,ned ts foliage assoc•ated asM, .5 TS 6 fa, s.SST n. sHnu ef'ec: slim.. ate res gry ”to Sing:o ar na wood prodycson throsgO eFecTs on ecrt aors csar-- cuts and :ea.es oroarerate yrou:;a.t acout ysnen al: eter growth ; three-year-oSd nuasers s:ock hees Hected axlar: (clus ,n rarer :nstances ad.en7 bsbbis with robania mosaic vmars were sa d to be ha.f the he,ght deve cry a:to short succu ant hraoches beaong leases of controSs and Oess frast Masc./ (Schmelzer and with greati.; cra..n.sr ed area Ye,n a.earing may occur 1963: M.Ynko and ScOmezer. 1968). and leaf shape may be a•tered from bluntly rounded to Distribution : In the plaMs (but not mounta.nous pointed (Cullen, cited in Grant et al., 1942) Petiole regions) of Eastern Europe (Schmeizer, 1968) Æangth may be one f.fth of heaithy, root proliferation affecting up to 10% of Robin's pseudoacacia L.. may occur and the disease has been said to predispose R. pseudoacacia forma umbriculifera Hon and R. affected plants to w:nter injury or death (Grant, 1939; vIscosa Ventenat. Grant et al., 1942). Transmission: Experimentany in sap and via dod- astribution: Waters (1898) first described the der to -herbaceous hoatsa. NaturaHy by Aphis disease from R pseudoacacra in Maryland, USA cracwora Koch and experimentaY; by other aphids rncluding Myzus persicae Sulz. (Schmelzer and 1965, cited in Schmelzer, 1971; Milinko and Schmelzer, 1961; Milinko and Schmelzer, 1968). Propagation by top grafting to infected R. pseudoacacia stocks was said to be an important natural means whereby the virus was disseminated (Schmelzer and Milinko, 1963: Schmelzer, 1968). Causal agent/Reiationship Bobinia true mosaic virus (Echtes Pobinienmosaik Schmelzer, 1971) has been shown to cause mosaic symptoms but it is not the only virus which has been associated with this syndrome. Although bean yeaow mosaic (Bos, 1970) mfects R. pseudoacacia under experimental conditions to cause chlorohc mottle symptoms in leaves (Kovachevsky, 1968) and tobacco mosaic virus has been associated with a somewhat similar syndrome in Bulgarian Robnia (Atanasoff, 1965), Schmelzehs extensive work only revealed the follow!ng :—boet hngspot and potato bouquet serotynes of tomato hiackring and strawberry latent hngspot viruses. Pobima true mosaic virus has some properties in common with cucumber mosa:c virus and some with the unidentified virus associated with mosaic symptoms in R. pseudoacacia in the Chun-Chon area of South Korea (Kim, 1964: 1965) although the three viruses do not seem to have been compared in the same laboratory.

SYMPTOMS: Chlorotic blotches, spots and mosaic. ,47.-Ec 51Witches broom In Robin/a pseudoacacla associatea Distribution : In USA affecting R. pseudoacacia. with mycoplasma like organisms. Transm.ssinn. - • By grafting but not following

51 Dos, L. (1910) Bean yellow mosaic virus. I.IA A Descr, Plant V iruSeti no. 40.4 no :item R. and Code A. (1960) yus witches' !zooms of Ai oseudeacacia, a new disease for Italy) Am. 1st. bet iiniv Pavia Set 5, 17, 122-128. Fulton, J .P. and Kire K S (1E73) A virus resemaiind tomato spotted iciidt virus in black locust. PI, Drs. Reny 57, 153-155. Grant T.i . (1938a) Additional nntes on Me distribution of witches broom of black locust. PI Di.v. Reptr 22, 255-256. Grant. TJ (19385). Additional nates on the distribution of witcties' broom of black locust PI. as. Roprr 22, 53 Grant, T J. (19391. Further notes od the distribution af .idtches' broom of black locust PI as Reprr 23 41-43. Grant T Stout D C and Readev, J C. (1942). Systemic tircoming a yirus disease of black locust J For. 40 253-290 Grant 7 _I and Hartley. C. (1938) A witchesbroum on black locust and a similar disease on honey locust. PI DR. Rontr. 22, 28-31 Hartley . C. and Haas's F `A7 (1929). Brice:mina disease of black locust (Rotaraa osaiidecacia) ',,[90a theiag v 19 153-195 T.S. (1970f Tomato spt tted 0.ilt virus C M B Descr. Plant Viruses 'a, 39. 4 Dp Jackson L . A. and Haitl€3 C. (1933, Tieesmissibility of vie brcomene dise3se cit biaek t Foust PharapaRin/or1/2, 23 83 ae) Kim C (1954) Mosaic disease of black locust (R,abinia Fa-iv:Ina-51/2a L.) I. Sisimptsims and diansmissici) by grafting V. Pi Prot Korea 3, 1-5 Kim C.J. (19E5) Mosaic disease of Mack locust (Robinia pseudoacaccia L ). II Host rariae Forean rabic)/ 3, 22-2E. Kovachevsks C. rl 9E81Das Emenecitelbmosaik-virus in

Miliek», I. and SchneZzer K. (1961). Zur KeEntrus de( Mosaik- kiiankheit der Robinie iRcabinia 05(3)2/13yeacia L ). Peered:at/L. Z 41, 35-41. Milinka I. and Sonmedier. E. (1958). Some ne,e statements en He it 1 it• distribution and harmfu8tess of black locust mosaic in Hungary.

Echmelzer. K . (1968). Neue Befunde uner die geograpnische- Verbredung des Robinienmosaiks und uber seine ursachhoieic hut its occurrence in G8cagya and V4ginia before Viren. Aran. Forstw. 17, 521-523. 191)0 was indicated when herbanum specimens Schmelzer, K. (1971). Robinia mcisaic Virus. CALL/A 4.R. were examined (Hari ey and Haasis. 1929). The Descr. PRint Viruses, no. 55, disease aias beer reported in a iehucoi bosnded by Sehmelzer, K. and Mdkmc I. (1953). Bertrade zur Kenntais d3' Mosaikkrankheit dcr Robinie (Rehinia aseade-acacta L.) . Arc:1'. the A; anti,. •••IP east Pernshisdha l. .rth ar Forstw. 12, 1139-51. Seliskar, C.E.32/dsan, C.E. and Bourne C E (1973). Mitchialasmia Soath CarcHna (Grant. 1938a Er b Giant, 1939, -hke bodies found in phloem of black locust affected with Gran.: ard Hartleiy, 1938). A witches broom syn- witches' broym. RFRena(hcIogy 63 30-34. droree has also been reported frays Southern and Waters, C.E. ())398). sfatches' broom co tne locust. Pl. Pia 1, 83-84. Central Fbrooe (5hattny, 1959( &fern and Corte. 1960). Transmission Nalsist f(e(auent afung (Jack- son and Hartley, 1933), by haddinhd but not in sap ROSA-Rosaceae or with six named aphid species and -several unidentified leaf Happens and aohidsh (Grant er See plate 53, (Colour) 1942).

Causal agent/Pelatio shop: Se ishuar er el., (1973) tn cushn ifiitb other c an: material Au- icn has been detected an e ectrion croscope, M L 0 cs vegetate:era propagated fo( many years, noses frequently affected Usese. coontaTt Hsu:domes of vir3ses. There is an extensive literature reiating to draft- It is interesting to note thof ',botches' broom COMMENT: transmissible agents of Rosa scp , 39(ands and calt.vars, in Robima has not been reported ftom the totai geo- but uns' recentay very few eguses infect nu these plants graphus rdnge of R. psewicacac(s in 'We USA and that were characterized and their indendua - effects studied the known distianution cuincioes quite closely \PHI(' that in roses. White (1932) rev:E.:bed many of the earliest of elm phloem necrosis observat ons en infect.cas chlorosis ci4 roses in the USA and eisewhere and contrasted these symptoms with effects attributed to nutritional imbalance eatinsect Atanasytt, D. (1705). yiel f Erie, di Bitit9 16 523-525 feeding. Since then, a great number ef observatichs Rlattee C. (1957) Save been !ie9orged and `yam these I have chade a 5,)e_ what amitrars seiesscin cif h und4h8(s. Foliage diseases

tEr.er ea seeul!ng sto_ _ 5 .36 os itrairt,Utt

Cabsa agent Relatsfaris c5ffesent teoitio3ues !oersaa—s V.ansm'SSIE:r!5a,e •sMatect s Jae', hirial

Rosd, ti1,9/L15 Ltni 17'rd ol/3 ",;P: rrrr data fo–) st!).),H, ; Ha H5e. any, %I c3a5 (1962) (1925) FH,to6 11967, 1968) that a cH) sLestmrn •(523273 (51fere5t 533.55rtisns of Ha t a! t

nas fez!,

rasais!Hc5fte(ant (s5)23f!Krn Hal caused by 1967. 1972).

COMMENTS. 15 UK, (fors r.-HSJ .amses have been detectel in in N:U!e aw,-.)1e(rHse mosalc and prunus necrtstic tangiscyt '.,fiJses t Farrar and Frust, coed in H6 and Pros)), 1974). Ho)(ve...er, Funn

(1970) tetsasinized a ctist.nct sy333rame 2) R. selagera Piate 54-5 (pet of the 55!nyar Baccaratsbvwrnq and st!!(.5ed 'Hat He55.2ar cr!lorutha Itat(.1)(H), vein chlGrostswhen haturally irilected with strawberry latent nnttspet virua

53 (PVP), 2-Mercaptoethanol and phosphate buffer Transmission : By budding to R. multiflora but not pH 80. Fulton (1976) transmitted a virus to in sap to "herbaceous hosts" (Schmelzer, 1967). "herbaceous hosts" from affected roses. Fulton also transmitted the agent from roses by grafting Causal a ent Relationshi s : Not known. with seedling Prunus mahaleb L.. P. persicae Batsch. and P. pennsylvanica L. and hence from Prunus spp. to rose again. OTHER : In Czechoslovakia, the cowl forming condi- Causal agent/Relationship : A variant of prunus tion affecting leaves of R. cervensia Hudson, R. moyesii necrotic ringspot virus having few, if any, serologic- Hemsl. and Wilson and R. rugosa Thunb. noted by al determinants not held in common but differing Klastersky (1951) was reportedly transmissible by in its requirements for PVP for mechanical trans- grafting. mission from rose. Other prunus necrotic ring- In the UK, Hollings (1961) recorded (without details) spot and apple mosaic virus isolates were isolated the occurrence of three graft-transmissible disorders from roses showing yellow net symptoms on lower affecting either the leaves or flowers of rose cultivars and mosaic on upper leaves (Fulton, 1976). and Farrar and Frost (1972) recognized a distinctgraft- transmissible flower break symptom which was associa- COMMENTS : Most vein yellowing is undoubtedly ted with spherical virus-like particles visible with the associated with and probably caused by ilarviruses. aid of an electron microscope (Farrar and Frost cited in However, in the Netherlands (van Hoof and Caron, I kin and Frost, 1974). 1975) and in UK (Cammack, 1966 ; Harrison, 1967 ; Somewhat more detailed research has been devoted to lkin and Frost, 1974), some foliar flecking and vein an investigation of the bud proliferation, wilt and die- yellowing has been associated with strawberry latent back syndrome which was probably first noted in ringspot virus. This virus has also been associated with Australia (Grieve, 1931) although similar conditions mosaic, mottling, strapping, puckering or twisting of have been reported from Italy, Czechoslovakia, New leaves, diminished leaf size and a somewhat bushy Zealand (Fry and Hammett,1971 and others cited there- habit (causing economic damage in standard roses ; in), the USA (Cheo, 1970), the UK (Hutton, 1970 ; lkin I kin, 1971). Data are few but it seems noteworthy that and Frost, 1974 ; Hollings et al., 1973; Sweet, 1974) diminished vigour and possibly some of the effects on and the Netherlands (Bos and Perquin, 1975). Al- leaves which have been attributed to this virus may, in though parts of the syndrome seem to have been trans- glasshouse conditions, be partly caused by the feeding mitted by grafting (Fry and Hammett, 1971 ; Sweet, effects of high populations of Xiphinema, Longidorus 1974 ; Slack et al., 1976b) others have failed to achieve and Pratylenchus nematodes (Brown, 1965; Winfield, transmission of the agent(s) in this or in any other way 1974). Vein yellow net symptoms affeCting R. multi- (lkin and Frost, 1974). Bos and Perquin (1975) re- flora in the USA with additional dwarfing and epinasty viewed most of the relevant literature and considered (rose spring dwarf) were due to graft-transmitted agents many of the alternate possibilities but without implica- not studied in detail (Traylor et al., 1971 ; Slack et ting any specific aetiological agent. It seems likely that al., 1976a Er b). the syndrome will be found to be due to a complex of interacting factors ; physiological and environmental influences, perhaps virus, mycoplasma (MLO were Stem diseases reportedly observed in diseased but not healthy roses ; Atkey and Thomas 1976) and/or incipient Verticillium SYMPTOMS : Shortening of internodes, precocious wilt. axillary bud break and anthocyanescence of leaves. Roses with green petals are highly prized in horticul- ture; this effect is in some instances a symptom of Distribution : In the Northern states of the USA disease. In the U.S.S.R. studies confirmed that the affecting R. eglanteria L., R. woodsii Lindl., R. condition was transmissible muldflora Thunb. and R. rubrifolia Vill. by grafting and with dodder (Cuscuta campestris). MLO were associated Transmission : By grafting and apparently by with the symptom (Protsenko et al., 1972 ; Protsenko eriophyid mites (Phyllocoptes fructiphilus Koch) and Surgucheva, 1975). but not Tetranychus urticae Koch (Allington, et al., 1968). References Causal agent/Relationship : Not known. Allington, W.B., Staples, R. and Viehmeyer, G. (1968). Trans- mission of rose rosette virus by the eriophyid mite Phyllocoptes fructiphilus. J. econ. Ent. 61, 1137-1140. SYM PTOMS : "Rose streak" discolouration (browning) Atkey, P.T. and Thomas, B.J. (1976). Ultra thin sections of rose. of the bark. Less frequently the rachis, main veins or Rep. Glasshouse Crops Res. Inst. 1975, 128. Basit, A.A. and Francki, R.I.B. (1970). Some properties of rose stipules of leaves may be similarly discoloured and mosaic virus from South Australia. Aust. J. biol. Sci. 23, 1197— fruits may show brown spots, arcs or concentric ring 1206. patterns. Bos, L. (1976). Symptom expression and variation of rose mosaic. Neth. J. Pl. Path. 82, 239-249. Distribution : In the USA (Brierley, 1935), in East Bos, L. and Perquin, F.W. (1975). Rose bud proliferation, a disorder of still unknown etiology. Neth. J. Pl. Path. 81, 187-198. Germany (Schmelzer, 1967) and probably in the Brierley, P. (1935). Streak, a virus disease of roses. Phytopathology UK (lkin and Frost, 1974). 25, 7-8.

