Whitefly-transmitted geminiviruses of tomato in the Americas
A paper on whitefly-transmitted geminiviruses in tomato in the Americas has recently been published by Polston ; Anderson (1997) and gives many interesting details on the economic impact, etiology, distribution and expansion, case histories, ecology and epidemiology, and management of these diseases. This paper focuses on tomato diseases, but cucurbits and beans are also severely affected by whitefly-transmitted geminiviruses. Since the late 1980s, most of the tomato-producing areas of Florida, Caribbean, Mexico, Central America, Venezuela and Brazil are suffering high incidences of geminiviruses with devastating economic consequences. With the introduction and spread of Bemisia tabaci biotype B (EPPO A2 quarantine pest), the number of previously unreported geminiviruses has increased significantly. Until the mid or late 1980s, only Chino del tomate (Mexico: Sinaloa), tomato yellow mosaic (Venezuela) and tomato golden mosaic geminiviruses (Brazil: São Paulo) were reported on tomato crops in the Americas. However, at present approximately 17 different viruses are described. At this point, it can be useful to note that one difficulty is that geminiviruses are primarily identified by their genomic sequence and there is a lack of consensus on a method to distinguish strains from isolates, and strains from species. Characterization, and even documentation, is still lacking for many of these newly observed geminiviruses and this has led to a certain confusion.
Spread of Bemisia tabaci biotype B
B. tabaci biotype B is thought to have been introduced into the Americas on ornamentals from Europe. By the late 1980s, biotype B had established and displaced the indigenous populations in Texas and Florida (USA). By 1990, the same occurred in Arizona and California (USA). It was then found in Antigua and Barbuda, Dominican Republic, Grenada, Guadeloupe, Puerto Rico, Trinidad and Tobago, Saint Kitts and Nevis, Mexico (Quintana Roo*). By 1991, it was in Mexico (Sonora*), Belize and Nicaragua*. By 1993, it was present throughout most of Central America and Brazil (Distrito Federal*, São Paulo*, Parana*, Rio de Janeiro*, Bahia*, Pernambuco*). By 1994, it was in Venezuela, Mexico (Sinaloa*, Tamaulipas*) and has just been found in Colombia*. (New detailed records are marked with an asterisk).
Tomato geminiviruses in USA
Although the existence of weeds with golden mosaic symptoms was known since the 1950s and the presence of B. tabaci was observed since at least the end of the 1800s, geminiviruses were not a problem in USA. The situation changed in 1989, when tomato mottle geminivirus appear in Florida. It is thought that high populations of B. tabaci biotype B were first noted in 1987. Incidence of tomato mottle geminivirus was sometimes very high (up to 100 %), but since 1994 growers are using imidacloprid against the vector which has lowered considerably the incidence of the disease. Tomato mottle geminivirus was also found in Virginia (on few plants), South Carolina and Tennessee. It is present in Puerto Rico.
Texas pepper geminivirus was first seen in tomato and pepper in Texas in 1987. Outbreaks lasted only for a few years in Texas. However, the disease is still important in Tamaulipas (Mexico).
Pepper huasteco geminivirus was detected in pepper in USA in 1987. It was also found on tomato in Mexico. However, there are only few reports of this virus in USA, as well as for Serrano golden mosaic geminivirus which was found on pepper and tomato in Arizona.
Tomato geminiviruses in Mexico
Symptoms caused by Chino del tomate geminivirus were seen in Sinaloa since 1970s. Symptoms can be particularly severe compared with most geminiviruses. In Sinaloa, it was found on tomato and pepper. This virus was recently observed in Chiapas, Morelos and Tamaulipas. It can occur in mixed infections with pepper huasteco and Texas pepper geminiviruses.
Outbreaks of Texas pepper geminivirus occur routinely in tomato and pepper in Tamaulipas.
Pepper jalapeño geminivirus which was found in Sinaloa and other Mexican States on pepper is thought to be a strain of Texas pepper geminivirus.
Several other geminiviruses have been reported in Mexico: Sinaloa leaf curl, tomato leaf crumple (may be a strain of Chino del tomate), Serrano golden mosaic (closely related to Texas pepper and pepper jalapeño), rizado amarillo and tigré disease.
Tomato geminiviruses in Central America
Venezuela
A disease later known to be caused by tomato yellow mosaic geminivirus was first seen in Venezuela in 1960s, and constituted a limiting factor in tomato production.
In 1997, a strain of potato yellow mosaic was found on diseased tomatoes (however, the sequence of the tomato virus was slightly different from the sequence of the virus on potato).
Brazil
Tomato golden mosaic geminivirus caused problems in tomato as early as in the 1960s. Recent surveys failed to detect it, but many other geminiviruses are now found.
