Dutch Elm Disease

12 Key excerpts on "Dutch Elm Disease"

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  Biocontrol Of Plant Diseases

  • K. G. Mukerji, K.L. Garg(Authors)
  • 2020(Publication Date)
  • CRC Press

    (Publisher)

  Currently, Dutch Elm Disease is the most widely known plant disease in the western world. It also is the most intensively studied tree disease and a prime example of a disease for which virtually every approach for control has been pursued. Recent results on control warrant this review.

  The story of Dutch Elm Disease thus represents a model for vascular diseases, as the life cycle of the pathogen is known in ever increasing detail, and transmittance of the disease is by vectors or root contact. Also, artificial infection of the host is simple, and trees having various degrees of resistance are known.

  II. HISTORY OF Dutch Elm Disease

  In 1919 in the southern Netherlands, elms were discovered showing symptoms of a yet unknown disease: a sudden wilting and dying of the leaves and branches. Trees, which in early summer appeared normal, in full leaf, sometimes withered, lost all their leaves and died within a matter of weeks. In others, the leaves on a few branches in the crown turned yellow and fell, and by late summer these symptoms spread over the crown with no distinct boundaries. On shoots overtaken by the disease during growth, the end leaves on the withered and stunted tips often remained after the fully grown leaves had fallen off, thereby producing a characteristic “shepherd’s crook” effect. In addition, diseased branches, when cut, always revealed a dark discoloration of the wood, at any rate, in the most recent growth ring. The disease was described by Spierenburg.

  83 ,84

  At the Willie Commelin Scholten Phytopathological Laboratory, Schwarz79 isolated one fungus from discolored current-year sapwood that never grew from healthy elm wood. On the basis of the coremia formed she described the fungus as Graphium ulmi, and she concluded that this was the pathogen causing the disease in the elms. However, others held different opinions, from bacteria to climatical or soil factors, or even mustard gas that was used in the great war.

  21 ,39 ,40

  Wollenweber100 and Westerdijk96 proved that G. ulmi was indeed the causal organism.

  Wollenweber101 found G. ulmi in diseased elms in galleries of the larger elm bark beetle, Scolytus scolytus; and Betrem6 isolated the fungus from this beetle. The following papers of Roepke,71 Fransen,

  28 , 29 , 30

  and Fransen and Buisman31 made it clear that the elm bark beetles S. scolytus and S. multistriatus were vectors of G. ulmi

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  dsRNA Genetic Elements

  Concepts and Applications in Agriculture, Forestry, and Medicine

  • Stellos M. Tavantzis(Author)
  • 2001(Publication Date)
  • CRC Press

    (Publisher)

  181 7.3 Viruses as Potential Biological Control Agents for Dutch Elm Disease ......................................................................................................... 182 References .............................................................................................................. 184 7.1 INTRODUCTION The biology of the Dutch Elm Disease fungi will first be described to provide a basis for understanding the role of their viruses in the epidemiology of the disease and the potential of the viruses for development as biological control agents. 7.1.1 T HE D UTCH E LM D ISEASE C YCLES Dutch Elm Disease (DED) is caused by the ascomycete fungi, Ophiostoma (formerly Ceratocystis ) ulmi and O. novo-ulmi . 1–9 Both species are heterothallic (obligatorily outcrossing) with two mating types, designated A and B. DED is transmitted by scolytid elm bark beetles of which Scolytus scolytus and S. multistriatus are the 7 166 dsRNA Genetic Elements: Concepts and Applications most important. S. scolytus is so far confined to Europe and central Asia, but S. multistriatus now occurs in both Europe and North America. The annual disease cycle is characterized by saprotrophic and pathogenic phases. At the start of the saprotrophic phase in summer and autumn, bark of diseased trees is colonized by beetles carrying spores of O. ulmi or O. novo-ulmi . Breeding galleries are carved out, around which the fungi multiply by mycelial growth between autumn and spring with a distinct sequence of sporulation, involving formation of conidia, synnemata, and ascospores. 10–11 In the spring, newly hatched beetles, carrying fungal spores, emerge and fly to healthy elm trees where they cut feeding grooves in the crotches of twigs. In so doing, the beetles contaminate feeding grooves with the fungus which, after a brief mycelial phase, enters the xylem where it multiplies as yeast-like cells (blastospores).