54 Brier ley, P. and Smith, F.F. (1940). Mosaic and streak diseases of Rose leaf curl, a distinct component of a disease complex which rose. J. agric. Res. 61 625-660. resembles rose wilt. Pl. Dis. Reptr. 60, 178-182. Brown, E.B. (1965). Xiphinema diversicaudatum and Longido- Sweet, J.B. (1974). Virus infections of woody rosaceous orna- rus macrosorna in rose glasshouses. Pl. Path. 14, 45-46. mentals. M.Sc. Thesis. University of Bath. Cammack, R.H. (1966). Soil-borne viruses in rose Pl. Path. 15, Thomas. H.E. and Massey, L.M. (1939). Mosaic disease of the 47-48. rose in California. Hilgardia 12, 647-663. Casper. R. (1973). Serological properties of prunus necrotic Traylor, J.A., Wagnon, H.K. and Williams, H.E. (1971). Rose ringspot and apple mosaic virus isolates from rose. Phytopath- spring dwarf, a graft-transmissible disease. Pl. Dis. Reptr 55, 294. ology 63, 238-240. White, R.P. (1932). Chloroses of the rose. Phytopathology 22, Cheo, P. (1970). Rose wilt or dieback-a new virus disease 53-69. attacks roses in California. Lasca Leaves 20. 88-89. Willison, R.S.. Weintraub, M.. and Ferguson, J.D. (1956). Purifi- Farrar, E.H. and Frost, R.R. (1972). A new disease of roses in cation and electron microscopy of viruses causing cherry yellows Britain. Pl. Path. 21, 97. and related diseases. Can. J. Bot. 34, 86-103. Fry, P.R. and Hammett, K.R.W. (1971). Rose wilt virus in New Winfield, A.L. (1974). Observations on the occurrence, patho- Zealand. N.Z. J. Agric. Res. 14, 735-743. genicity and control of Pratylenchus vulnus. P. thornei and Fry, P.R. and Hunter, J.A. (1956). Rose mosaic virus in New Xiphinema diversicaudatum associated with glasshouse roses. Zealand. N.Z. J. Sci. Technol. 37, 478-482. Ann. appl. Biol. 77, 297-307. Fulton, R.W. (1952). Mechanical transmission and properties of rose mosaic virus. Phytopathology 42, 413-416. Fulton, R.W. (1967). Purification and serology of rose mosaic virus. Phytopathology 57, 1197-1201. Fulton. R.W. (1968). Serology of viruses causing cherry necrotic ROMNEYA-Papaveraceae ringspot, plum line pattern, rose mosaic and apple mosaic. Phytopathology 58, 635-638. Fulton, R.W. (1970). A disease of roses caused by tobacco streak Hollings (1961) detected cucumber mosaic virus in virus. PI. Dis. Reptr 54, 949-951. Romneya coulteri Harvey showing faint mottling of Fulton, R.W. (1972). Apple mosaic virus. C.M.I.IA.A.B. Descr. leaves but did not report tests to infect healthy Romneya Plant Viruses no. 83,4 pp. with the virus. Fulton, R.W. (1976). An isolate of prunus necrotic ringspot virus from rose with yellow net symptoms. Mitt. biol. BundAnst. Ld-u. Reference Forstw. 170, 29-32. Hollings, M. (1961). Virus and its effect on some ornamental Grieve, B.J. (1931). Rose wilt or dieback, a virus disease of roses shrubs. Nurserym. Seedsm. Glasshouse Grower 132, 930-931. occurring in Australia. Aust. J. exp. Biol. med. Sci. 8. 107-121. Halliwell, R.S. and Milbrath, J.A. (1962). Isolation and identification of tomato ringspot virus associated with rose plants and rose mosaic virus. PI. Dis. Reptr. 46. 555-557. Harrison, B.D. (1967). The transmission of strawberry latent ringspot virus by Xiphinema diversicaudatum (Nematoda). Ann. SALIX-Sa/icaceae appl. Biol. 60, 405-409. Hollings, M. (1961). Virus and its effect on some ornamental Stem Disease shrubs. Nurserym. Seedsm. Glasshouse Grower 132. 930-931. Hollings, M., Stone, 0.M., Brunt, A.A., Atkey, P.T. and Fry, P.F. SYMPTOMS : Brooming, narrowing and chlorosis of (1973). Rose. Rosa spp. In Virology. Rep. Glasshouse Crops Res. Inst. 105. leaves and predisposition to winter injury. Hoof. H.A. van and Caron, J.E.A. (1975). Strawberry latent ring - Distribution : In Czechoslovakia affecting Salix spot virus-infected fields of Rosa rugosa produce healthy cuttings triandra L., S. viminalis L., S. babylonica (=S. but diseased rootstocks for standard roses. Meded. Fac. Land- bouw. RijksUniv. Gent 40, 759-763. salmoni Carriere Hort), S. aurita L., S. caprea L.. S. Hutton, B. (1970). Stunt disease-and work at Shardlow. alba L., S. pentandra L. (Svobodova et al., 1962 Gdnrs' Chron. 168, 31-33. cited in Schmelzer, 1968). In USA affecting S. lkin, R. (1971). Virus diseases of roses. Ph.D. Thesis, University rigida Muhlenberg (Holmes et al., 1972). of Manchester. lkin, R. and Frost, R.R. (1974). Virus diseases of roses. I. Their Transmission : By grafting. occurrence in the United Kingdom. Phytopath. Z. 79, 160-168. Causal agent/Relationship : Phloem of diseased Klastersky, I. (1951). (A cowl forming virosis in roses, lime trees (but not symptomless) trees in the USA contained and elm trees). Studia bot. csl. 12, 73-121. McDaniel, G.L., Buck, G.J. and Ford, R.E. (1971). Isolation of micro-organisms bounded by walls rather than tobacco ringspot virus from rose. Phytopathology 61, 45-49. membranes thereby indicating their resemblance to Protsenko, A.E., Kuvshinova, E.V. and Protsenko, E.P. (1972). rickettsia rather than mycoplasma-like organisms Deformation and green petal in roses caused by virus infection. (Holmes et al., 1972 ; Maramorosch, 1974). (Hort. Abstr. 1973,43, 2295.) Protsenko, A.E. and Surgucheua, N.A. (1975). On the nature of rose flowers turning green. (Hort. Abstr. 1976,46, 3629.) COMMENT : Salix caprea L. became symptomlessly Sastry, K.S.M. (1966). Yellow vein mosaic of Rosa bourbiana. but systemically infected with poplar mosaic virus Indian Phytopath. 19, 316-317. when grafted with Pxeuramericana '0P226" scions as Schmelzer, K. (1967). Die Strichelkrankheit der Rose (Rose streak) in Europa. Phytopath. Z. 58, 92-95. donors (Cooper, unpublished data). Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2,232- References 303. Berlin : Akademie-Verlag. Holmes, F.O., Hirumi, H. and Maramorosch, K. (1972). Witches' Secor, G.A. and Nyland, G. (1978). Rose ring pattern : a compon- broom of willow: Salix yellows. Phytopathology 62, 826-828. ent of the rose-mosaic complex. Phytopathology 68, 1005-1010. Maramorosch, K. (1974). Mycoplasrnas and rickettsiae in relation Slack, S.A., Traylor, J.A., Nyland, G. and Williams, H.E. (1976a). to plant diseases. Ann. Rev. Microbiol. 28, 301-324. Symptoms, indexing and transmission of rose spring dwarf Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : disease. Pl. Dis. Reptr 60, 183-187. Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2,232- Slack, S.A., Traylor, J.A., Williams, H.E. and Nyland, G. (1976b). 303. Berlin : Akademie-Verlag.

55 SAM BUCUS—Caprifoliaceae

Foliage diseases

aras er, er S race •1974.; He ecran: ,,,cr ern:a 1 195D) s r r

N3r-na

S 1PTOVS Cblaretio D:stribc'cor r-er;ca affecvng Samorl•us 0971 ar.cd C[[,[t[a dens; s L. herr: frarn [H[714 [ arced rarcs—.iss.or : H sap to -herbaceous rcstsc. _brines and ',:crrer ; 1971) s! Causa! aaent;Relat,orship Geiden e derberra •!ras (—cmerry leaf roll v,rus) Other viruses

Corn mon oo'uole'i gebIen eorerberrc iso.ated frcm S. canaciensm but v,,Hth unproven ,scarere raf Herr/ !ear rul 'us fmiomoS . si causal assaciatee with disbnc; simptoms are

Plate 57—Leaves of Sambucus canadenes showinq chlorritic oa leaf symptoms which formed following Inc) ulation with elderberry latent virus.

