The following information was compiled for the CABI Crop Protection Compendium, CABI Publishing. Updated 2001 by C.J. Baker and T. C. Harrington and by T. Harrington in 2004. This information was gathered in part through funding by the National Science Foundation (DEB-9870675 and DEB-0128104).

Taxonomy and Nomenclature

PREFERRED SCIENTIFIC NAME: Ceratocystis fimbriata Ellis and Halsted

CLASS: Pyrenomycetes

ORDER: Microascales

FAMILY: Ceratocystiaceae

NON-PREFERRED SCIENTIFIC NAMES	TAXONOMIC AUTHORITY
Ceratostomella fimbriata	(Ellis and Halsted) Elliott
Endoconidiophora fimbriata	(Ellis and Halsted) Davidson
Ophiostoma fimbriatum	(Ellis and Halsted) Nannf.
Sphaeronema fimbriata	(Ellis and Halsted) Sacc.
Rostrella coffea	Zimmerman
Ceratocystis fimbriata f. platani	(Ellis and Halsted) Walter

Common names of diseases

English : Ceratocystis blight , blight of mango , wilt disease of cocoa , cacao wilt , mouldy rot of rubber , black rot of sweet potato , canker of coffee , Ceratostomella wilt, mango blight , black cane rot of Syngonium , black canker of aspen , black rot of sunn hemp , black rot of taro , canker stain of plane tree , Ceratocystis canker , Ceratocystis wilt , mallet canker , mango wilt , sweet potato black rot , target canker of aspen ,
Spanish : llaga macana de cacao , mal de choroni de cacao , mal del machete de cacao , muerte subita de citrus , secamiento de los citricos , mal de machete , necrosis del tronco del cacao , marchitez de chupones: cacao ,
French : chancre colore du platane , tache chancreuse , fletrissement du cacaoyer , pourriture des saignees de l'hevea ,
Brazil : seca da mangueira ,

Notes on taxonomy and nomenclature
Ceratocystis fimbriata, the type species of the genus, was originally described on Ipomoea batatus (sweet potato) in 1890 (Halsted, 1890). Saccardo (1892) transferred the species to Sphaeronaema, Elliott (1923) transferred it to Ceratostomella, Melin and Nannfeldt (1934) transferred it to Ophiostoma, and Davidson (1935) transferred it to Endoconidiophora. Placement in Ceratocystis has been accepted since 1950 (Bakshi, 1950).

A fungus attacking Coffea in Indonesia was described as Rostrella coffea (Zimmerman, 1900), and this species was later synonymized with C. fimbriata (Pontis, 1951), although no careful comparisons have been made. Walter et al. (1952) designated the pathogen attacking Platanus as a separate form, C. fimbriata f. platani, based on its purported host specificity. Another form, occurring on Acacia mearnsii and species of Protea in South Africa, is now considered a separate species, C. albofundus (Wingfield et al., 1996); it is likely native to southern Africa (Roux et al., 2000). C. variospora, found on Quercus and described by Davidson (1944), is similar to C. fimbriata (Hunt, 1956). Although Upadhyay (1981) considered C. variospora a synonym of C. fimbriata, it is probably a separate species. It is becoming increasingly apparent that C. fimbriata is a complex of many species, each with a unique host range and geographic distribution.

HOST PLANTS AFFECTED BY C. FIMBRIATA

Theobroma cacao (cacao)

Mangifera indica (mango)

Ipomoea batatas (sweet potato)

Platanus acerifolia (London plane)

Platanus orientalis (Oriental plane)

Platanus occidentalis (American sycamore)

Platanus racemosa (California sycamore)

Coffea spp. (coffee)

Eucalyptus spp.

Citrus spp.

Citrus aurantium (sour orange)

Prunus dulcis (almond)

Prunus armeniaca (apricot)

Crotalaria juncea (sunn hemp)

Hevea brasiliense (rubber)

Gmelina arborea (melina, snapdragon tree)

Pimenta officinalis (pimento)

Punica granatum (pomegranate)

Colocasia esculenta (taro, dasheen, inhame)

Xanthosoma sp. (dasheen, malanga, cocoyam, yautia)

Syngonium spp.

Ficus carica (fig)

Cajanus cajan (pigeon pea)

Populus spp.

Carya cordiformis (bitternut hickory)

Carya ovata (shagbark hickory)

Spathodea campanulata (African tulip tree)

Cassia renigera

Acacia decurrens

Acacia mearnsii

Alocasia sp. (giant taro)

Annona

Erythrina sp.

Manihot esculenta (cassava)

Herrania sp.

Notes on host range
A wide variety of annual and perennial plants are attacked by C. fimbriata. There are several apparently host-specialized strains that are sometimes called 'types', 'races' or 'forms' (Wellman, 1972; Harrington, 2000; Baker et al., 2003), and many of these may prove to be distinct species. Webster and Butler (1967a) considered such types as members of a single, highly variable species. However, isolates from some hosts and some regions are genetically unique (Santini and Capretti, 2000; Barnes et al., 2001; Johnson et al., 2002; Baker et al., 2003; Marin et al., 2003). Harrington (2000) proposed that the cryptic species within the C. fimbriata complex fall into three broad geographic clades, the North American, the Latin American and the Asian clades. Both rDNA and allozyme analyses support these three major clades (Harrington 2000; Johnson et al., 2002; Baker et al., 2003).