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  Field and Laboratory Guide to Tree Pathology

  • Robert Blanchard(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  (Photographs courtesy of Shade Tree Laboratories, University of Massachusetts, Amherst.) Disease: Dutch Elm Disease 85 Fig. 10.7 Coremia of the Graphium state of Ceratocystis ulmi. (Photograph courtesy Botany and Plant Pathology Dept., University of New Hampshire, Durham.) can then transmit the pathogen to healthy trees. The sexual state of the fun-gus, a long-necked perithecium, is rare in nature. However, it may play a role in the development of new strains of the pathogen. In laboratory culture (Fig. 10.8) a second conidial state, Cephalosporium spp., can be easily isolated from infected elm tissue (see Exercise IV). When elm trees of the same species grow close to each other, root grafts often form and the pathogen can move through the root system of an infected tree to invade an adjacent healthy one. 86 10. Wilt Diseases Fig. 10.8 Young culture of Ceratocystis ulmi grown from a section of discolored wood placed on a nutrient medium. (Photograph courtesy of Shade Tree Laboratories, University of Massachusetts, Amherst.) Control: Sanitation: Remove all dead and dying elms as soon as they are detected. Remove all infected branches during the initial stage of the disease by pruning at least 10 feet (3 meters) behind any vascular discoloration. Cut root grafts adjacent to infected trees either by trenching to 3 feet (1 meter) or with a soil fumigant to kill a thin band of roots. Vector control: Apply dormant insecticide spray during early spring. Pheromones have been synthesized and show promise for reducing beetle populations by capturing them in pheromone traps. Prophylaxis and therapy: Numerous methods for tree injection of mate-rials inhibitory to the pathogen, to protect healthy trees or to save infected ones, are currently under investigation. The effectiveness of injection as a treatment for Dutch Elm Disease is controversial and there is concern over repeated multiple wounding from injections. Disease: Oak Wilt 87 Selected References Banfield, W.

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  Diseases of Shade Trees

  • Terry A. Tattar(Author)
  • 2013(Publication Date)
  • Academic Press

    (Publisher)

  Small twigs less than 1 inch (2.5 cm) in diameter 12. Wilt Diseases Fig. 12.1 Dutch Elm Disease in American elm. Note defoliation and wilting on the left half of the tree and normal appearance on most of the right half. Inset close-up of wilted and curled leaves. (Photo courtesy of Shade Tree Laboratories, University of Massachusetts, Amherst.) Fig. 12.2 Discoloration in outer xylem of an elm twig taken from a tree with Dutch Elm Disease. (Photo courtesy of Shade Tree Laboratories, University of Massachusetts, Amherst.) Wilt Diseases of Trees 171 should be removed from affected branches. If the outer wood is shaved with a knife a band or scattered lines of discoloration are revealed in infected twigs. Discoloration can also be found in larger branches, the trunk, and sometimes the roots of severely infected trees. In dead trees or trees infected more than one season, egg galleries of bark beetles can be found beneath recently killed bark (Fig. 12.3). Disease Cycle Dutch Elm Disease is caused by the fungus Ceratocystis ulmi (Fig. 12.4). This fungus overwinters in infected and recently killed trees, in stumps, and in recently cut brush and logs. The fungus is carried from infected wood to healthy trees by elm bark beetles. Two species of elm bark beetles are important vectors of this pathogen, the European and the native elm bark beetle. Both these insects lay their eggs under the bark primarily in stressed, dead, or dying elms. In the late fall the eggs hatch and produce larvae which tunnel beneath the bark. In early spring the larvae form the pupal resting stage and emerge as adults in mid to late spring. In infected trees the fungus produces balls of sticky spores in the beetle galleries (Fig. 12.5). The bodies of the adult elm bark beetles are contaminated with these spores when they emerge. The Fig. 12.3 Egg galleries of the European elm bark beetle beneath the bark of an American elm.