56 tobacco mosaic (Mueller, 1967), tomato ringspot Lister, R.M. (1964). Strawberry latent virus: a new nematode- (Uyemoto, 1970), cucumber mosaic and tobacco borne virus Ann. appl. Biol. 54. 167. Mamula, D. and Milicic, D. (1975). Cherry leaf roll virus in necrosis plus its satellite virus (Uyemoto and Sambucus ebulus L. Acta Horticulturae 44, 33-37. Gilmer, 1971). A virus which Jones (1972) called Mueller, W.C. (1967). Tobacco mosaic virus obtained from dis- 'elderberry virus A' was detected in S. canadensis eased Wisteria and elder. Pl. Dis. Reptr 51. 1053. imported into Scotland from the USA Its pro- Schmelzer, K. (1966). Untersuchungen an Viren der Zier und perties were not studied in detail but it had flexuous Wildgeholze. 5. Mitteilung : Virosen an Popuhrs und Sambucus. Phytopath. Z. 55, 317-351. rod-shaped particles and may be similar to the Stefanac, Z. (1969). Nalaz virusa uvijenosri lista tresnje (cherry carlavirus isolates from Sambucus sp. (presumably leaf roll virus) u Jugoslaviji. Acta bot. croat. 28, 373. S. nigra) from England and Scotland. A virus with a Uyemoto, J.K. (1970). Symptomatically distinct strains of tomato similar morphology to elderberry virus A was ob- ringspot virus isolated from grape and elderberry. Phytopathology tained from S. canadensis in USA (Uyemoto and 60, 1838-41. Uyemoto, J.K. and Gilmer, R.M. (1971). Sap transmissible viruses Gilmer, 1971). Jones (1972) isolated a different from elderberries in New York. Phytopathology 61, 132. virus which he called 'elderberry latent' from S. Wetter. C. (1971). Carnation latent virus. C.M.I.IA.A.B. Descr. canadensis cv Adams No. 2. This virus, which was Plant Viruses. no. 61. not transmitted non-persistently by representatives Yarwood, C.E. (1959). Virus increase in seedling roots. Phyto- of two aphid genera, had spherical particles of two pathology 49, 220-223. main sizes and caused transient chlorotic ringspot and line patterns to form in some but not all leaves of S. canadensis cv Adams No. 2 systemically infec- S KI M M IA-Rutaceae ted following experimental mechanical inoculation. In a brief report, Varney (1965) stated that tobacco ringspot virus was detected in an unidentified plant of OTHER : Chlorotic blotching, in some instances associ- Skimmia with ringspot symptoms in its leaves. The ated with necrotic flecks or rings in S. racemosa L. has isolate infected two Skimmia clones systemically but also been associated in the DDR and in Yugoslavia did not cause symptoms. with isolates of cherry leaf roll virus (Schmelzer, 1966 ; Stefanac, 1969). In Southern Finland, S. racemosa References infected with cherry leaf roll virus and an unidentified Varney, E.H. (1965). A ringspot virus disease of Skimmia sp. carlavirus, showed chlorotic blotching in spring foliage. Phytopathology, 55, 131. However, in summer/autumn, leaves on infected plants had bright yellow ring patterns (Cooper, unpublished data). SO LA N UM-Solanaceae Cherry leaf roll virus was also transmitted from S. ebulus L. in Yugoslavia. The infected Sambucus showed Foliage disease chlorotic foliage symptoms not proved to be due to the associated virus (Mamula and Milicic, 1975). SYMPTOMS : Diffuse mottling, malformation and on some leaves severe mosaic. References Distribution : In Solanurn crispurn Ruiz and Pay. Blattny, C. and Oswald,-V. (1950). Virosy bezu cerneho (Sam- in U.K. bucus nigra). Ochr. Rost. 23, 9-11. Brunt, A.A. and Stace-Smith, R. (1971). Viruses occurring in wild Transmission : Mechanically in leaf sap to "herb- plants. Rep. Glasshouse Crops Res. Inst. 1971,121. aceous hosts". Cadman, C.H. (1960). Studies on the relationship between soil- borne viruses of the ringspot type occurring in Britain and Con- Causal agent/Relationship : Cucumber mosaic tinental Europe. Virology 11, 653-64. virus was identified but not proved to cause the Hansen, A.J. (1967). A virus from golden elderberry. Phyto- disease (Cooper unpublished data). pathology 57, 813. Hansen, A.J. and Stace Smith, R. (1971). Properties of a virus COMMENT : Only one woody climber included. There isolated from Golden elderberry, Sambucus nigra aurea. Phyto- pathology 61, 1222-9. are numerous additional viruses recorded from herb- Harrison, B.D. and Winslow, R.D. (1961). Laboratory and field aceous species such as the potato. studies on the relation of arabis mosaic virus to its nematode vector Xiphinema diversicaudatum (Micoletzky). Ann. appl. Biol. 49, 621-629. Helebrant, L. (1969). Contributions to the virus research of SO R B US-Rosaceae lacinate woody plants. In : Proc. Conf. Czech. Plant Virologists, 6th, 1967,192-196. Academia Prague. See plate 58a (Colour) Horvath, J., Schmelzer, K. and Juretic, N. (1974). Isolierung deskirschenblatt roll virus (cherry leaf roll virus) aus Sambucus In East Germany, graft transmissible chlorosis and nigra L. in Ungarn. Acta Phytopathol. Acad. Sci. Hung. 9, 209- 218. variegation of Sorbus aucuparia L. was noted by Baur Jones, A.T. (1972). Purification and properties of elderberry (1907). Although the cause remains to be determined latent virus, one of four sap-transmissible viruses obtained from it may be significant that somewhat similar symptoms American elder (Sambucus canadensis L.). Ann. appl. Biol. 70, formed in leaves of S. aucuparia inoculated with apple 49-58. mosaic virus (Kegler cited in Schmelzer, 1968). Kegler Jones, A.T. and Murant, A.F. (1971). Serological relationship between cherry leaf roll, elm mosaic and golden elderberry (1959/60) reported the graft transmissibility of a viruses. Ann. appl. Biol. 69, 11-14. distinct agent causing yellow-whitish flecks, rings

57 and lines in leaves of affected plants. This condition serotype of tomato blackring, was associated with is frequent in S. aucuparia.. in UK and in Finland diffuse-transparent yellowing in foliage of S. trifolia L. but has not to date yielded viruses transmissible in foliar (Schmelzer, 1974). Neither virus was reported to have .sap to herbaceous hosts (Cooper, unpublished data). been reintroduced into healthy Staphylea plants. Although no virus was detected following inoculation of Sorbus leaf sap to herbaceous test plants, Sweet Reference (pers. comm.) using a double budding technique and Schmelzer, K. (1974). Untersuchungen an Viren der Zier- und woody indicators, induced stunting and leaf chlorosis Wildegeholze 8. Mitteilung Neue Befunde an Forsythia. Hydran- gea und Philadelphus sowie Viren und Virosen an Rhamnus, (symptoms typical of apple chlorotic leaf spot virus) in Centaurea, Galvezia, Cistus, Forestiera, Abeliophyllum, Celastrus, Malus platycarpa and the Russian clone R 12740-7A of Staphylea u n d Crambe.Zbl. Bakt. ParasitKde 129 Abt. //, 139-168. M. sylvestris (both on rootstocks of M. sylvestris cv Tremlett's Bitter) following inoculation with buds either from a symptomless Sorbus thianshanica Rupricht or SYMPHORICARPUS—Caprifo/iaceae from S. aucuparia with yellowing and line patterns in the foliage. His observations confirmed and extended In a brief report, van Hoof and Caron (1975) reported that of Kralikova (1961). An apple isolate of chlorotic the isolation of strawberry latent ringspot virus from leaf spot virus induced a stunt in some but not all leaves of S. albus Blake : symptoms were not described. Sorbus aucuparia seedlings which were experimentally infected following bud grafting (Sweet and Campbell, Reference 1976) van Hoof, H.A. and Caron, J.E.A. (1975). Strawberry latent ringspot virus-infected fields of Rosa rugosa produce healthy cuttings References but diseased rootstocks for standard roses. Meded. Fac. Land- Baur, F. (1907). Uber infektiose chlorosen bei Ligustrum, Lab- bouw. RijksUniv. Gent 40, 759-763. urnum, Fraxinus, Sorbus und Ptelea. Ber. dt. bot. Ges. 25, 410— 413. Kegler, H. (1959/60). Das Ringfleckenmosaik der Eber esche SYRINGA—Oleaceae (Sorbus aucuparia L.). Phytopath. Z. 37, 2,14-216. Kralikova, K. (1961). Kruzkov it ost jarabiny v CSSR. Biologia, Bratisl. 16, 835-838. Foliage diseases Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : PFlanzliche Virologie (edited by M. Klinkowski, vol. 2 part 2, SYMPTOMS : Diverse array including light green ring 232-303. Berlin : Akademie-Verlag. and line patterns with occasional distortion, leaf crack- Sweet, J.B. and Campbell, A.I. (1976). Pome fruit virus infec- ing, and "shot hole" effects. Symptoms sometimes /ions of some woody ornamental and indigenous species of Rosaceae. J. hort. Sci. 51, 91-9. transient or restricted to a few leaves. Ringspot (Atanasoff, 1935) ; ringspot mosaic (Smolak and Novak, 1950). SPIRAEA—Rosaceae Distribution : Bulgaria (Atanasoff, 1935), The Netherlands (van Katwijk, 1955), many other See plate 58b (Colour) European countries (Schmelzer and Schmidt, 1966 ; Novak, 1969) and the USA (Beale and Spiraea douglasii Hooker with leaves showing vein Beale, 1952). yellows and enations yielded arabis mosaic virus to Transmission : Parts of the syndrome (agents) by herbaceous test plants. However, it seems unlikely that grafting between 1) named S. vulgaris clones this virus caused these symptoms because AMV was (Protsenko and Protsenko, 1950 ; Beale and Beale, also detected in symptomless Spiraea x bumalda Burr. 1952) and 2) lilac with symptoms of ringspot. cv Antony Waterer and S. japonica alba Nichols (S. Also agents when the latter was grafted to other albillora (Mig.) Zab) (Sweet 1974). Schmelzer (1970) Oleaceous genera (Novak, 1969). also isolated AMV from an unnamed cultivar of S. x bumalda showing vein yellow net symptoms. Causal agent/Relationship : The main cause is unknown. A hitherto undescribed virus, lilac ring References mottle, was transmitted mechanically to "herb- Schmelzer, K. (1970). Untersuchungen an Viren der Zier- und aceous hosts" inoculated with sap from lilac foliage Wildgeholze. 7. Mitteilung : Weitere Befunde an Buddleja, but was not consistently associated with ringspot Viburnum, Caryopteris und Philadelphus sowie Viren an Leyces- symptoms (van der Meer, et al. 1976). Other teria, Chionanthus, Ribes, Hydrangea, Syringa, Spiraea und viruses occasionally associated with ringspot Catalpa. Phytopath. Z. 67, 285-326. Sweet, J.B. (1974). Virus infections of woody rosaceous orna- disease include elm mottle (Schmelzer, 1969), mentals. M.Sc. Thesis, University of Bath. strawbery latent ringspot (van der Meer, 1976) arabis mosaic (Cooper, 1975) and tobacco rattle (Huttinga, 1972). Bacteria (Pseudomonas syringae STAPHYLEA—Staphyleaceae Van Hall) have also been implicated (Novak and Lanzova, 1975 ; 1977). Following manual inoculation of "herbaceous hosts" inoculated with foliar sap from Staphylea emodi Wahl. SYMPTOMS : Chlorotic watermark or "oak-leaf" band- (showing green mottle symptoms) arabis mosaic virus ing patterns with interveinal chlorosis, "chlorotic was identified. This virus, with the beet ringspot ringspot" (Novak, 1969).

58 11969) de*.ec:ed rss 0 po of it. h•:e aoen: •Rea:onsbp. (1969) 'aarC 'ir 1973 roses /u,gar,s. 107,H, 1977i Aere 0se Cas,sa acer: Re at e ceds,se frsi- /-7.us e•- dic'd e cease. A e 5,r resemb es sda: s:ud ed 0. Bea e a-d •so.a.:e of ei'm caused white rsicsa Bea e i19.62„ ss.dd..es'.edmat sdsease n 3c : 12 5 vu/gar:s see:: .rgt: Ssi—e.zer -.E... be a tne age-. caus -dsoct (1 969) was subsegjer a 70 recoier p sease More iersent and Larizo..a (1975. from affectec o ants. 1977) rep:r:ed detectiy,: arab 5 mcsa 6. and enerry .eaf . Cri0rh COMMENT Siimptoms of . te mosa c resemb•e cisease tose of streak mosaic: (necrotic ringspot) reported A nitnerto undescribed ‘,..rus having fiexuous rod- from Czechosiovak,a (Smoak and Novak. 1950: snaped particies (10 x 1200nm) was assoc ated Novak 1969) but attempts to transmit streak mosaic with -chlorotic* :eafspot disease (Brint, 1978) have not been noted. The pathogenicity of the virus for Lac was not recorded In experimentanv :nfected Chenopodium SYMPTOMS . In a specimen, (25 years old) of Syringe quInoa and Phase

SYMPTOMS Pale yellow to white mosaic patterns in S. vulgans (white mosaic). Other symptoms include chlorotic, but not necrotic, rings or broad white chevron patterns and on occasions the affected white leaves become curled Distribution East Germany (Schmelzer and Schmidt. 1966) Transmission By grafting (Schmelzer and Schmidt 1966) In tests done early in spring Schmelzer (1969) transmitted a virus from S. vulgarts to herbaceous hosts' using leaf sap, transmission being aided when inocula were buffered with phosphate solutions The virus was not transmitted via dodder (Cuscuta califorroca Choisy or C. subinclusa Dur. et Hilg ). Attempts to find aphid Plate 59-Leaves of Syringe vulgalis cv Michael Buchner in- vectors have been unsuccessful, but Schmelzei ;:culated by budding and showing chlorotic ring and line patterns. Although arabis mosaic virus has been transmitted from bushes *Tire assimiatad symptiams in lilt: chrnme yelliasy rathor .-vith similar symptoms, other viruses have also been associated. Man chlsirotic line patterns.