Cross-inoculation studies have established the host-specificity of some of these types. For example, isolates from Mangifera (Ribeiro and Coral, 1968), Ipomoea, Platanus, Gmelina, Coffea, Xanthosoma, Eucalyptus (Baker et al., 2003), Crotalaria, Cajanus and Acacia (Coral et al., 1984) did not infect Theobroma. Isolates from Ipomoea and Colocasia were host-specific when inoculated to these two hosts (Mizukami, 1951), as were isolates from Hevea and Ipomoea (Olson and Martin, 1949), and Coffea and Ipomoea (Pontis, 1951). Isolates from Coffea, Prunus, Theobroma, Quercus and Colocasia failed to infect Ipomoea (Kojima and Uritani, 1976). Isolates from Platanus, Prunus (almond and apricot), Mangifera, Xanthosoma, Gmelina, Eucalyptus and Theobroma were not pathogenic to Ipomoea, and isolates from Ipomoea, Prunus (almond and apricot), Platanus, Coffea, Mangifera, Xanthosoma, Gmelina, Eucalyptus and Theobroma were not pathogenic to Platanus (Crone, 1963; Baker et al., 2003). Costa Rican isolates from Theobroma, Coffea and Xanthosoma were specialized to their respective hosts (Baker et al., 2003). Among Brazilian isolates from various hosts, only a Gmelina isolate could infect Gmelina (Baker et al., 2003). A Syngonium isolate from Australia infected various cultivars of Syngonium, other Araceae and Crotolaria, but not Platanus, Prunus spp., or Ipomoea (Vogelzang and Scott, 1990). Each host-specific type of C. fimbriata appears to have a distinct geographic distribution, although the total number of types and the geographic and host boundaries of each of them have not been fully determined.

Several recorded host plants for C. fimbriata are not included in the listing because they have not been confirmed. Some of these are probably erroneous reports, including the reports of C. fimbriata on soyabean (Glycine max), tobacco (Nicotiana species), potato (Solanum tuberosum), chestnut (Castanea sativa), cucumber (Cucumis sativa), kidney bean (Phaseolus vulgaris), coconut (Cocos nucifera), pineapple (Ananas comosus) and yam (Dioscorea species). There is also considerable confusion over the scientific and common names of edible members of the Araceae (Xanthosoma, Colocasia and Alocasia for example), and it is not always clear which of these genera are referred to in the various reports.

Laboratory experiments have demonstrated C. fimbriata infection of Caladium, Dieffenbachia (Vogelzang and Scott, 1990) and several wild Ipomoea species (Clark and Watson, 1983) that have not been recorded as hosts in nature.