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  Forest Microbiology

  Volume 2: Forest Tree Health

  • Fred O Asiegbu, Andriy Kovalchuk(Authors)
  • 2022(Publication Date)
  • Academic Press

    (Publisher)

  Fig. 23.2 .

  Fig. 23.2 Current distribution of Dutch Elm Disease (DED) pathogen around the world.

  A yeast-like multiplication of the O. ulmi causes cavitation of xylem vessels and wilting of tree shoots (Webber and Brasier, 1984 ). The fungus develops as a saprobe inside dying elms. Spores are attached to the bark beetle bodies, as fungal fruiting bodies emerge from the infected tissues (Rudinsky, 1962 ; Scheffer et al., 2008 ). The female beetles that inhabit the bark introduce new pathogen genotypes that can be passed on to the vector beetles upon their maturation (Santini and Faccoli, 2015 ). As the new generation of beetles emerges, they bear fungal conidia and ascospores on their bodies and complete the disease cycle by feeding on healthy elms upon maturation (Webber and Brasier, 1984 ). Neely and Himelick (1963) have observed another mode of disease spread of DED via root contacts.

  DED is difficult to monitor due to its rapid and effective spread. Insecticides, field soil treatments, systemic fungicides injections, and extensive sanitation through eradicative pruning have all been reported to be utilized against Dutch Elm Disease (Cuthbert, 1973 ; Marsden, 1952 ; Neely and Himelick, 1965 ; Stipes, 1975 ; Lanier, 1987 ). Scientists have recommended the facilitation of one or more of these procedures, however, this must be replicated every year for the disease control. In addition to high cost, increasing public concern about the environmental effects of chemical pesticides has raised discussion of the feasibility of control. Therefore, it is important to establish more economical and environmentally friendly methods of control. Apart from chemical treatment and mechanical removal of diseased trees, some researchers have suggested alternative ways of incorporating antagonistic microorganisms into elms as a means for disease prevention or suppression (Martín et al., 2010 ; Scheffer et al., 2008 ). Hence, different fungi species have been tested as biocontrol agents against DED (Martín et al., 2010 ; Webber, 1981 ). Interestingly, Hubbes and Jeng (1981) found that DED-sensitive elms pre-infected with O. ulmi spores developed resistance to a subsequent O. novo-ulmi

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  In Splendid Isolation

  A History of the Willie Commelin Scholten Phytopathology Laboratory, 1894-1992

  • Patricia E. Faasse, Eliane Smits van Waesberghe, Hans Boutellier, Fouzia Outmany(Authors)
  • 2008(Publication Date)
  • Amsterdam University Press

    (Publisher)

  van Lonkhuijzen [a board member of the nhm ] who, by virtue of his function, has had immense practical experience with the manifestation of elm disease, attributes the occurrence of this disease primarily not to the agency of a parasitical fungus, but to drought; it may be noted that Miss Dina Spierenburg also by no means regarded the fungi and bacteria that she cultured from the wood of diseased elm trees as the actual cause of elm disease, but took 32 H.A.A. van der Lek, ‘Afscheiding van giftstoffen door zwammen, welke ziekten der houtvaten veroorzaken’ , Tijdschrift over Plantenziekten , 1922 , pp. 183 -186 . 110 ‘ out in baarn ’ the view from the beginning that the primary role in this disease was played by unfavourable external influences.’ 33 It is true that Spierenburg had stressed the role played by external condi-tions on the genesis and development of elm disease at the annual meeting of the nhm in 1922 . ‘Whether the fungus causes the disease cannot yet be stated with certainty.’ 34 ‘A practician is more inclined to ascribe the primary cause of plant diseases to weather conditions, while someone who works with the microscope as-cribes greater influence to the fungi he encounters’, wrote Westerdijk in a con-ciliatory tone in the daily newspaper the Nieuwe Rotterdamsche Courant . ‘This will always lead to some gnashing of teeth on both sides. … In most cases it has become clear that both the right conditions and the parasite must be present for the disease to occur.’ 35 Still, it remained incontrovertible, and of irrefutable accuracy, she insisted, that elm disease was an infectious disease attributable to a fungus. After 1922 , the incidence of elm disease appeared to be past its peak. The trees looked less diseased, and the number of reports of diseased trees was declining.