59 which rolled at their margins, became brittle before order of lilacs : etiological role of urban-generated air pollutants. dropping to expose stem apices which were then liable J. Am. Soc. hort. Sci. 99, 508-514. Hibben, C.R. and Walker, J.T. (1966). A leaf roll necrosis com- to early autumnal frost injury. Similarly complex arrays plex of lilacs in an urban environment. Proc. Am. Soc. hort. Sci. of symptoms including leaf rolling associated with dark 89, 636-642. coloured or necrotic etching were reported by Schmel- Huttinga. H. (1972). Interaction between long and short particles zer, (1968). of tobacco rattle virus. Meded. Inst. plziektenk. Onderz. no. 610. Graft-blight (Chester, 1931 ; Cadman, 1940 ; Smith, Kochman, J., Kowalska, H. and Szymanska, B. (1964). Under- suchungen uber Virosen des Flieders (Syringa vulgaris L.) und 1940) occurs universally when Syringa spp. are grafted des Ligusters (Ligustrum vulgare L.). Phytopath. Z. 51, 333-350. to Ligustrum rootstocks as was common in horticul- Lorentz, P. and Brierley, P. (1953). Graft transmission of lilac tural practice. Even though rootstocks appear normal, witch's broom. Pl. Dis. Reptr 37. 555. foliar blight tends to increase in severity as the grafted Novak, J.B. (1966). (Transmission and dissemination of virus plants age, with mottling, inward rolling and foliar diseases on some woody plants.) Sb. vys: Sk. zemed. Praze 1966, 471-484. death occurring in the second and third years. Novak, J. (1969). Investigation of virus diseases of lilac. Proc. Distribution : Wherever Syringa spp are grown. Conf. Czech. Plant Virologists, 6th, Olomouc (1967), 289-293. Novak, J.B. Ei Lanzova, J. (1975). Etiology of two virus diseases Transmission : Although Smith (1940) reported of lilac (Syringa vulgaris L.) occurring in Czechoslovakia. the transmission of graft blight between different Biologia Pl. 17, 226-227. Syringa spp., Cadman (1940) questioned Chester's Novak, J.B. and Lanzova, J. (1977). Purification and properties (1931) earlier evidence because symptoms did not of arabis mosaic and tomato bushy stunt viruses isolated from lilac (Syringa vulgaris L.). Biologia PI. 19, 264-271. develop when Syringa scions grew away from their Protsenko, E.R. and Protsenko, A.E. (1950). Ring mosaic of lilac, own sucker roots. an infectious disease. Bull. bot. Gdn., Moscow, 5, 46-50 Causal agent/Relationship : Unknown but similar Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : symptoms of leaf roll and necrosis have been Pflanziche Virologie (edited by M. Klinkowski, vol 2, part 2,232- 303. Berlin : Akademie-Verlag. attributed in the USA to atmospheric pollutants Schmelzer, K. (1969). Das Ulmenscheckungs-Virus. Phytopath. (Hibben and Walker, 1966 ; Hibben and Taylor, Z. 64, 39-67. 1974). Bacteria might also be involved (see Schmelzer. K. (1970). Untersuchungen an Viren der Zier-und Novak and Lanzova, 1977). Wildgeholze. 7. Mitteilung : Weitere Befunde an Buddleja, Viburnum, Caryopteris und Philadelphus sowie Viren an Leyces- teria, Chionanthus, Ribes, Hydrangea, Syringa, Spiraea und Stem disease Catalpa. Phytopath. Z. 67, 285-326. Schmelzer, K. and Schmidt, H.E. (1966). Die Viruskrankheiten SYMPTOMS : In S. japonica Decne witches' broom des Flieders. Arch. Gartenb. 14, 303-314. tending to occur in the upper parts of affected plants as Smith, K.M. (1940). Graft-blight of lilacs. Gdnrs'. Chron. 1940, abnormally slender, freely 'branching lateral shoots cvii, 2778,144. Smolak. J. and Novak, J.B. (1950). Virove choroby seriku. Och. bearing leaves of about one quarter normal size. Leaves Rost. 23, 285-304. are additionally twisted, rolled or may show chlorotic Van Katwijk, W. (1955). Ringvlekken mozaik bij seringen in flecks (Brierley, 1951). In S. vulgaris, thin lateral shoots Nederland. Meded. Dir. Tuinb. 18, 823-828. develop at the expense of the main stems : the smaller Van der Meer, F. A. (1976). Observations on lilac ringspot. leaves having additional vein clearing symptoms Acta Horticulturae 59. 105-111. Van der Meer, F.A., Huttinga, H. and Maat, D.Z. (1976). Lilac (Lorentz and Brierley, 1953). ring mottle virus : isolation from lilac, some properties, and relation Distribution : USA. to lilac ringspot disease. Neth. J. Pl. Path. 82, 67-80. Waterworth, H.E. (1972). Purification, serology and properties of Transmission : By grafting but not byimechanical a virus from lilac. Syringa oblata affinis. Pl. Dis. Reptr 56, 923- transmission in foliar sap. 926. Wetter, C. (1971). Carnation latent virus. C.M.I.IA.A.B. Descr. Causal a ent/Relationshi s : Unknown, possibly Plant Viruses. no. 61. mycoplasma-like particles will be associated. References TAX U S- Taxaceae Atanasoff, D. (1935). Old and new virus diseases of trees and shrubs. Phytopath. Z. 8, 197-223. Beale. J.H. and Beale, H.P. (1952). Transmissions of a ringspot- Taxus baccata L. cv Aurea in Czechoslovakia has leaves virus disease of Syringa vulgaris by grafting. Contr. Boyce which are golden yellow when young but which Thompson Inst. Pl. Res. 17, 1-6. change colour to a pale green in Autumn. Blattny Brierley, P. (1951). A witches' broom of lilac. Pl. Dis. Reptr 35, (1960) reported transmitting the yellow leaf variegation 566. agent by grafting but with few details. Brunt, A.A. (1978). The occurrence, hosts and properties of lilac chlorotic leaf spot virus, a newly recognised virus from Syringa vulgaris. Ann. appl. Biol. 88, 383-391. Reference Brunt, A.A. Et Stace-Smith, R. (1978). The intracellular location Blattny, C. (1960). Weiterer Beitrag zur Kenntnis der Nadelbaum of lilac chlorotic leafspot virus. J. gen. Virol. 39, 63-71. virosen. Preslia 32, 414. Cadman, C.H. (1940). Graft-blight of Lilacs. Gdnrs' Chron. cvii, 2768,25. Chester, K.S. (1931). Graft-blight : a disease of lilac related to the TI LI A- Tiliaceae employment of certain understocks in propagation. J. Arnold Arbor. 12, 79-146. Two virus-like conditions are reported to affect species Cooper, J.I. (1975). Arabis mosaic virus, a cause of chlorotic symptoms in leaves of Fraxinus excelsior L. Pl. Path. 24, 114-116. of Tilia in Eastern Europe. Cowl-formation by leaves of Hibben, C.R. and Taylor, M.P. (1974). The leaf roll-necrosis dis- T. platyphyllos Scop., T. cordata Mill., T. macrophylla

60 Plate 2a Graft incompatibility (cause unknown) showing as a brown line at the union between Acer pseudoplatanus seedling rootstock and an A. rubrum scion.

Plate 2b Graft incompatibility showing as stem pitting at the union between the scion R 12740/7A "Russian apple" (a 'woody indicator') and Ma lus sylvestris rootstock. At least two virus-like agents were present Spy epinasty and apple stem pitting. Plate 11 b Double diffusion serology in agarose jelly. The central well conHius antiserum to a birch isolate of cherry leaf roll virus. Surrounding this are wells containing sap from herbaceous hosts infected with birch (b) or elder (e) isolates. Wells at righf (h) contain sap from healthy plants. The white precipitin lines show spur formation (arrowed),

Plate 14 Sunflower petals showing on the left that petals have been converted to leaf like structures—a yllopy 1rls svmptom is typically associated with mycoplasrna-like organisms. Plate 16 Distant view of a specimen Aesculus hippocastaneum showing the general yellow appearance: a symptom associated with an ilarvirus.

.1A Plate 77 Close-up of one leaf from the affected tree showing a yellow 'oak leafvein-banding pattern Plate 18 Betula alleghaniensts leaves showing chlorotic vein banding and concentric ring patterns associated with apple mosaic virus.

Plate 19 Betula papynfera leaves centre and right) showing yellow ring and line patterns associated with apple mosaic virus, leaf at left healthy. Plate 22 Leaves of Betula verrucosa naturally infected with cherry leaf roll virus and showing yellow ring and vein banding patterns.

Plate 25 Witches' broom in Carya pecan (Pecan bunch). Plate 27 Clematis (unnamed cultivar) showing yellow ring and line patterns associated with cucumber mosaic virus.

Plate 28 Cornus sanguinea leaves showing yellow ring and line pattern symptoms associated but not consistently with mixtures of tomato bushy stunt and cherry leaf roll viruses. * — - Plate 29 Cory lus aye/lane leaf showing yellow 'targetspot symptom associated with an ilarvirus serologically resemblino apple mosaic. Somewhat similar symptoms have also been associated with the distinct tulare apple mosaic virus. However, in other insarices hazel with these symptoms have consistently failed to yield any virus.

Plate 30 Leaf of Crataegus wattlana showing chiorotic ring and line patterns associated with a graft transmissible agent. No, Plate 32 Daphne odora foliage showing general chlorosis associated with two viruses, arabis mosaic and cucumber mosaic.

Plate 33 Euonymus microphyllus foliage showing yellow blotch symptoms when infected with cucumber mosaic virus. Plate 35 Fici mosaic disease symptom in a leaf of an unknown cultivar.

Plate 37 Leaflet of Fraxinus excelsior naturally infected with arabis mosaic virus and showing a chlorotic line pattern symptom. P/are 42 Ash wly-b droor 4. nos amency,na showing foliar chlorosis, diminished leaf s ze and branch oroWerattch ground lab-, he;_t,Ithe

• Plate 42a Chiona.,7/./.n. nis ormis rootsi .cl< showing yellow ring symptoms in foliage ass->ciftLed wdh tobacco rattle \Ares. Plate 43 Leaves of Hedera helix showing yellow vein banding and blotch patterns when naturally infected with art:as mosaic in combination with strawberry latent ringspof viruses.

Plate 44 Jasminum officmale foliage showing yellow blotch patterns when naturally infected with arabis mosaic viais. Plato 46a foolaris !try/a foliage showing in Southern Italy chrome yellow mottle associated with cherry leaf roll virus.

Plato 46 Juglaos fegta f oliage shoiediig chiciotic ring patterns when naturally infected with cherry leaf roll virus. The infected tree was a seedling onginasiiig irom imported seed end it in noteworthy that this chlorotic syndrome is also frequent in walnuts growing in Italy. Plate 48 Leaf ot Popu eLval-884cana Hut Sul natu! any niodieu spot symptoms.

Plate 53 Leaves of the rose cu ar Queen Elizabeth showing yeliow ring and ane patterns of rose mosaw with ilarvirus infection. A r , AO° 0.11" foi

to. j A ilAIL Ate Plate 55 Sambo;:us [2/gye tight) general pallor associated wrth arabis mosaic vms, Virus was nor gemected ga the bush on Ine lexr. w he

Plate 56a Yellow rigc ai clop cahrran:. or Sarnbtra.,a nigra foliage ,rifected with arabis mosaic virus. Typically . symptoms are expressed on only pg gio -ohage loL/ . supertioialk! healthy leaves contain virus. Plate 56b Leafi a ni ina FlaL al' v niecieci vv t afabis mosaic V ros and showing yellow neL symprohn been associated with ses.

Plate 58a Sorbus aucuparla leaf showing fine yellow ring and line pattern symptoms when naturally infected with a crcifi.'gens sibie agent resembling apple chloretic leaf sbot Plate 58b Leaves of Spraea douglas4 natui ally infected with arabis mosaic virus and s,lowingF veh/yeilovviri;:i on lopi arid out growths (enations) on the lower surfaces.