Geographical Distribution

COUNTRY/REGION	HOSTS AFFECTED	REFERENCES
ASIA
CHINA	Ipomoea, Punica, Colocasia	Sy, 1956, BPI specimens
Fujian	Ipomoea	Hu et al., 1999
Yunnan	Punica	Huang et al., 2003
INDIA	Populus, Hevea	Kaushik and Toky, 1992; Ramakrishnan and Radhakrishna, 1963
Karnataka	Punica	Somasekhara, 1999
Maharashtra	Punica	Somasekhara and Wali, 2000
INDONESIA	Hevea	Wright, 1925
Java	Hevea, Coffea	Leefmans, 1934; South and Sharples, 1925; Zimmermann, 1900
Kalimantan	Hevea	Tayler and Stephens, 1929
Sumatra	Hevea	Tayler and Stephens, 1929
JAPAN	Ipomoea, Colocasia	Asuyama, 1938; Okamoto, 1940; Shimizu, 1939
Kyushu	Ficus, Ipomoea	Kajitani and Kudo, 1993; Kato et al., 1982;
MALAYSIA	Hevea	Beeley, 1929; South and Sharples, 1925
MYANMAR (BURMA)	Hevea	Turner and Myint, 1980
TAIWAN	Crotalaria	Lee and Kuo, 1997
AFRICA
CONGO	Eucalyptus	Roux et al., 2000
COTE D'IVOIRE	Crotalaria	Davet, 1962
KENYA	Ipomoea	Kihurani et al., 2000
UGANDA	Eucalyptus	Roux et al., 2001
SOUTH AFRICA	Acacia	Roux et al., 2000
NORTH AND CENTRAL AMERICA
CANADA
British Columbia	Populus	Lowe, 1969, Hinds, 1985
Manitoba	Populus	Zalasky, 1965
Quebec	Populus	Vujanovic et al., 1999
Saskatchewan	Populus	Zalasky, 1965
Yukon Territory	Populus	Hinds, 1985
COSTA RICA	Theobroma, Herrania, Coffea	Baker et al., 2003; Echandi and Segall, 1956; Martin, 1949; Siller, 1958
CUBA	Spathodea, Colocasia, Citrus	Isla and Ravelo 1989; Rodriguez and Alfonso 1978; Triana and Diaz, 1989;
DOMINICAN REPUBLIC	Theobroma	Schieber, 1969
GUATEMALA	Theobroma, Coffea, Hevea	Schieber and Sosa, 1960; Szkolnik, 1951; Tejada, 1983
HAITI	Ipomoea	Barker, 1926
JAMAICA	Pimenta	Leather, 1966
MEXICO	Hevea, Erythrina	Martin, 1947; BPI specimens 596218, 595433
ST VINCENT & GRENADINES	Ipomoea	BPI specimen 596219
TRINIDAD & TOBAGO	Ipomoea, Theobroma	Baker, 1936; Baker and Dale, 1951; Briant, 1932; Iton, 1959; Leach, 1946
UNITED STATES
Alaska	Populus	Hinds and Laurent, 1978
Arkansas	Platanus	McCracken and Burkhardt, 1977
Arizona	Populus	Hinds, 1972
California	Syngonium, Platanus, Prunus	Davis, 1953; DeVay et al. 1968; Perry and McCain, 1988; Teviotdale and Harper 1991
Colorado	Populus	Hinds, 1972
Delaware	Platanus	Mook, 1940; Walter, 1946
District of Columbia	Platanus	Walter et al., 1952
Florida	Syngonium, Alocasia, Colocasia	Alfieri et al., 1994
Hawaii	Syngonium, Colocasia	Uchida and Aragaki, 1979
Idahao	Populus	Hinds, 1985
Kentucky	Platanus	Mook, 1940
Louisiana	Ipomoea	Baker et al., 2003; Webster and Butler, 1967
Maryland	Platanus	Dodge, 1940
Massachusetts	Ipomoea	BPI specimen 595868
Minnesota	Populus	Hinds and Anderson, 1970; Wood and French, 1962
Mississippi	Platanus	Walter, 1946
Montana	Populus	Hinds, 1985
Nevada	Populus	Hinds, 1985
New Jersey	Platanus	Dodge, 1940; Walter, 1946
New Mexico	Populus	Hinds, 1972
New York	Platanus	Walter, 1946
North Carolina	Platanus, Ipomoea	Baker et al., 2003; Walter, 1946
North Dakota	Populus	Hinds, 1985
Oregon	Populus	Hinds, 1985
Pennsylvania	Platanus	Dodge, 1940; Jackson and Sleeth, 1935; Walter, 1946; Webster and Butler, 1967
Rhode Island	Ipomoea	BPI specimen 595867
Tennessee	Platanus	Mook, 1940; Walter, 1946
Utah	Populus	Hinds, 1972
Virginia	Platanus	Walter, 1946; Webster and Butler, 1967
West Virginia	Platanus	Walter, 1946
Wyoming	Populus	HInds, 1972
SOUTH AMERICA
BRAZIL
Bahia	Theobroma, Hevea, Eucalyptus	Baker et al., 2003; Bezerra, 1997; Ferreira et al., 1999; Laia et al., 1999; Pereira and Santos, 1986
Distrito Federal	Crotolaria	Melo-Filho et al., 2002
Minas Gerais	Crotolaria	Chardon et al., 1940; Muller, 1937
Pará	Hevea, Gmelina, Acacia	Albuquerque et al., 1972; Deslandes, 1944; Muchovej et al., 1978
Pernambuco	Crotalaria, Mangifera, Coffea	Batista, 1947, 1960; Upadhyay, 1981
Rio de Janeiro	Mangifera, Annona, Daucus	Cavalho and Carmo, 2003; Baker et al., 2003
Rio Grande do Sul	Acacia	Santo and Ferreira, 2003
Rondônia	Theobroma	Bastos and Evans, 1978
São Paulo	Cassia, Crotolaria, Ficus, Hevea, Mangifera, Acacia	Arruda, 1940; Galli, 1958; Oliveira, 1966; Ribeiro et al., 1987; Ribeiro et al., 1988; Silveira et al. 1985; Valarini and Tokeshi, 1980
COLOMBIA	Theobroma, Coffea, Citrus	Arbelaez, 1957; Borja et al., 1995; Garces, 1944; Marin et al., 2003; Mourichon, 1994; Pontis, 1951
ECUADOR	Theobroma	Chalmers, 1969; Desrosiers, 1957; Desrosiers and Diaz, 1956; Rorer, 1918
GUYANA	Theobroma	Bisessar, 1965
PERU	Theobroma, Ipomoea	Krug and Quartey-Papafio, 1964; Rada, 1939; Soberanis et al., 1999
SURINAME	Coffea	Baker et al., 2003
URAGUAY	Eucalyptus	Barnes et al., 2003
VENEZUELA	Coffea, Theobroma	Malaguti, 1952a, 1952b; Pontis, 1951; Reyes, 1988
EUROPE
AZORES	Ipomoea	Bensaude, 1927
FRANCE	Platanus	Ferrari and Pechenot, 1979, 1974, 1976; Grosclaude et al., 1991; Vigouroux, 1986
ITALY	Platanus	Pancohesi, 1981, 1999
POLAND	Populus	Gremmen and deKam, 1976; Przybyl, 1980, 1986
SWITZERLAND	Platanus	Matasci and Gessler1997
OCEANIA
AUSTRALIA
New South Wales	Syngonium	Walker et al., 1988
Queensland	Syngonium	Walker et al., 1988
Victoria	Syngonium	Walker et al., 1988
FIJI	Xanthosoma	Firman, 1972; Graham, 1965; Walker et al., 1988
NEW ZEALAND	Ipomoea	Baker et al., 2003; Slade, 1960
PAPUA NEW GUINEA	Ipomoea, Hevea	Baker et al., 2003; Mann, 1953
WESTERN SAMOA	Colocasia	Walker et al., 1988