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  Fungal Wilt Diseases of Plants

  • Marshal Mace(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  sp. cubense. With indigenous plant species the destructiveness of fungal wilt diseases has been even more ominous. Dutch Elm Disease has now spread from coast to coast in the United States and continues to spread in Canada, destroying untold numbers of both planted and wild elms. Although less spectacular, oak wilt has continued to intensify, espe-cially in the upper Mississippi valley region, and persimmon wilt, caused by Cephalosporium diospyri, has nearly eliminated native stands of American persimmon (Diospyros virginiana) in eastern Ten-nessee. In crop plants, it is of interest that during the period from 1890 to 1920 there were numerous reports of new fungal vascular wilt diseases, especially those caused by Fusarium species. It seems more than coin-cidental that these reports would correspond with the period in which great strides were made in crop improvements through selection and the application of Gregor Mendel's (1900) newly rediscovered prin-ciples of heredity. The narrowing of the genetic base of numerous agronomic and horticultural crops through selection and plant breeding and the intensive monoculture of these crops undoubtedly contributed to the emergence of at least some of the fungal wilt pathogens. In fact, this period may hold the key to the appearance of many of the fungal wilt diseases that have become important limiting factors in crop production. In only a limited number of cases is the origin of a particular fungal wilt pathogen known. For example, the origin in North America of Ceratocystis ulmi, causal agent of Dutch Elm Disease, is quite clear. Both the fungal pathogen and one of the two major insect vectors, the lesser European elm bark beetle, Scolytus multistriatus, were intro-duced from Europe in recent times, the former in the early 1930s (May, 1931) and the latter sometime before 1900 (Whitten, 1967). However, the fungus is not native to Europe and was introduced to that area be-tween 1900-1913, but how and from where is unknown.

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  Mycoplasma Diseases of Trees and Shrubs

  • Karl Maramorosch(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  the relative importance of these two diseases in an extensive study of disease spread in the twin cities of Champaign and Urbana, Illinois, over a 29-year period. Of the original population of 14,103 elms, 21.23% were killed by elm phloem necrosis in 29 years. Dutch Elm Disease killed 78.44% in 22 years. It is interesting to note that where both diseases occur together, the presence of phloem necrosis results in an increase in the incidence of the Dutch Elm Disease. Apparent-ly, the bark beetle vectors of DED colonize and breed in dead or dying elms, including those attacked by phloem necrosis (Campana and Carter, 1955). On the other hand, the leafhop-per vector of phloem necrosis does not colonize dead elms and thus no increase in its incidence can result from DED (Cam-pana, 1958). It can be expected, instead, that the incidence of phloem necrosis will actually be reduced by the removal of elms from the population by DED. Elm phloem necrosis occurs naturally on most American elm species, including American elm, Ulmus americana, L. ; winged elm, U. alata Michx.; cedar elm, U. crassifolia Nutt; Septem-ber elm, U. serotina Sarg; and U. rubra Muhl., red or slippery elm (Swingle, 1942; Sinclair, 1972; Sinclair and Filer, 1974; Sinclair et al., 1976). Naturally infected hybrids of U. rubra and U. pumila were also observed (Braun and Sinclair, 1979). Ulmus thomasii Sarg., cork or rock elm, was susceptible to infection by graft transmission in preliminary inoculation Fig. 11. Urban epiphytotic of elm phloem necro-sis on American elms in midwestern United States. Natural root graft transmission of PN may occur with closely spaced trees. Fig. 12. Phloem necrosis-infec-ted American elm, Ulmus americana L., showing discoloration in the inner bark of small tree. Such bark commonly gives off an odor of wintergreen if confined in the hand for a few moments.