Plate 64 Viburnum lantana showing red tinged yellow line patterns n leaves : associated w th alfalfa mosaic virus. • =T. a.-renraria c rrarro;)!--)1 a , ) and 0055:0 . •1, 7tu)s. sot) -s reported y graft transmissibIe ::KLastersK. 1951:: Ho Ae.:er, beta:Is of ).-e exoehrents were fe.t, a- d. as ote.ti e se wbere. :Isee format:Dr otner workers bave faiIed to obtain transm:ssion of the cc:no ton bv grafting Fror Czech;s'ovakia, cur a,so from lta :t 5 reported Mat a cond•Lon affecting T. cordara assoc:ated wit't dwarfed foi,age. mrervemaI mom, ing and dieback) was transmitted by bark parch drafting (BIattny. 1938).

References BaTtr)a). C. (1938). Virova cooroba maly iist) a poharkevitast gstu 110y. Ochr. Rost. 14 80-81 • Klastersky. I. (1951) (A cowl forming afirnsIs in roses lime yees Pta(a CO—Leaves of LlImus glabra naturally infected with elm and elm Trees). Stadia bat csl 12 73-121 a-atge virus and sac Ning (at left) blotches and (at right) line r...alE:rn symptoms. U LM US—Ulmaceae uishable in other ways. Thus, an isolate from S Foliage diseases vulgans caused oak-leaf chlorotic line patterns in leaves of Buddleja davidn Franch after mechanical SYMPTOMS: Elm Mottle (Ulmenscheckung). Bright inoculation whereas one from Ulmus did not yellow spots, rings or stripes: no necrosis (Schmelzer, (Schmelzer. 1969) It is unfortunately not recorded et al, 1966). whether this species was infected byUlmus isolates. Distribution Atanasoff (1935) described symptoms in unspecified Ulmus growing in Bulgaria SYMPTOMS . Elm stripe (Ulmenstreifung). As elm Schmelzer (1969) cited authorities who recorded mottle but. in addition. chlorotic or necrotic oak leaf elm mottle disease in Czechoslovakia, UK, and the line patterns and stripes along the midrib of leaves may U.S.S.R. and Bojansky (1969) reported that elm occur (Schmelzer et al. 1966). mottle was one of the symptoms occurring together Distribution . In East Germany affecting U. glabra with witches' broom in East Germany. Species Transmission Not recorded. Sap transmission affected include Ulmus glabra L. and U. carpimfolia tests revealed elm mottle virus in material with Gled. these symptoms. Electron microscopic examina- Transmission : In spring/summer, Schmelzer tion of elm sap showed flexuous rod-shaped virus- (1969) transmitted a virus to -herbaceous hosts- like particles about 750 nm in length (Schmelzer, by mechanical inoculation but success was infre- 1969) quent. Jones and Mayo (1973) similarly isolated Causal agent/Relationship • Not known virus from Scottish U. glabra. A Scottish isolate of elm mottle virus was returned to U. glabra seed- SYMPTOMS : Elm mosaic symptoms reportedly vary lings by mechanical inoculation with sap from in- but it is probable that most observations have been fected herbaceous hosts but the characteristic made on trees simultaneously affected by several symptoms of the disease were not observed in these different pathogens. Whereas some leaves on an affec- plants during a period of twelve months in a heated ted tree may be normal in size, colour and texture, glasshouse (Jones and Mayo, 1973). others may be abnormally large and dark green or small, Elm mottle virus is seed-borne in naturally infected stiff, mottled and distorted. Smaller leaves may show U. glabra and was detected in pollen from another yellow-green mottle or yellow mottling along midribs naturally infected host (Svringa vulgaos L.) and in a few instances yellow or chlorotic ringspot Although Schmelzer (1969) indicated that tests to symptoms. Subsequently, leaf buds may fail to expand assess whether elm mottle virus was transmitted in leaving branches bare. Swingle et al, (1941: 1943) elm pollen were then in progress, the results have also commented that whereas elm mosaic disease was not been noticed. not associated with discolouration of bark or wood, Causal agent/Relationship Both the Scottish and these tissues on affected trees tend to be dry and brittle East German virus isolates had antigenic determin- and difficult to separate one from another. In U. ants in common but the extent of their serological amencana L. Ford et al, (1972) recognized an additional relatedness was not assessed. Although serologic- symptom—enations—associated with the disease. It is ally unrelated, the particle properties of a Scottish noteworthy that the original description of elm mosaic isolate were in some respects similar to those of disease (Swingle et al, 1941) included the phrase tobacco streak (Fulton, 1971) and prunus necrotic -mild to moderate brooming of branches-. This des- nngspot viruses (Fulton. 1970; Jones and Mayo, cribes a symptom characteristic of MLO—associated 1973). Virus isolates from East German Litmus elm witches' broom. Furthermore, about half (46 .6%) and from white mosaic-affected S. vulgans cross of trees in which zonate canker was recognised to protected against one another but were disting- occur showed foliage symptoms attributed by Swingle

61 11, 1 It \Ad

Plate 67—Elm zonate canker, symptom in Litmus americana with (left) and without (right) bark removed. Concentric ridges are apparent on the bark. et al, (1941) to elm mosa c drsease Parts of the syn- elm mosaic diseased trees to °herbaceous hosts-. drome described as elm mosaic closely resemble eHs Although tills virus was subsequently named elm mottle and elm stope diseases. mosaic virus. Varney and Moore were unable to infect elm seedlings when the seed coats were I n - Distribution : Elm mosaic disease is recorded ons o c u l a t e d with sap from the infected herbaceous from the U S.A. (Iowa, Oriro, Kentucky, Methygan, plants. However. Ford et al, (1972) induced New Jersey and Wisconsin) and affects LI symptoms they cons.dered typical of elm mosaic amencana. d.sease :n seed ings of II. americana inoculated (1941 1943) de- Transmiss0zn: Swingle et al, with sap from "'herbaceous hosts- contain na a monstrated the graft transmissasility of tl e elm virus isolated from a Mane form of U. amencaria mosaic agent: whereas none of flve attempts at growing in Iowa. transnsssion via root grafts (whicst uniteo) was Some natural spread of elm mosaic disease was successful, twenty of twenty plants io wasch barx reported in the earn: literature (Swindie er at, patch grafts were used became oReased In some 1943.) bit since then, there nave been nia plants, the whole syndrome of elm rcosac s-bstanca: data raub shed or • •he pattern ane deve;oced others hrs.: ;he col cr. extent of spread. Nevertheess, a consideraLe nngspot symptom The majority of host stocks esuwledge of possible vector agenc:es das accumu- developed a yellow-green mottle Only one tree lated. Bretz (1950) reported 1-3.5% seed trans- produced the ,,satches. broom effezt These ob zoss,on of elm mos{qc disease and Callahan (1957a servations were unfortunately not recorded in b) showed that this couid occur through pollen detail hut it is tempting to speculate that two (er However, there was co evidence that indeed three) distinct agents may have been trees became infected by ocIllnat,on z :nfected separated or bast ally senarated by the graft nd [1,D les. experiments. In a short paper. Ca lahan (1963) repoHed the Causal agent/Relationship. The elm mosaic virus transmission by inocust on of sap of elm mosax: sotate transmitted by Varnev and Moote 11952) from diseased to heaztv tlanos rgs.o. Far' ex xs, general preazeofies v\pth tnnrcik.k Varney and Moore (,1 952) vas troqed wrus 4. a.

! ! I .4.ft•

V.?!

446.,45

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.!' ]:1,, r:' !rn r r.1,11..L'as,".;/;( uted M! Stem diseases and supporting evidence for this view may come from Gualaccini (1963) who reported that agents causing SYMPTOMS : Elm zonate canker. This disease has not cowl symptoms were not graft transmitted. Histological been seen in naturally affected trees and significantly observations on twigs affected by witches' broom was noted in grafted stock in which Swingle and Bretz disease revealed greatly diminished phellogen and (1950) recognized an additional syndrome which they phelloderm and, when leaves were examined, the attributed to elm mosaic. Therefore, it must be borne palisade cells were observed to be abnormally short in mind that the observations they recorded may be the and broad making difficult their distinction from spongy result of two or more pathogens in combination. Some mesophyll. affected plants showed mottling and necrotic spotting symptoms in their spring foliage. Distribution : Czechoslovakia (where it is repor- In a few instances concentric, slightly raised rings of tedly common, Bojansky, 1969), UK (Jones and alternately light and dark tissue developed on the Cooper, unpublished data) and from Italy (Gualac- surface of bark in young branches. These enlarged into cini, 1963) : However, symptom expression seems dry necrotic bark cankers which extended to affect greatly affected by environmental factors (branches cambium as well as xylem tissues, killing parts of the with symptoms at one time of the year may recover trees by girdling. On branches at levels below where to show normal growth) and it seems probable that grafts were inserted, leaves showed brown necrotic the disease is present elsewhere. spots which coalesced to cause parts of the laminae to Transmission : Transmission between U. carpini- collapse. folia by Means of budding has been recorded but the range of symptoms which developed in inoc- Distribution : Although the zonate canker form of ulated trees have not been fully described. It is this disease has not been recorded at present out- interesting to note that Gualaccini (1963) reported side the USA, it is noteworthy that leaf symptoms graft transmission of witches' broom agents to similar to the necrotic collapse, described and Robinia pseudoacacia L. in addition to U. pumila L. illustrated in U. americana by Swingle and Bretz (1950) have been noted in .U. glabra and U. Causal a ent/Relationshi : Not known. carpinifolia from Czechoslovakia (Svbodova, 1963 ; cited in Schmelzer, 1968). SYMPTOMS : Elm phloem necrosis. Drooping and curling of leaves becoming yellow then brown before Transmission : The disease developed in apparently falling. In many instances, trees showing overt signs of healthy nursery trees to which bark patch grafts the disease in spring died during the same summer. from trees showing abnormally severe symptoms When exposed, the inner bark tissue reportedly exudes of elm mosaic disease had been applied. There is an odour of wintergreen and may show a butterscotch evidence that the condition may be latent in Ulmus colour darkening to black-brown (Swingle et al.,1949). because cankers developed in trees grafted with Phloem necrosis affects root tissue too ; fibrous roots bark patches from seven of fifteen symptomless die soon after infection, hypertrophy and hyperplasia of trees. parenchyma occurring in the phloem of older roots and The leaf necrosis reported to accompany zonate the stem (McLean, 1944). canker formation did not develop in foliage of twenty U. americana to which leaf sap had been Distribution : Elm phloem necrosis is not known to manually inoculated. occur in countries other than USA where in some Causal agent/Relationship : None known. Myco- years and in some localities the disease has been logical investigations did not reveal any consistent implicated in the death of 75% of elms (Seliskar, association of the cankers with visible organisms. 1966). Hepting (1971) stated that in some cities Swingle and Bretz (1950) commented on the of the Midwestern states more elms are killed by similarities (having regard to the graft transmission phloem necrosis than by the closely similar Dutch via bark patches) with Pierce's disease of grape- elm disease which has a different cause, the fungus vines which is now associated with RLO (Goheen Ceratocystis ulmi (Buism.) C. Moreau. et al, 1973). Traditionally, elm phloem necrosis was observed only within the region of the Great Plains east- SYMPTOMS : Elm witches' broom. In U. carpinifolia wards to West Virginia and south to the Mississippi they included chlorotic leaves of abnormally small size (Bretz and Swingle, 1946 ; Swingle et al., 1949), and which tend to be borne on twigs with short inter- but the disease was more recently recorded from nodes : affected twigs dieback and trees may progress- Pennsylvania (Sinclair et al., 1971 ; Sinclair, 1972). ively wither and die (Bojansky 1969). In many in- Transmission : Readily obtained by budding or stances, cowl-forming leaves (Klatersky, 1951) may be grafting albeit with a somewhat variable incubation seen at the proximal ends of twigs on affected trees. period before symptoms develop (1-24 months). Cowl-formation, the twisting of the lamina around the Attempts to transmit the disease to herbaceous midrib to form a cone, has been reported in leaves of plants by mechanical inoculation of leaves with several trees and shrubs growing in Eastern Europe but phloem exudates or leaf extracts were unsuccessful only one attempt at transmission by grafting and none (Thornberry, 1958). In a series of papers, Baker otherwise are reported. Bojansky (1969) suggested (1948, 1949) and others showed that nymphal that cowl formation is a "teratological phenomenon" leafhoppers (Scaphoides luteolus Van Duzee)