Geographical distribution--further information

In addition to the published reports, the following specimens are held in the US National Fungus Collections: Mexico (BPI 596218 and 595433), St Vincent and Grenadines (BPI 596219), Massachusetts and Rhode Island, USA (BPI 595868 and 595867, respectively); and there is an accession from Suriname in the American Type Culture Collection (ATTC 14503). Confirmed isolates of C. fimbriata have also been collected from Iowa (on Carya cordiformis), Missouri (on Platanus occidentalis) and Wisconsin, USA (on C. cordiformis) (TC Harrington, Iowa State University, USA, unpublished data).

Several older reports of C. fimbriata (cited in CMI, 1983) may be erroneous but have been included in the listed distribution. The fungus has been reported as a saprobe on Hevea in Uganda (Snowden, 1926), and two reports have suggested it as a pathogen on Hevea in the Congo Democratic Republic (Ringoet, 1923; Anon., 1948). Unverified voucher specimens from Fagus and Larix in the UK are cited in CMI (1983), but Larix is a very unlikely host, and there are no confirmed reports of the fungus from the UK. The report of the fungus on Theobroma in the Philippines (Eloja and Gandia, 1963) was only a tentative identification.
Several unnamed forms of C. fimbriata appear to be indigenous to North and South America or Asia but have been introduced elsewhere. Different hosts are attacked in different regions, and even in regions where the fungus is common, not all potential hosts are attacked. For example, mango wilt is known only in Brazil, although Mangifera is grown in other areas where C. fimbriata is common on other plants. The Theobroma form is restricted to Central America and northern and eastern South America, while Coffea forms apparently occur only in Central America and northern South America and, perhaps, a few locations in South-East Asia (Zimmerman, 1900).

Because of the numerous cryptic species in the C. fimbriata complex and the history human-mediated movement of host-specialized strains around the world (Baker et al., 2003), it is difficult to know which of the reports of C. fimbriata in specific countries are of native populations of C. fimbriata or of exotic populations. Thus, many of the above reports have a question mark in the column designating exotic or native. For some of the cases where there is clear evidence that the pathogen was introduced, such as on the ornamental cultivars of Syngonium (Walker et al., 1988), it appears that the fungus has been restricted to only cultivated plants in nurseries or greenhouses. Otherwise, the introduced strains are considered to be invasive populations.

HISTORY OF INTRODUCTION / SPREAD

The Populus form is most abundant in North America, but it has also appeared in Poland and perhaps India, most likely from recent introductions. Cuttings of various Populus species and hybrids were brought into Poland from North America in the 1970s, and C. fimbriata may have been introduced to Poland in these cuttings. Cuttings of P. balsamifera have been shown to harbour the fungus in Quebec nurseries (Vujanovic et al., 1999). The disease was severe in experimental plantings in Poland (Gremmen & de Kam, 1977; Przybyl, 1980, 1986). However, the disease appears to have lessened in importance in recent years and may no longer be present.

The pathogen on Platanus species, f. platani, is believed to be specialized to that genus and was probably introduced to Naples, Italy during World War II on colonized crating material or dunnage from the USA (Panconesi 1981, 1999; Santini and Capretti, 2000; Baker et al. 2003). The pathogen has spread throughout northern Italy (Pancosi 1981, 1999), to Switzerland in 1986 (Matasci and Gessler 1997) and to southern France (Ferrari and Pechenot, 1974, 1976, 1979; Vigouroux, 1986; Grosclaude et al., 1991b).

The cacao form of the pathogen may have been introduced to the state of Bahia in Brazil on infected cuttings of Theobroma cacao (Harrington 2000; Baker et al., 2003). The recent reports of the eucalyptus form of the pathogen in Uganda and the Congo may also be due to introductions on cuttings from Brazil (Roux et al., 2000, 2001; Baker et al., 2003).

The Syngonium form of the pathogen has been dispersed on cuttings of this plant and has been reported in greenhouses in California, Florida, Hawaii and Australia (Davis, 1953; Uchida & Aragaki, 1979; Walker et al., 1988; Alfieri et al., 1994).

The Ipomoea form of the fungus has likely been spread to many locations on storage roots. For example, the report of C. fimbriata in the Azores (Bensaude, 1927) was on experimental plantings of Ipomoea germplasm imported from the Caribbean. The Ipomoea form is apparently native to Latin America and/or the Caribbean (Baker et al., 2003).

Biology and Ecology

Although outcrossing is possible, most isolates are self-fertile due to unidirectional mating type switching (Webster and Butler, 1967a, b; Harrington and McNew, 1997; Witthuhn et al., 2000). Fruiting bodies (perithecia) are produced from the mycelium in culture in about a week. The fungus may be dispersed as fragments of mycelium, conidia, aleurioconidia or ascospores. Aleurioconidia are probably the most common survival units because they are thick-walled and durable, and they probably facilitate survival in soil (Accordi, 1989) and in insect frass (Iton, 1960). The fungus may survive in wood fragments in river water (Grosclaude et al., 1991a) and in the soil (Accordi, 1989) for at least 3 months in the winter. C. fimbriata produces a strong fruity odour that varies with the medium. This has been assumed to be an adaptation for dispersal by insects, which are attracted to diseased plants and can become covered with sticky spores if the fungus is sporulating (see Means of Movement and Dispersal).