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  Insect-Fungus Interactions

  • Bozzano G Luisa(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  multistriatus are involved (Readio, 1935). The outline of the disease cycle has been known since the 1930s and starts when a new generation of scolytids emerge from elm bark. They carry on their bodies spores of the pathogen, and while seeking out bark for fresh breeding material often feed in the twig crotches of healthy elms. Although this is not an obligatory part of the beetle life-cycle (Fisher, 1937; Choudhury, 1979), it is the means by which O. ulmi infects elms, the wounds made by the beetles (feeding grooves) serving as infection courts for the pathogen (Fig. 3B). External symptoms of wilting and foliage-yellowing then follow, with concurrent development of internal wood discoloration as O. ulmi spreads through the outermost ring of xylem vessels. An infected tree may succumb to the disease within a single season or over several years, but eventually the bark of a dying elm can be colonized by breeding scolytids. As they enter to breed, the beetles may again carry in spores of O. ulmi, with the end result that the fungus colonizes the dying elm bark in association with the developing scolytid broods. This period of bark colonization by insect and fungus generally occurs during the winter, although it can be compressed into a few weeks in a summer generation, and ensures that pathogen and Fig. 3. (A) Larger European elm bark beetle, Scolytus scolytus, vector of Dutch Elm Disease. (Forestry Commission copyright.) (B) Feeding grooves (arrowed) produced by S. scolytus on Ulmus procera. 7. Insect Dissemination of Fungal Pathogens 173 vector are reunited by the time of beetle emergence in the early summer. Put in these terms the basic disease cycle appears simple, but the association between fungus and insect is by no means a straightforward one. An illustration of this is provided during early stages of larval growth, when the developing gallery consists of a central maternal tunnel with outwardly fanning larval galleries.

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  Plant Pathology

  • Stephen Burchett, Sarah Burchett(Authors)
  • 2017(Publication Date)
  • Garland Science

    (Publisher)

  This plant disease caused the deaths of over 1 million people, and compelled a further 2 million to emigrate, mostly to the USA. The second example, Dutch Elm Disease, did not directly affect food supply but did result in a profound change to the rural landscape of the UK. During the 1960s and 1970s, an outbreak of Dutch Elm Disease (caused by Ceratocystis ulmi, a fungal pathogen spread by the bark beetle, Scolytus scolytus) resulted in the widespread loss of English elm (Ulmus procera). It was estimated that around 25 million elm trees were lost. This had a significant impact on the rural landscape, removing a rural icon from many regions of the UK. A similar problem, known as sudden oak death (caused by Phytophthora ramorum), is now facing managers of stately homes, rural estates, popular public gardens, and woodlands. This problem is not restricted to the UK, as P. ramorum has also had an impact on landscapes in the USA and further afield, such as Big Sur in California, where many tanoaks (Lithocarpus densiflorus) have succumbed to the disease. Furthermore, P. ramorum is not restricted to oak species, as the common name of the disease implies, but is affecting a number of other tree genera, such as the larch (Larix species). These well-known examples illustrate how plant pathogens have both direct and indirect effects on human societies. Another excellent historical example is the way that coffee leaf rust resulted in the UK becoming a nation of tea drinkers. Globally, coffee (Coffea arabica) is a highly valuable crop; the global value of green coffee in 2013 was estimated to be US$ 9.8 billion. The major fungal pathogen of coffee is coffee leaf rust (Hemileia vastatrix), which leads to total defoliation of coffee plants in the second year of infection

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  Diseases of Shade Trees, Revised Edition

  • Terry A. Tattar(Author)
  • 2012(Publication Date)
  • Academic Press

    (Publisher)

  Can. For. Serv. Inf. Rep. . 1972; O-X-171:1–11.

  SUGGESTED REFERENCES

  Cannon, W.N., Worley, D.P. Dutch Elm Disease control: Performance and costs. U.S., For. Serv., Res. Pap. . 1976; NE-345:1–7.

  Fowler, M.E. Oak wilt. U.S., For. Serv., For. Pest Leafl. . 1958; 29:1–7.

  Gregory, G.F., Jones, T.W. An improved apparatus for pressure-injecting fluid into trees. U.S., For. Serv., Res. Note NE . 1975; NE-214:1–6.

  Hanisch, M.A., Brown, H.D., Brown, E.A. Dutch Elm Disease management guide. USDA Forest Serv., Bull. . 1983; 1:1–23.

  Himelick, E.B. Verticillium wilt. Proc. Int. Shade Tree Conf. . 1968; 44:256–262.