64 á Fulton. J 1-Talid Ftjir,.en R 1l (19701 St, • oubdnison L-t soma VIBURNUM—Caprifoliaceae plopeItie ul elm mortars end ktresto ringueyt viruses Pe, To- par/re/es/a 60, I 14-115 See plate 64 (Colour) Fulton R Vvt [10,/iTy brunt's 110010510 [muslin!, \awn 011 Foliage disease

Fulton R W.11971) TUDaCCL, stNiak dirus nI r); 4.13 ap, P18/71 V Inist.,5' no 44 4 pp, SYN1PI OMS Variegation, light green to white patches. Goheen, A Wang 0. and Lewe S.K (111731 Assaciatiye vein yellowing and necrosis a rickettsia like urgernsm with Pierce s oiseasn of grapevines aw) alfalfa dwarf and Peat thews ef the giscaSe ni :rapeyifles Distribution I East Germany. Czechoslovakia and Phytopathoiboy 63. 341-345. Hungary (Schme7er and Schmidt, 1960) affectmg Guallacciia, (1903) Primi resultati di espeuenza sa se:spawn Vibernwi, ()pules Affectmg V. tmus L. in oglie ao unouto ea altru ark:made pall olny, campestre (lJeyer. Yugoslavia. Italy, France (('lese and MIlicica 1971). Pd(0.1 Rerld 21 Soy 31 25 43 OBIlipeStILS L4 Boil. Stan the USA. (Schwenk et al.. 1969) and the UK plus Hepting 119. 1). Diseases or lerekt and shade Pees tse V lantana L UK (Cooper, unpublished data) Ornted States, Agee. Hindtt. LI 5. 00p6 Agnc 086 and Eas; Germany (Schmelzer, 1966) Pierces diseake uf grape (pries Cap Col!, . Pop: Len Po) Transmissmn In sap tc -herbaceous hosts.' and _Fries A.T (1973r A comparison ot some ).iryheree, 111f with aphids (Myzus persvcae Sulz. and ApIns strains or cnerry ledf LAI virus Ann appl BILE 74 111-21 / Tones A T and May,. M A (1973) Puuticati (r) snd rtturrren.), tobern, scop.). et elm mottle virus Ann. appi B/el 75 347 35/ Causal agent/Relationship I There are only two Junes. A» er u Murant, Aid (19711 See ks[i esati nyen, repents of testk to satisfy KochLs postulates: the between eFerry leaf 1011elm reesacs and yulden el-Tenter.: 01)eriss diseases ILI V otatihis and V. tnno; were reproduced Ann moil B pi 69 11 14. Klasterskv L 11051) 1.4)cowl fnmund kiresis Ifl r. aes Inns trees followInt1 tne inanwation of seedlings wqh alfalfa and elm trees 1/ SrLidia her. CS1 12 /3-121 runsain S. All isolate of alfalfa nosaic virus McLean D M 61944r. Histu ;pinup:Fay thnnaus the • t 'From I/. tines possessed a protein cuat with novel p ;9 ertHs (Conger 1976) Pnympotlipipgy 34 818-8.16,

Clarandon Press i.51 Raper: -.! OW a re Sshertazer, K. (1958) Lier ForSI mill tOi Tarestr. Institute Onrran 27 lanzhono Voulpoic edited by M. KlinkYaiski yid 2,222 303. Berlin ( Akaderyie-Venag 111eseN. r Miry D 119/ 1 Fuzereascssis-vires Viournum Sehmelzer. K. (1969). Das Ulmenscheckenus Virus Pnytop,P Z. 64, 30-01i. Schmelzer, K. (16721 Dau Kirseenblettroll saus age ner 854 (Betide pendolo Roti ..) Vial. B4kl PanasakOu Ant 127, 0 s S. and Scumidt. H 0.119601. Untersuchungen dber Schmelzer . K Schmidt, H E und Schmid: H [10061 %aids Siilimelder. K. krankheiten und yirusyereaChtIde Ersolierbincten dii r ingdo- 417-4130 holden Aron 1-01151."/ 15. 107-100 Seliskar, C.E. 09661ADrILIFRO Symposium un internatideae, dangerous forest diseases fat inseets 44, Oxford 1964 (rt L' FORPEST 64-5.19661 Sinclair . %Ai (1972)Phiotere nocIesis of Anserlean ses )I.: elms irs New York Pi as Acetr 56. 159 1 el Sinclair . S'y A, Camparyd, R Marrin P O :r. ed E sed Nicnois, L (1971). Elm phlaem rietrasis ii Pew sips Pi as Repo- 55, 1085 Swersjie, P.O. and Bretz I 'Iv (19601 Lasate cakko CI sass disease of Anierican elm Par,I:teach 'Flog,/ 40 1018 1021 Swindle, Rid. Mayer h and Mad. Cs)(10.11) Pleoem researcn during 1944 Pi:yn.s.oaci olegv 35, TV Sayingla, R Tilford P F. Ted disk C 11141 ir I mosaic of Amer warn elm Pr y repotholA;; 31 22 Seringle R U. Tilford, P± and Irish b F (1943) I b nussible MesoIC id American elm Ph vro;;;dt,'30»:“7, 33 i Swingle P.O. Vvitten R Ted \towed H.1..1T40r. 1 so irldneli cdtion spd evr.trs I of elm' phloem netaynins a"d iuntb clibosst

Thornberrd, 11.8. (19580R nsetnesi f isclatir g weds li[e. particles tbtab ssegaril ralants snowy61 SyndatbmS p' urn nettrosis, peabri x-disease and cherry hegsplit. Pp. rp(nor!.L.Po , 48, 15-19 Varney . E U. and Moore T (1952), Styyn a' Ireland ne Rust virus from American elm. Pi: 2tupoino/7:27,, 42 476-7, Walkey, D.G A , Stace-Sentn, P. and Tram:line, J . i 1 619731, Serological, physical and seerracal :Pupa:rues _f strdres H _Ten. leaf roll virus. P4incottoiepv 63 566-67 P,ramp65— iourripm unp leaves sheaang ch re Me kellgav reissible viruses ot American elm Pr De) Rear; 43, L patte[cs assTryated sote alfalfa mosaic virus Pre virus infetytod 1711 :Joy— \Arilbon Seliskar G.E. ana Fr tasey1, R becIIIto. V. Prras' seedlings hut cid nut cause symptoms durekd like bcdies associated enn elm piiinern re_;u3IS Pr ..rogn:' a' - sensequeet s year period, 62 140-143. WISTARIA—Leguminosae Examination of the available data does raise, two questions. Why are 'specialist' tree viruses seemingly Foliage disease infrequent and why are 'opportunistsrelatively common ? There are probably many reasons but most im- SYMPTOMS : Yellow-pale green blotches, vein yellow- portant. the detection of virus-associated diseases ing lateral twisting and malformation of leaves. depends on the availability of virologists and these may be in the wrong places. The study of viruses requires Distribution : In the USA (Brierley and Lorentz, costly analytical and measuring instruments, conse- 1957) in Italy, Bulgaria, East Germany and the quently, most is known about viruses of plants grown Netherlands (Lovisolo, 1960, cited in Schmelzer, in the countries of Western Europe, North America. and 1968) and probably whenever Wistaria floribunda much more recently in Japan and Australasia. D.C. is grown. Transmission : By grafting to W. sinensis Sweet It seems axiomatic that highly adapted pathogens such (Brierley and Lorentz, 1957) and in sap to "herbas viruses evolved through long association with their aceous hosts" (Bos, 1970). hosts. Thus, all but a few of the potato viruses (about Causal agent/Relationship : The isolates Bos ob- thirty known) seem to have come with planting stock tained had properties in common with members of from the centres of species diversity in the Solananceae the potyvirus group. Mueller (1967) detected (namely the Andean regions of South America) to tobacco mosaic virus in W. sinensis with chlorotic countries in which S. tuberosurn is now cultivated as leaf spotting symptoms but inoculation of healthy a food crop. The exceptions are the 'opportunists' Wistaria spp. with the isolate did not cause alfalfa mosaic, cucumber mosaic, tomato black ring, symptoms. tobacco necrosis and tobacco rattle viruses.

References Amenity trees grow in greater variety in UK than al- Bos, L. (1970). The identification of three new viruses isolated most anywhere else in the temperate world. However, Pisum in the Netherlands and the problem of from Wisteria and the species diversity is artificial. Fewer than fifty are variation within the potato virus Y group. Neth. J. Pl. Path. 76, 38-46. native to Britain (Clapham, Tutin and Warburg, 1962), Brierley, P. and Lorentz, P. (1957). Wisteria mosaic and peony and only a handful occur wild exclusively in the UK. leaf curl, two diseases of ornamental plants caused by virus Europe in general, the UK in particular and North America transmissible by grafting but not by sap inoculation. Pl. Dis. to a lesser extent, have a greatly enriched tree flora as a Reptr 41, 691-693. consequence of introductions made from diverse and Mueller, W.C. (1967). Tobacco mosaic virus obtained from diseased Wisteria and elder. Pl. Dis. Reptr. 51,1053. often very restricted natural populations. A realistic Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In : estimate of potentially damaging viruses may only be Pflanzliche Virologie edited by M. Klinkowski. vol. 2 part 2, obtained when detailed research into tree and shrub 232-303. Berlin: Akademie-Verlag. viruses is done in the remote regions of the Andes, China, the Himalayas, etc., from which the plants came. There are other possible explanations. Perhaps as Thresh (1974) implied, trees and shrubs are inherently Conclusion more resistant to virus infection than other plants. Alternatively, the comparative scarcity of unusual and Until now, knowledge of viruses infecting trees and distinct viruses recorded to date in European and North shrubs has been based on speculative investigations American trees and shrubs may be due to the fact that made after the accidental discovery of a virus-like when introductions were made, only a few specimens disease which seemed to justify part-time research. (by chance free from virus infections) formed the Therefore, it is likely that the viruses detected represent nucleus of the stock which now exists. In some in- only the tip of an iceberg ; many others await discovery stances this may have been because seed having a and it is premature to discuss in detail the significance smaller risk of virus infection than growing plants was of the available data. It is, however, noticeable in the foundation. In any event, the available information Table 1, p. 19, that trees/shrubs with 'sappy' leaves e.g. on virus incidence in trees and shrubs is consistent with Ulmus. Sambucus and species in the Oleaceae are the relatively recent exposure of initially healthy and for known hosts to more viruses than trees with thin, dry, the most part widely scattered plants to a range of brittle leaves, e.g. Quercus, Fagus and Acer. Perhaps 'opportunist' viruses. One might anticipate that the this only reflects the greater ease of transmission from effects of these and other viruses will become more soft foliage. However, future work may show that this apparent with the expansion of managed plantations/ difference is not real, or is due to some other property. forests which are more suitable for rapid virus spread Similarly, data are too few to justify the assertion that because they consist of one plant species in large plants in the families Caprifoliaceae, Leguminosae, numbers and all at a similar stage of growth. Thus, al- Oleaceae and Saxifragaceae are more prone to infection though it now seems likely that all but a few of the by viruses than trees and shrubs in other families (Table potato viruses were imported into Europe with planting 2, p. 68) but it is tempting to speculate that their leaves stock, historical evidence, reviewed by Salaman (1949) may be found to contain lesser amounts of chemicals and van der Plank (1949), suggests that the non- which impede detection (usually mechanical trans- persistent aphid borne potato viruses Y and A became mission) of viruses which are present. prevalent about 1770 whereas the contact—spread

67 Table 2. Vector routes, where known, of some well characterized viruses detected in tree/shrub families.

In the soil In the air by aphids Host family by Nematodes other non-persistent

Aceraceae AMV Aquifoliaceae TobRSV Araliaceae AMV SLRV Aristolochiaceae AMV CMV Berberidaceae cmy Betulaceae CLRV TRV TNV Buxaceae AMV Bignoniaceae BBW Calycanthaceae Caprifoliaceae AMV SLRV CLRV TobRSV TomRSV TBRV TNV CMV LMV Celestraceae SLRV TBRV TNV CMV Cistaceae LMV Cornaceae AMV CLRV TobRSV TomRSV TBSV CMV BBW Fagaceae TBRV Hippocastanaceae SLRV Juglandaceae CLRV Labiatae LMV Leguminosae AMV SLRV TBRV CMV RoMV BYMV Loganiaceae SLRV CMV Magnoliaceae CMV Malvaceae Moraceae MuIRSV Myrticeae Oleaceae AMV SLRV CLRV TobRSV RRV TBRV TRV TBSV CMV LMV Onagranaceae Papaveraceae CMV Passifloraceae CMV PFW Pinaceae AMV TomRSV TBRV TNV Pittosporaceae Ranunculaceae TRV CMV Rhamnaceae CMV LMV Rosaceae AMV SLRV TobRSV TomRSV Rutaceae AMV CLRV TobRSV Salicaceae AMV RRV TNV Saxifragaceae AMV TobRSV TomRSV TBRV TRV TNV CMV LMV Scrophulariaceae CMV LMV BBW Solanaceae CMV Staphyleaceae AMV TBRV Taxaceae Thymelaeceae AMV TobRSV TBRV CMV LMV Tiliaceae Ulmaceae CLRV Verbenaceae TBRV LMV