Wounds, either natural or from human activities, are important infection courts for all members of the genus Ceratocystis, including C. fimbriata. Inoculum may reach an open wound by being blown in the wind in insect frass (Iton, 1960) or by being carried by insects that visit the wound. Nitidulid beetles that feed on fungi and plant sap may be important vectors (Moller and DeVay, 1968b). Cultivation practices such as pruning may also provide infection courts (Teviotdale and Harper, 1991).

C. fimbriata usually grows best at temperatures from 18 to 28°C and is able to produce ascospores within a week. The fungus probably survives adverse conditions as mycelium within the plant host, or as aleurioconidia in the soil or in plant hosts or debris. The disease in Theobroma has been thought to be most severe during periods of abiotic stresses, particularly drought stress (Spence, 1958), or excessive rain (Malaguti, 1952a). On Ipomoea, attack by C. fimbriata may be enhanced by boron deficiency in the soil (Hu et al., 1999).

Means of movement and dispersal

Natural dispersal

The fungus spreads readily between adjacent Platanus trees via root grafts (Accordi, 1986). It may also infect Platanus trees through wounds in the roots (Vigouroux and Stojadinovic, 1990). Mangifera trees may be infected through the roots from soilborne inoculum (Rossetto and Ribeiro, 1990), and root crops such as Ipomoea are commonly infected through wounds made by insects and rodents (Clark and Moyer, 1988). Ascopores are probably spread naturally by insects and are not likely airborne. Airborne disperal of conidia is also not likely, except in insect frass. Rainsplash dispersal of conidia has not been documented.

Vector Transmission

Many Ceratocystis species produce fruiting bodies and fruity aromas that are believed to be adaptations for dispersal by insects, and C. fimbriata is frequently associated with insects. On Populus (Hinds, 1972b) and Prunus (Moller and DeVay, 1968b), circumstantial evidence suggests that fungal-feeding nitidulid beetles acquire the fungus and visit fresh wounds on susceptible trees. Also, spores of C. fimbriata may be carried upon the bodies of ambrosia beetles (Iton, 1966), and the spores can survive passage through an insect gut (Iton, 1960, 1966; Crone, 1963).

Ambrosia beetles (especially Xyleborus and Hypocryphalus species) are attracted to diseased plants (such as Theobroma, Mangifera and Eucalyptus) and produce large amounts of fine wood shavings (frass) when creating breeding galleries in the trunk and branches (Goitia and Rosales, 2001). These wood shavings and faecal material are pushed outside the tree as the galleries are excavated, and the frass contains spores and fragments of mycelium that may be blown in the wind (Iton, 1960).

Seedborne Spread

No instances of its spread on or with seed have been reported. However, one specimen in the US National Fungus Collections (BPI 596218) of an Erythrina seed pod has many fruiting bodies of C. fimbriata, suggesting that seedborne spread is possible.

Agricultural Practices

Pruning wounds are common entry points for C. fimbriata, and the fungus can be carried on machetes or pruning tools (Walter, 1946, 1952;Teviotdale and Harper, 1991). Platanus street trees may become infected through pruning wounds, and the fungus may be spread on pruning tools or in wound dressings (Walter, 1946). Indeed, proper sanitation and disinfecting tools played a major role in stopping the epidemic on plane trees in urban areas of the eastern USA in the 1920s-1940s (Walter, 1952). Infected wood and sawdust may harbour viable spores for at least 5 years (Grosclaude et al., 1995). On Theobroma, wounds made by harvesting pods, removing stem sprouts or weeding may become infected (Malaguti, 1958), and the fungus also infects pruning wounds and wounds made in harvesting almond fruit (Teviotdale and Harper, 1991).

Because there may be extensive mycelial growth within a plant before symptoms appear, propagative cuttings may be an effective method of dispersal. Healthy-appearing propagative cuttings of Populus were found to be infested with C. fimbriata (Vujanovic et al., 1999). BPI specimen 595645, of propagative material from Costa Rica intercepted in Miami, Florida, USA, contains several Manihot cuttings with abundant perithecia at the nodes. Infected Syngonium cuttings were the apparent means of spread of the Syngonium form of the fungus throughout the greenhouse industry (Walker et al., 1988). The fungus has also been found in both symptomatic and apparently healthy Eucalyptus cuttings in a Brazilian Eucalyptus plantation (CJ Baker, Iowa State University, personal observation). Cuttings, roots and corms are used to propagate many other common hosts of C. fimbriata, including Theobroma, Ipomoea and Colocasia, and this may facilitate long-distance transport of the fungus. The Ipomoea form of the fungus, which is probably native to Latin America, is likely spread on storage roots (Bensaude, 1927; Baker et al., 2003).