  Himelick, E.B. Tree and shrub hosts of Verticillium albo-atrum. Ill. Nat. Hist. Surv., Biol. Notes . 1969; 66:1–8.

  Himelick, E.B. High pressure injection of chemicals into trees. Arborist’s News . 1972; 37:97–103.

  Himelick, E.B., Neely, D. Prevention of root graft transmission of Dutch Elm Disease. Arborist’s News . 1965; 30:9–13.

  Holmes, F.W. The American elm fights back. Horticulture . 1976; 54:72–78.

  Schreiber, L.R., Peacock, J.W. Dutch Elm Disease and its control. U.S., Dep. Agric., Agric. Res. Serv., Bull. . 1974; 193:1–15.

  Sinclair, W.A., Campana, R.J. Dutch Elm Disease—Perspective after 60 years. Northeast Regional Research Publication, Cornell University, 1978; 52. [Search Vol. 8, No.5].

  Van Alfen, N.K., Walton, G.S. An evaluation of the Lowden formulation containing nystatin for Dutch Elm Disease control. Plant Dis. Rep. . 1974; 58:924–926.

  Wilson, C.L. The long battle against Dutch Elm Disease. J. Arbori. . 1975; 1:107–112.

  Wilson, C.L. Recent advances and setbacks in Dutch Elm Disease research. J. Arbori. . 1976; 2:136–139.

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  Wound Diseases—Discoloration and Decay in Living Trees

  Publisher Summary

  A wound is a break in the bark where the wood underneath is exposed. Wound is the first step in a complex series of events that leads to the discoloration and decay of wood in living trees. The type and severity of the wound and the wound response of the host are the indicators of the potential amount of discoloration and decay that will occur in a tree. This chapter discusses the various types of wounds that occur in shade trees and describes the means to treat wounds to minimize discoloration and decay. The examination of wounds as the predictors of defect has proven to be an accurate and easy procedure. Shade trees are constantly being wounded because of their proximity to the activities of people. Some common sources of wounding are automobiles, bicycles, birds, cats, dogs, fire, lawnmowers, people, and snowplows. The chapter discusses the microbial successions after wounding; many species of fungi and bacteria grow on wounded tissues.

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  Trees & Forests, A Colour Guide

  Biology, Pathology, Propagation, Silviculture, Surgery, Biomes, Ecology, and Conservation

  • Bryan G. Bowes(Author)
  • 2010(Publication Date)
  • CRC Press

    (Publisher)

  As the fungal material builds up, pressure is exerted on the dead bark, which cracks, allowing entry by sap beetles. Management Several management protocols have been instigated in the central states of the USA, where oak wilt is most 173 M ICROBIAL AND V IRAL P ATHOGENS , AND P LANT P ARASITES OF P LANTATION AND F OREST T REES serious. As the disease attacks host trees in forests, woodlands, parks, and gardens, there is an education policy that aims to inform the public of the symptoms and infection biology of the disease, plus likely methods of management. Methods adopted include surveying for the disease, management to reduce wounding or to treat wounds with paint within minutes of damage occurring, root graft cutting to prevent physical transmission, and injection of the fungicide propiconazole (see management of Dutch Elm Disease). VIRUS DISEASES Virus diseases of plants are extremely important worldwide, causing huge economic losses. Most plants become infected by viruses, although some may have little apparent effect on plant growth. Some examples in trees ( 428–431 ) include poplar mosaic carlavirus, apple mosaic ilaravirus, and cherry leaf roll nepovirus, while many other virus-like infections have been noted. Importance Poplar mosaic carlavirus can cause 30% loss in increment in certain Populus (poplar) cultivars. Very little information is available in relation to losses to virus infections in other trees, with most coming from work on fruit trees. Viruses are generally not host specific, infecting a wide range of unrelated hosts. Forest trees, therefore, may become reservoirs of infection for other crops. For example, tobacco ringspot virus was found in Cupressus arizonica (Arizona cypress), tobacco necrosis virus has been isolated from Larix decidua (European larch), and strawberry latent ringspot was found in species of Aesculus .

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