Nematode-borne viruses with polyhedral particles AMV arabis mosaic virus RRV raspberry ringspot virus SLRV strawberry latent ringspot virus TBRV tomato black ring virus CLRV cherry leaf roll virus MuIRSV mulberry ringspot virus TobRSV tobacco ringspot virus TRV tobacco rattle virus TomRSV tomato ringspot virus

Other soil-borne viruses TNV tobacco necrosis virus TBSV tomato bushy stunt virus

Aphid-borne viruses CMV cucumber mosaic virus LMV alfalfa (lucerne) mosaic virus BBW broadbean wilt virus RoMV robinia true mosaic PFW passion fruit woodiness virus BYMV bean yellow mosaic virus

68 Initially healthy weed

Infected seed Virus free seed

Virus i. infected weed

Virus Initially Infected tree healthy tree seedling seedling

Virus infected weed

Initially healthy crop plant

Plate 66 —Diagram indicating some of the pathways of virus spread and the possible involvement of trees and shrubs.

potato virus X and the 'specialistpersistently aphid- rather than weeds or herbaceous crops (Thomas, 1970), transmitted leaf roll virus were not widespread until it is premature to deduce that nepoviruses generally about 1904 even though probably locally important have some intrinsic preference for woody hosts. Thus, before this date. Perhaps this was because the potato tomato black ring and raspberry ringspot viruses, with crop was much more continuous in its distribution by Longidorus vectors, have to date been detected some- this time, thereby facilitating epidemic virus spread. what less frequently than arabis mosaic, tomato and It is noteworthy that the incidence of infection with tobacco ringspot. Perhaps this is because longidorids viruses having aerial vectors tends to diminish when tend to be associated with shallow rooted herbaceous susceptible crops are closely planted. Furthermore, crops rather than tree roots (Lamberti, Taylor and individuals in mixed plant communities usually have a Seinhorst, 1975). lower virus incidence than those in similar pure stands. Cherry leaf roll virus isolates have properties in com- The practice of growing hardy nursery stock in mono mon with nepoviruses but differ from other members culture at wide spacing surrounded by soil kept weed of the group in being a collection of "specialists" free by herbicides or cultivation may tend to facilitate with a predelection for woody hosts. Serological infection. tests chiefly measure changes in one property of a virus particle, its protein coat, and in other circum- Although the incidence of 'specialist' tree viruses like stances might not be given undue weight. How- poplar mosaic and robinia true mosaic is unexpectedly ever, specific transmission by vectors is likely to low, it is apparent from Tables 1 and 2 that viruses with require adsorption of virus particles to vector surfaces, polyhedral particles and nematode vectors have been and adsorption will be greatly affected by properties of detected very frequently in leaves of broadleaved trees the protein coat. Consequently, a brief discussion of and in the roots of conifers. Nepoviruses (Harrison and comparative serology has ecological/epidemiological Murant, 1977) are readily mechanically transmitted in relevance. Antigenic variations between cherry leaf sap to "herbaceous hosts", being somewhat more roll virus isolates from the same or closely related hosts stable and reaching higher concentrations than many have, but infrequently, been noted (Schmelzer, 1972; others. This combination of properties has favoured Walkey, Stace-Smith and Tremaine, 1973; Waterworth their detection and, although Xinhinema spp. (e.g. X. and Lawson, 1973 ; Savino et al., 1977). Notwith- diversicaudatum transmitting arabis mosaic virus) standing the report suggesting that two Yugoslavian multiply relatively more on woody perennial hosts isolates of cherry leaf roll virus from Sambucus nigra

69 and S. racemosa had few, if any, of their antigenic entering the country, not only for amenity use by determinants not held in common (Grbelja, 1972) municipal authorities, but also for domestic garden somewhat greater serological differences are more planting. Sometimes rootstocks are imported, such as typical, as when isolates including those from Betula, Rosa rugosa. In other instances, named varieties that Cornus, Jug lans, Ligustrum, Ptelea, Prunus, Sambucus have been grafted onto rootstocks are introduced and Ulmus were compared (Cooper and Atkinson, complete. Many, perhaps all, horticultural forms of 1975 ; Jones, 1976 ; Schmelzer, 1972). Significantly, Acer and Fraxinus spp. are budded in the UK into Acer although Prunus isolates of cherry leaf roll virus have pseudoplatanus or Fraxinus excelsior rootstocks and, in been reportedly transmitted by Xiphinema spp. (Fritz- most instances, these rootstocksare seedlings. In any sche and Kegler, 1964 ; Flegg, 1969 ; McElroy and event the plants are generally imported in a dormant Jones, cited in Jones, 1976) the efficiency is low and, condition when visual inspection to detect virus-like since Fulton and Fulton (1970) did not detect trans- symptoms is impossible. Strange though it may seem, a mission of an elm isolate by X. americanum Cobb, it is great many indigenous species are not normally raised tempting to suggest that a highly genus specific vector from seed collected in the UK. Indeed, the normal agency such as pollen may be the most important, sources of rootstocks are rooted seedlings imported possibly the only method of plant-to-plant spread in through, but not necessarily originating in. Denmark, nature. Whereas in elm, walnut and birch, CLRV does the Netherlands or West Germany. Clearly, the im- not seem to spread with the aid of soil-inhabiting portation of indigenous species is not essential and, vectors, the virus is disseminated in seed (Callahan, even as seedlings, should be avoided because of the 1957a, b ; Lister and Murant, 1967 ; Tomlinson and attendant risks. Seed is relatively, but not by any means Walkey, 1 967; Schimanski and Schmelzer, 1972 completely (see Phatak, 1974 ; Neergaard, 1977), free Cooper, 1976 and Plate 23). When susceptible trees from phytosanitary threat. By contrast, rooted seed- having numerous flowers may be exposed to wind- lings inevitably bring with them soil in which they grew, borne inoculum for several centuries, virus spread might thereby offering opportunities for the importation of well depend upon very rare events, perhaps including non-indigenous soil-inhabiting pests and pathogens, virus transmission following interspecific or inter- such as types of the fungus Syncytrium endobioticum generic pollination. Worr. which are capable of causing wart disease in potato cultivars immune to the fungus present in UK. Although viruses require a continuous supply of hosts As far as is known, virus-vector nematodes occurring in which they can grow and must frequently spread to in the exporting countries also occur in the UK. How- infect new hosts if these are ephemeral, the pressure to ever, it is worth noting that studies of nematode- find a new home is somewhat less strong when the host transmitted viruses have shown that the reassortment is perennial. The infrequency of observed differences of genetic material between two viruses present in one between arabis mosaic and tomato ringspot virus iso- host can occur (Harrison et al., 1974) and the possi- lates from different host genera/species and locations bility cannot be excluded that exotic virus strains may suggests that the mobility of highly polyphagous be introduced into the UK in woody planting stock. vectors is the most important factor, allowing frequent interchange of viral genetic material (out breeding) Until planting stock free of known viruses is available between diverse virus populations in weeds, crops, for comparison, it will continue to be difficult to trees, etc. (Plate 66). The same is probably true for quantify loss due to virus infection of trees. However, viruses such as cucumber and alfalfa mosaic which it is not difficult to appraise the position that forest and have non-persistent relationships with their omni- shade trees occupy in virus ecology. It is apparent even vorous vector aphids. Seed and pollen transmission in this rudimentary state of virology that woody tends to stabilize (by inbreeding) virus populations, perennials are potential reservoirs of pathogens for facilitating spread but at the expense of diversity. At all plants growing in their vicinity. Consequently, trees stages in virus replication, mutations may produce new warrant more detailed attention than they have been types, differing from the parental viruses in properties awarded hitherto, the aim being to free them from having consequential effects on vector relationships. viruses, thereby increasing their productivity and In some instances, the ability to be transmitted by environmental benefit, and at the same time lessening vectors will only be diminished, in other instances lost, the hazard they pose to adjacent crops. and the viruses will thereafter depend for their survival on seed, pollen and vegetative propagation of the infected host. Because of their longevity, trees and shrubs References might well be repositories for numerous 'fossil' viruses Callahan, K.L. (1957a). Pollen transmission of elm mosaic virus. having unusual properties. It will be interesting to Phytopathology 47, 5. Callahan, K.L. (1957b). Prunus host range and pollen trans- see whether 'future research shows that woody mission of elm mosaic virus. Dissertation Abstracts 17, 1861. perennials generally contain a greater range of distinct Clapham, A.R., Tutin, T.G. and Warburg, E.G. (1962). Flora of viruses than do plants with shorter life spans and in the British Isles. 2nd Edition. Cambridge : Cambridge Uni- which vector transmission may be assumed to play a versity Press. more essential role in virus survival. Cooper, J.I. (1976). The possible epidemiological significance of pollen and seed transmission in the cherry leaf roll virusl Betula spp., complex. Mitteilungen aus der Biologischen Bundessan- Woody perennials are now being imported into the UK stalt fur Land-und Forst-wirtschaft. 170, 17-22. on an unprecedented scale. Trees and shrubs are Cooper, J.I. and Atkinson, M.A. (1975). Cherry leaf roll virus

70 causing a disease of Betu la spp. in the United Kingdom. Forestry. Plank, J.E. van der (1949). Some suggestions on the history of 48, 193-203. potato virus X. J. Linn. Soc. (Bot.) 53, 251-262. Flegg. J.J.M. (1969). Tests with potential nematode vectors of Salaman, R.N. (1949). Some notes on the history of curl. cherry leaf roll virus. Rep. E. Mailing Res..SIII. 1968. p. 155. Tijdschr. PIZiekt 55, 118- 128. Fritzsche. R. and Kegler. H. (1964). Die Ubertragang des Savino. V., Ctuacguarelli, A., Gallitelli, D.. Piazzola, P. and Blattrollvirus der Kirsche (cherry leaf roll virus) durch Nematoden. Martelli. G.P. (1977). II virus dell'accartocciamento fogliare del Naturwissenschaften 51. 299. Ciliegio nel Noce. I. Identificazione e caratterizzazione. Phyto- Fulton. J.P. and Fulton, R.W. (1970), A comparison of some pathologia Mediterranea, 16, 96- 102. properties of elm mosaic and tomato ringspot viruses. Phyto- Schimanski. H.H. and Schmelzer, K. (1972). (Contribution to the pathology. 60, 114- 115. knowledge of the transmissibility of cherry leaf roll virus by seeds Grbelja. J. (1972). (Distribution of elders (Sambucus nigra L. of Sambucus racemosa L.). Zbl. Bakt. ParasitKde. 127 Abt. and S. racemosa L.) infected with cherry leaf roll virus in Yugo- 673-675. slavia.) Acta Bot. Croat. 31, 29- 36. Schmelzer, K. (1972). Nachweis der Verwandtschaft zwischen Harrison. B.D. and Murant, A.F. (1977). Nepovirus group. Herkunften des Kirschen blatt roll-virus (cherry leaf roll virus) C.M.I./A.A.B. Descr. Plant Viruses, No. 185. und dem Ulmen mosaik-virus (elm mosaic virus). Zbl. Bakt. Harrison, B.D., Murant, A.F., Mayo. M.A. and Roberts, I.M. (1974). ParasitKde 127 Abt II, 140-144. Distribution of determinants for symptom production, host range Thomas, P.R. (1970). Host status of some plants for Xiphinema and nematode transmission between the two RNA components of diversicaudatum (Micol.) and their susceptibility to viruses raspberry ringspot virus. J. gen. Virol. 22, 233-247. transmitted by this species. Ann. appl. Biol. 65. 169-178. Jones, A.T. (1976). Serological specificity of isolates of cherry Thresh. J.M. (1974). Temporal patterns of virus spread. Ann. leaf roll virus from different natural hosts. 39/49. Agric. Con- Rev. Phytopathol. 12, 111- 128. spectus Cci. 39, 527- 532. Tomlinson, J.A. and Walkey, D.G.A. (1967). The isolation and Lamberti, F., Taylor, C.E. and Seinhorst, J.W. (1975). Nematode identification of rhubarb viruses occurring in Britain. Ann. appl. vectors of plant viruses. London and New York. Plenum Press., Biol. 59, 415- 427. Lister, R.M. and Murant, A.F. (1967). Seed transmission of Walkey. D.G.A., Stace-Smith, R. and Tremaine, J.H. (1973). nematode borne viruses. Ann. appl. Biol. 59. 49-62. Serological, physical and chemical properties of strains of cherry Neergaard, P. (1977). Seed Pathology. London : Macmillan leaf roll virus. Phytopathology, 63. 566-571. Press. Waterworth. H.E. and Lawson, R.H. (1973). Purification, Phatak, H.C. (1974). Seed-borne plant viruses-identification electron microscopy and serology of the dogwood ringspot strain and diagnosis in seed health testing. Seed Sci. and Technol. 2, of cherry leaf roll rirus. Phytopathology. 63, 141-146. 3-155.