Movement in Trade

It is apparent that several host-specialized forms of the fungus have been introduced into many regions. Propagative materials, especially cuttings, are a likely source. Packaging material and dunnage are also likely means of dispersal of the fungus. The Platanus form may have been introduced on packing material to Europe from North America during World War II (Panconesi, 1981, 1999) and has caused substantial damage to ornamental Platanus in southern Europe. This form can survive in Platanus wood taken from diseased trees (Grosclaude et al., 1995), which may be an efficient means of introducing the pathogen to new locations.

Plant parts liable to carry the pest in trade/transport:
- Bark: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible to naked eye.
- Bulbs/tubers/corms/rhizomes: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible.
- Fruits (inc. pods): Spores, hyphae, fruit bodies; borne externally; invisible to naked eye.
- Growing medium accompanying plants: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible.
- Leaves: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible to naked eye.
- Seedlings/micropropagated plants: Spores, hyphae; borne internally; invisible.
- Roots: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible.
- Stems (above ground)/shoots/trunks/branches: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible.
- Wood: Spores, hyphae, fruit bodies; borne internally; borne externally; invisible to naked eye.

Plant parts not known to carry the pest in trade/transport:
- Flowers/inflorescences/cones/calyx.

Transport pathways for long distance movement:
- Containers and packing: Wood used in packaging or dunnage.(Panconesi 1981; Grosclaude et al. 1995)
- Soil, gravel, water, etc.: River water.(Grosclaude et al. 1991a)

Symptoms-Description
C. fimbriata is primarily a xylem pathogen. On trees (Theobroma, Mangifera, Prunus, etc.), infection typically occurs through fresh wounds (Giraldo, 1957; Viégas, 1960; Moller et al., 1969), although root infections are also common (Ribeiro et al., 1986; Rossetto and Ribeiro, 1990; Laia et al., 2000). Mycelium and spores enter wounds and move through the xylem in water-conducting cells and into ray parenchyma cells. The fungus causes dark reddish-brown to purple to deep-brown or black staining in the xylem. This staining may extend several metres from the roots, up the trunk of the tree, and into branches. When affected branches or trunks are cut in cross-section, the staining along the rays gives a distinctive wedge-shaped or starburst-like pattern (Sinclair et al., 1987). On the surface of the trunk or branches, cankers may develop over areas of xylem discoloration, and the cankers may exude gum. Branch and trunk cankers are particularly common on Populus, Prunus, Platanus (Sinclair et al., 1987) and Eucalyptus (Laia et al., 2000), though wilting may also occur in the absence of canker development. Wilted leaves typically become dry and curled rather suddenly but remain attached to the tree for several weeks. On Platanus, individual leaves of affected branches often show interveinal chlorosis and necrosis, perhaps associated with fungal-produced phytotoxins (Ake et al., 1992; Alami et al., 1998; Pazzagli et al., 1999).

Infection of many trees (Theobroma, Mangifera, Punica and others) is often accompanied by secondary attack by various ambrosia beetles (such as Xyleborus and Hypocryphalus species), which bore into the xylem of the diseased trunk and produce copious amounts of frass (wood particles mixed with faeces) (Iton, 1959, 1960; Rossetto and de Medeiros, 1967; Somasekhara, 1999). Frass may cling to the gallery entrance holes in long strands or accumulate on the bark or at the base of the tree. Aleurioconidia may be present in such frass and may be an important source of inoculum. Frass with C. fimbriata may be dispersed by wind or rainsplash.

On rubber trees (Hevea brasiliensis), C. fimbriata attacks the tapping panel, causing a pale-grey mould on the surface of the panel and dark discoloration in the wood under the surface (Martin, 1949; Silveira et al., 1994).

On herbaceous plants (Colocasia, Ipomoea, etc.), C. fimbriata may attack through wounded roots or stems, causing a root rot or seedling rot, or it can travel through the xylem, causing rapid wilting of the plant and extensive dark discoloration of the vascular system. It may also occur as a black, sunken rot on the surface of storage roots or corms of Ipomoea and Araceae such as Colocasia and Xanthosoma, either before or after harvest (Clark and Moyer, 1988).

The fungus has also been reported as a superficial pathogen of harvested cocoa pods, causing soft, brown, rotted lesions (Malaguti, 1958), especially during rainy periods (Siller, 1958). However, a related fungus, C. paradoxa, is more common on rotten cocoa pods, most likely as a secondary invader (Thorold, 1975).

Descriptors: Whole plant: plant dead; dieback; seedling blight; frass visible; wilt. Leaves: necrotic areas; abnormal colours; wilting; yellowed or dead. Stems: discoloration of bark; canker on woody stem; gummosis or resinosis; dieback; mould growth on lesion; internal discoloration; internal feeding; visible frass; wilt; ooze; mycelium present; discoloration. Roots: cortex with lesions. Fruits/pods: lesions: black or brown; lesions: on pods.

Click here to see pictures of symptoms caused by C. fimbriata

Morphology

C. fimbriata grows readily on most agar media. Mycelium is hyaline at first, later turning dark greenish-brown. Within a few days there are usually abundant conidiophores that produce chains of hyaline conidia, sometimes called endoconidia, characteristic of the anamorph genus Chalara. However. Chalara species are anamorphs of discomycetes, and the genus Thielaviopsis is now used for anamorphs of Ceratocystis species (Paulin et al., 2002). Endoconidia are cylindrical and may vary in size from 11 to 16 mm long by 4 to 5 mm wide (all measurements are from Hunt, 1956). Specialized conidiophores give rise to thick-walled, pigmented aleurioconidia (sometimes called chlamydospores), probably a survival spore. Aleurioconidia are typically 9-16 mm long and 6-13 mm wide, borne singly or in short chains. Endoconidia may also darken and become thick walled chlamydospores, thus resembling aleurioconidia. Endoconidia, chlamydospores formed from endoconidia, and aleurioconidia may be produced on and within the substratum.

The teleomorph of the fungus is well adapted to insect dispersal. The fungus has two mating types, and MAT-1 isolates can only produce perithecia when paired with MAT-2 isolates. However, MAT-2 isolates are self-fertile due to uni-directional mating type switching (Harrington and McNew, 1997; Witthun et al., 2000). Most field isolates are MAT-2 and self-fertile, producing many fruiting bodies (ascomata) on the surface of the host or in culture, often within one week. Ascomata are dark brown to black and globose, 130-200 µm diameter with a long, thin neck up to 800 µm long, through which the ascospores are exuded. The opening at the tip of the neck has 8 to 15 ostiolar hyphae ranging in length from 50 to 90 µm. Ascospores are small, hyaline and hat-shaped, 4.5-8 µm long by 2.5-5.5 µm wide, and accumulate in a sticky matrix at the tip of the ascomatal neck, where they appear as a cream to pink ball or coil.

Click here to see pictures of C. fimbriata morphology

Detection and inspection methods

Disease caused by C. fimbriata may be visible on cuttings or other plant material as dark discoloration of the xylem, although symptomless cuttings may still be infected. Ascomata may also occasionally be produced on the surface of stem cuttings, particularly at the nodes. On Ipomoea storage roots and Araceae corms, the fungus may appear as a dry, black rot, usually with perithecia and ascospores. Incubation of colonized plant parts in a humid environment will usually result in ascomata production in only a few days. Unless perithecia are present on the infected plant, a pure culture of the fungus is usually required for reliable identification.

Diagnosis

Pure cultures of C. fimbriata may be obtained by placing chips of discoloured wood from the base of an infected tree or diseased vegetative plant parts in a moist chamber or plating them out on nutrient agar. When the fungus is present, conidia appear in 1-3 days and perithecia in 5-10 days. The presence of fast-growing contaminants, such as Fusarium and Penicillium, may necessitate the use of baits. The Platanus form may be baited from wood, soil or water samples with healthy Platanus twigs stripped of their bark (Grosclaude et al., 1988). All forms of the fungus may be baited from infected plant material by placing a small piece of colonized plant material between two slices of fresh carrot in high humidity for 4-10 days (Moller and DeVay, 1968a). Carrot slices may also be used to bait the fungus from soil (Laia et al., 2000), although carrot is not completely species-specific, allowing the growth of C. moniliformis, Thielaviopsis basicola (Yarwood, 1946), Fusarium spp. and some bacteria. The fungus can also be isolated from the frass of ambrosia beetles (Xyleborus and Hypocryphalus species) in Mangifera, Theobroma and Eucalyptus by using the carrot slice technique.

Molecular or serological diagnostic techniques have not been developed, but there are DNA sequences of ITS-rDNA and other genes unique to C. fimbriata, and these could be developed for diagnosis.

Similarities to other species or conditions

C. fimbriata is usually recognized by its distinctive fruiting bodies, which are somewhat similar to those produced by other species of Ceratocystis and species of Ophiostoma. Ophiostoma species, in contrast to Ceratocystis, do not produce the endoconidial or aleurioconidial states. C. fimbriata has sometimes been confused with Ceratocystis paradoxa, a pathogen of mostly monocotyledonous plants. Both C. paradoxa and C. fimbriata may produce a pod rot of cocoa, although C. fimbriata can be distinguished by its hat-shaped ascospores (Hunt, 1956). Most forms of C.paradoxa are heterothallic, and isolates of this species usually do not produce perithecia unless paired with isolates of opposite mating type.

On Theobroma trees, C. fimbriata may be confused with Ceratocystis moniliformis, which is weakly pathogenic, usually causing only partial wilting or wilting of only a few branches (Barba and Hansen, 1962). In the laboratory, C. moniliformis grows much more quickly on nutrient agar than does C. fimbriata, and when viewed under a compound microscope, the perithecial bases of C. moniliformis have characteristic spine-like ornamentations (Hunt, 1956). Also, C. moniliformis does not produce aleurioconidia. However, C. moniliformis produces hat-shaped ascospores similar to those of C. fimbrata.

Ceratocystis albofundus is morpholocially very similar to C. fimbriata but can be distinguished by its lightly pigmented perithecial bases (Wingfield et al., 1996). Thus far, C. albofundus has only been reported from Africa (Roux et al., 2001).

Infection by many other wilt-type fungi and species of Botryosphaeria may cause xylem discoloration in trees, and it is necessary to isolate C. fimbriata from the discoloured xylem or canker in order to confirm it as the causal agent.