G lossa ry

AETIOLOGY : Study of the origins and causes of diseases. ANTIGEN : A protein, or more rarely other types of molecules with large molecular weights, which when injected into living vertebrate animals cause the formation of 'new' specific proteins (antibodies). ANTISERUM : Serum containing antibodies produced by a vertebrate injected with antigen. BUDDING : A grafting method in which a bud is the scion. CLONE: A genetically 'uniform' line of plants derived from an individual (mother plant) by vegetative propagation. CROSS PROTECTION : The protection afforded when an earlier virus inoculation prevents the development of additional symptoms when followed by a second inoculation with a different virus. Cross protection is generally only given by closely related viruses, although somewhat less reliable when assessing relationships than serological tests (Fulton, 1978).* CULTIVAR (cv) : A genetically 'uniform' line of cultivated plants characterized by any agricultural/horticultural feature. DIFFERENTIAL HOST : A plant producing distinctive and diagnostic symptoms when infected by a particular agent (e.g. virus). FASCIATION : Incomplete separation of additional shoots (proliferation) giving the appearance of a flat bundle. GRAFT TRANSMISSION : Transmission of infectious agents from rootstocks to scions or vice versaafter grafting. Garner (1958)** described numerous methods of which 'approach' and 'detached scion' techniques are commonly used by virologists. In the former, the partners grow on their own roots whereas in the latter only one partner does. HERBACEOUS HOSTS : Plant species commonly used to detect viruses in sap when mechanically inoculating. The following are worthwhile :

*Fulton, R.W. (1978). Superinfection by strains of tobacco streak virus. Virology 85, 1-8. **Garner, R.J. (1958). The grafters handbook. London : Faber Er Faber.

(1) Chenopodiaceae C. quinoa Willd. C. amaranticolor Coste Reyn.

71 (2) Solanaceae Nicotiana tabacum L. N. clevelandii Gray N. glutinosa L. N. megalosiphon Heurck Muell.

(3) Leguminosae Phaseolus vulgaris L. Vigna sinensis L.

(4) Cucurbitaceae Cucumis sativus L.

IN VITRO : A term describing activities or experiments done in artificial conditions. Literally 'in glass' and generally used to describe laboratory experiments. IN VIVO : A term describing activities or experiments done in living host plants. Literally, 'in something which lives'. ISOLATE : The infectious preparation obtained from a susceptible host inoculated with sap from an infected plant. The term implies a functional unit that may contain more than one type of virus. KOCH'S POSTULATES : There are three : (a) consistent associations of a suspected agent with a disease syndrome. (b) isolation of the infectious agent (c) reproduction of the disease syndrome (a) after transmitting the infectious agent (b) to healthy hosts. N.B. The additional need to re-isolate the infectious agent (b) from the experimentally infected and diseased plant (c) was suggested by E. F. Smith. MECHANICAL TRANSMISSION : The transfer of viruses from one plant to another by friction the one rubbing against the other or more usually by artificially rubbing leaf sap, root extracts etc. from infectors to leaves of other hosts. MODAL LENGTH : Most frequently observed length of virus particles : a criterion used when grouping viruses having rod-shaped particles. NANOMETRE (nm) : =10-9 metre or 1/1,000,000 mm. SEROLOGY : The study of reactions between antigens and antibodies in the aqueous part of blood (serum) from immunized animals (usually rabbits, rats, mice, guinea pigs). Antigens and their complementary antibodies react specifically. Antibodies may neutralize the infectivity of a virus with or without causing the virus particles to form a visible aggregate that precipitates. SYSTEMIC SYMPTOMS : Symptoms occurring in parts of plants other than those actually inoculated. VIRUSES : Specific aggregations of two or more types of chemicals (usually nucleic acid surrounded by a proteinaceous coat) which are infectious and potentially able to cause disease. VIRUS NAMES : There is no universally accepted system of naming viruses. Fenner (1976)* defined twenty groups of viruses known only to multiply in vascular plants and a further two groups having members multiplying in both plants and inverte- brates. Additionally there are many plant viruses that have not yet been categorized similarly. WITCHES' BROOM : Unusually prolific groups of shoots. WOODY HOSTS (Indicators) : Species/cultivars of woody perennials commonly used for detecting graft- transmissible virus-like infectious agents. The following are sensitive and susceptible to appreciable ranges of infectious agents.

Cydonia oblonga Mill. cv 7/1 Malus purnila Mill. cv Lord Lamborne M 139 cv Spy 227 cv Virginia crab Malus platycarpa Rehd. Prunus aviurn L. cv Sam cv F 12/1 Prunus persicae (L.) Batsch. cv GF 305 Prunus serrulata Lindl. cv Shirofugen cv Kwanzan Pyrus communis L. cv A 20 Pyronia veitchii (Trabut.) Guillaumin.

*Fenner, F. (1976). Classification and nomenclature of viruses. Intervirology 7, pp 115.

72 Appendix

Some additional virus-like conditions with unknown or untested aetiology

Host Syndrome Reference Acacia spp. leaf mosaic Wiehe (1948) Acer sp. leaf vein banding Et ringspot Schmelzer et al. (1966) Acer sp. leaf deforming mosaic Et shothole necrosis Smolak (1949) Aesculus sp. stem spindle tumour Buchwald (1961)* Ailanthus sp. leaf mosaic Et rolling Svobodova (1963)* Albizzia sp. leaf mosaic Wiehe (1948) Alnus sp. leaf vein clearing Novak (1966) Calluna sp. dwarfing Er proliferation Svobodova (1963)* Carpinus sp. leaf deformation Er mosaic Ploaie Macovei (1968) Cassia spp. leaf mosaic Deighton Er Tinsley (1958) Castanea sp. dieback Kuhnholtz-Lordat (1944) Celtis sp. leaf curl Sibilia (1947) Cornus sp. dimpled fruit Atanasoff (1935) Cystis sp. leaf mosaic Eliade (1965)* Deuzia sp. leaf distortion Er mosaic Eliade (1965) * Erica sp. dwarfing and proliferation Svobodova (1963)* Fagus sp. stem pitting Parker (1974) Fagus sp. leaf chlorosis, ring Er line patterns Schmelzer et al. (1966) Fraxinus sp. dwarfing Et proliferation Kuprevicz (1947)* Ginkgo sp. leaf interveinal yellowing and patterns Smolak (1964) Gleditsia sp. leaf yellow ring Et line patterns Atanasoff (1935) Mahonia sp. leaf vein banding Kochman Er Styra (1957)* Populus x branch or stem (1) pitting 8 grooving Mackay (Bryant Et May euramericana (cv Gelrica Et Eugeniei) (Forestry) Ltd., Willington (2) swelling (cv Rap Er TT32) Beds. unpublished d'ata) Quercus spp. (1) leaf mosaic or flecking Schmelzer et al. (1966) (2) stunting mottling Er bud precosity Gregory and Seliskar (1970) Rhododendron sp. swollen internodes Brooks (R.H.S. Wisley, Surrey unpublished data) Rhododendron sp. leaf distortion and mottle Pape (1931) Robinia sp. leaf deformation Hartel Et Thaler (1959)* Sarcoccocca sp. leaf vein yellowing Bestangno (1960)* Ulmus sp. leaf necrotic collapse Svobodova (1963)* Ulmus sp. trunk "witchesbrooms" Atanasoff (1973)

*Authorities marked with an asterisk are cited in Schmelzer (1968)

References Pflanzliche Virologie (Edited by Klinkowski. M). 2 (2). 232-203. Atanasoff, D. (1935). Old and new virus diseases of trees and Berlin, Akademie-Verlag. shrubs. Phytopath. Z. 8, 197-223. Schmelzer, K., Schmidt, H.E. und Schmidt, H.B. (1966). Virus Atanasoff, D. (1973). Stammhexenbesen bei Ulmen und ander Krankheiten und virus ver dachtige Erscheinungen an Forstge- en Baumen. Archiv. fur Phytopathologie und Pflanzenschutz 9, holzen. Arch. Forstw. 15, 107-120. 241-243. Sibilia, C. (1947). Le virosi nelle specie forestali. Ital for. mont. Deighton, F.C. and Tinsley, T.W. (1958). Notes on some plant 2, 67-74. virus diseases in Ghana and Sierra Leone. J. W. Afr. Sci. Ass. 4, Smolak, J. (1949). Virove choroby a listy. Ochr. Rost. 22, 173- 4-8. 203. Gregory, G.F. and Seliskar, C.E. (1970). A virus-like disorder of Smolak, J. (1964). Virus diseases of Ginkgo biloba? Preslia 36, Overcup Oak. Pl. Dis. Reptr 54. 844-846. 1-7. Kuhnholtz-Lordat, M. (1944). Le deperissement des chataigner Wiehe. P.O. (1948). The plant diseases and fungi recorded from aies cevenoles. Ann. Ec. Agric. Montpellier 26. 32-34. Mauritius. Mycol. Pap. Commonw. mycol. Inst. 24, 39 pp. Novak, J.B. (1966). Transmission and dissemination of virus diseases on some woody plants. Sb. vys. Sk. zemed. Praze, 1966, 471-484. Parker, E.J. (1974). Beech bark disease. Forest Rec., Lond. no. 96. Pape. H. (1931). Mosaikkrankheit bei Rhododendron. Garten- welt Berl. 35, 621. Ploaie, P.G. and Macovei, A. (1968). New plant virosis recorded in Roumania. Revue roum. Biol. (Ser. Bot.) 13, 269-274. (For. Abstr. 30, 4218). Schmelzer, K. (1968). Zier-, Forst- und Wildgeholze. In :

73 Acknowledgements

Grateful acknowledgement for encouragement, suggestions and comments is due to Prof. F. T. Last, Dr. T. W. Tinsley, Mr. P. Somerset Fry, and Mr. P. Marriage who read the full text, and to Drs. M. L. Edwards, M. Hollings, A. T. Jones, F. A. van der Meer, J. B. Novak and J. B. Sweet, who offered constructive criticism of certain sections. I am also indebted to Miss M. Gomblich for translating German papers, and to many colleagues who sent me written notice of their unpublished observations. The names of those who lent photographic prints are given under each mono : chrome illustration, most were printed by C. Hatton, Unit of Invertebrate Virology, Oxford. The Colour photographic prints were lent by the following : Plates 2a, 2b, Plates 16, 17, 30, 32, 35, 53, 58a 58b Plates 18, 19— J. G. Berbee and A. R. Gotlieb. Plate 25—J. L. Dale. Plate 42—C. R. Hibben. Plate 45a—A. Quacquarelli.

Finally, I want to thank Mrs. Joyce Bald, Miss Sally McDonald and Miss Melina Rowland for cheerfully undertaking most of the arduous task of typing and re- typing the text.

J. I. Cooper Oxford, 1978

Abbreviations

AMV arabis mosaic virus CLRV cherry leaf roll virus CLSV apple Chlorotic leaf spot virus CMV cucumber mosaic virus LMV lucerne (alfalfa) mosaic virus MLO myco plasma-like organism RLO — rickettsia-like organism SLRV strawberry latent ringspot virus TBRV tomato black ring virus TMV — tobacco mosaic virus TNV tobacco necrosis virus TobRSV — tobacco ringspot virus TomRSV — tomato ringspot virus TRV tobacco rattle virus

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