Impact

Economic Impact
Diseases caused by C. fimbriata can be of high local importance, and there is a history of sporadic epidemics. The disease in Theobroma has been of major importance in Costa Rica (Echandi and Segall, 1956), Trinidad and Tobago (Iton, 1959), Ecuador (Desrosiers, 1957), parts of Colombia (Arbelaez, 1957) and Venezuela (Reyes, 1988), and most recently in Bahia, Brazil (Bezerra, 1997). In Theobroma plantations, the fungus has killed as many as 50% of the trees in some locations (Idrobo, 1958). The disease in Coffea is particularly important in Colombia (Pontis, 1951), where citrus is another major economic host (Borja et al., 1995). The disease in Mangifera in São Paulo, Brazil is of major importance (Oliveira, 1966; Ribeiro and Coral, 1968; Rossetto et al., 1969; Yamashiro and Myazaki, 1985; Rossetto and Ribeiro, 1990; Ribeiro et al., 1995;). The fungus has also decimated certain clones of Eucalyptus in plantations in Brazil, and recent reports of the disease in Eucalyptus in the Congo and Uganda have indicated serious levels of mortality (Roux et al., 2000, 2001). Almonds in California, USA, particularly in older orchards, have been seriously affected by the disease, especially after the initial introduction of mechanical shakers, which severely wounded the trees and led to more infections (DeVay et al., 1968). Platanus plantings in Italy, France and Switzerland are also seriously affected, and over 10% of the London plane trees in southern Switzerland have been killed since the early 1980s (Matasci and Gessler, 1997). More than 87% of the plane trees (Platanus acerifolia) were lost during the period 1926-1949 in the community of Gloucester, New Jersey, the earliest recognized epidemic on plane tree in the USA (Walter et al., 1952). By 1952, they had estimated losses in excess of $1,000,000 (in 1952 dollars) in the Northeast. Loss from Ceratocystis wilt on Punica in the Bijapur district of India from 1995 to 1998 was estimated at 7.5% of the crop (Somasekhara, 1999). Although damage from the Ipomoea form is now less severe in southeastern USA than previously (mostly due to the use of resistant varieties and sanitary measures), it remains an important constraint to Ipomoea production in China and Japan (Clark and Moyer, 1988).

Environmental impact

Ceratocystis fimbriata is likely a natural component of many forest ecosystems in the Americas and Asia. On native tree hosts it primarily colonizes wounds but does not move throughout the tree or kill the host. Most mortality of woody hosts appears to be on exotic tree species or native trees in plantations or used as street trees, perhaps because of wounding and movement of the pathogen on tools. The plane tree pathogen, for instance, has been devastating on street trees but rare in natural forests with little human activity (Walter et al., 1952). Even where the fungus has been introduced, the damage is primarily to planted species. Thus, the impact in natural environments has been minimal. However, some plantation species have been abandoned in some regions, such as Gmelina arborea in Pará state in Brazil and Platanus in the southeastern USA.

Social impact
Platanus species, especially P. acerifolia, London plane, is a very common street tree in many regions of the world, especially in the eastern USA and southern Europe. The loss of plane trees in Italy, southern France and Italy due to C. fimbriata has been dramatic, thus seriously reducing the aesthetics of urban areas. Earlier epidemics in urban areas of the eastern USA also had severe impact, though sanitation practices greatly reduced the impact of the disease since the 1940s (Walter et al., 1952).

Control

Host-Plant Resistance
Host-plant resistance has been used successfully with Mangifera (Ribeiro et al., 1984, 1986, 1995; Rossetto et al., 1997), Theobroma (Desrosiers, 1956; Delgado and Echandi, 1965; Gardella et al., 1982; Ocampo et al., 1982; Simmonds, 1994), Ipomoea (Martin, 1954), Coffea (Castillo, 1982), and Crotalaria (Ribeiro et al., 1977). Species and varieties of citrus also vary in susceptibility to Colombian strains of the fungus (Paez-Redondo and Castano-Zapata, 2001).

Cultural Control and Sanitary Measures
Sanitation is also effective for disease control. For example, disinfecting machetes and pruning tools between plants may help control the disease in Platanus (Walter, 1946, 1952) and Prunus (Teviotdale and Harper, 1991). Heat treatment of Ipomoea roots used in propagation has been suggested (Daines et al., 1962).

Chemical Control
Fungicides are used with some success to treat tapping panels of Hevea (Chee, 1970) and in Ipomoea fields (Martin, 1971) or as post-harvest dips of Ipomoea roots (Daines, 1971; Yang et al., 2000). Fungicides injected into the stems of Platanus species may provide some protection (Causin et al., 1995; Minervini et al., 2001). Fungicides are also used to control the disease in Ficus (Hirota et al., 1984).

Phytosanitary risk

Because most forms of the species are easily transmitted in cuttings, unrestricted movement of cuttings or other propagative material is potentially dangerous. It is likely that the fungus has been spread to new countries or regions on cuttings of Populus, Theobroma, Eucalyptus and Syngonium and on storage roots of Ipomoea. Circumstantial evidence points to packing materials as the source of the plane tree pathogen in southern Europe, and the fungus is known to survive up to 5 years in wood, probably in the form of aleurioconidia. Ceratocystis fimbriata is listed as among the highest risk pathogens that could be imported into the United States on eucalyptus logs and chips from South America (Kliejunas et al., 2001). The Platanus form (C. fimbriata f. platani) is listed as an EPPO A2 quarantine pest (OEPP/EPPO, 1986).

References

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