In Minas Gerais, 2 different geminiviruses (called Tom GV1 and Tom GV2) were found and are closely related to tomato golden mosaic and bean golden mosaic geminiviruses.
In São Paulo, tomato yellow streak and several other different geminiviruses were isolated on tomatoes from Rio de Janeiro, Bahia, Pernambuco and Distrito Federal.
Tomato geminiviruses in the Caribbean
In Dominican Republic, geminiviruses started to appear on tomato in 1988. Symptoms of what would be later recognized as tomato yellow leaf curl geminivirus were first seen in 1992. It is believed that it was introduced in the north-west of the island by a tomato grower with transplants from Israel. The virus was identified as TYLCV-Is in 1994. It is also present in Cuba and Jamaica.
Potato yellow mosaic geminivirus appears widespread in the Caribbean and its distribution is probably expanding. It was first described on potato in Venezuela in 1986. In 1992, symptoms of chlorotic mottling, leaf distortion and leaf rolling were seen for the first time on tomato in Martinique, in 1993 in Guadeloupe and 1994 in Puerto Rico (Polston et al., 1998). An almost identical virus was observed in Venezuela on tomato. Similarly, potato yellow mosaic geminivirus has been found in tomato in Trinidad and Tobago with high disease incidence. Relationships between potato yellow mosaic and tomato yellow mosaic geminiviruses are not known.
The following simplified table extracted from the paper of Polston ; Anderson (1997) summarizes the situation of tomato geminiviruses in the Americas.
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Virus
|
Known distribution
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Symptoms on tomato
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Chino del tomate (CdTV)/Tomato leaf crumple geminivirus (TLCrV)
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Mexico (Chiapas, Morelos, Sinaloa, Tamaulipas)
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Severe leaf curling, leaf rolling, vein thickening, yellow mosaic, stunting, reduced fruit set
|
|
Pepper huasteco geminivirus (PHV)
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Mexico (Guanajuato, Quintana Roo, Sinaloa, Taumaulipas), USA (Texas)
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Vein clearing, mild leaf distortion, chlorosis, stunting
|
|
Potato yellow mosaic geminivirus (PYMV)
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Guadeloupe, Martinique, Puerto Rico, Trinidad and Tobago, Venezuela
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Chlorotic mottle, leaf rolling, leaf distortion
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|
Serrano golden mosaic geminivirus (SGMV)
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Mexico (Sinaloa), USA (Arizona)
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Leaf curling, leaf distortion, stunting
|
|
Sinaloa tomato leaf curl geminivirus (STLCV)
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Mexico (Sinaloa)
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Foliar chlorosis and purpling, leaf curling, shortened internodes
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|
Taino tomato mottle geminivirus (TTMoV)
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Cuba
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Rugosity, leaf deformation and curling, stunting
|
|
Texas pepper (TPV)/Pepper jalapeño geminivirus (PJV)
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Mexico (Coahuila, Sinaloa, Tamaulipas), Guatemala, USA (Arizona, Texas)
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Mosaic, leaf curling, stunting
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|
Tomato geminivirus BZ-Ub
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Brazil (Minas Gerais)
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Yellow mosaic
|
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Tomato geminivirus BZ-Ig
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Brazil (Minas Gerais)
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Yellow mosaic
|
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Tomato golden mosaic geminivirus (TGMV)
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Brazil
|
Yellow mosaic
|
|
Tomato mottle geminivirus (ToMoV)
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Puerto Rico, USA (Florida, South Carolina, Tennessee, Virginia)
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Chlorotic mottle, leaf curling, plant stunting, reduced fruit size and number
|
|
Tomato yellow leaf curl geminivirus (TYLCV)
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Cuba, Dominican Republic, Jamaica
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Reduced leaf size, chlorotic margins, chlorotic mottling, flower abscission, severe plant stunting
|
|
Tomato yellow mosaic geminivirus (TYMV)
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Venezuela
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Yellow mosaic, leaf curling, stunting
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Tomato yellow mottle geminivirus (ToYMoV)
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Costa Rica
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Chlorotic mottle, leaf distortion, leaf curling, stunting
|
|
Tomato yellow vein streak geminivirus (ToYVSV)
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Brazil (São Paulo)
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Yellow mosaic, wavy leaves
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Tom GV1 geminivirus
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Guatemala, Honduras, Nicaragua
|
Severe leaf curling, light leaf mottling or chlorosis
|
|
Tom GV2 geminivirus
|
Guatemala
|
Not reported
|
Sources
Polston, J.E.; Anderson, P.K. (1997) The emergence of whitefly-transmitted geminiviruses in tomato in the Western Hemisphere.
Plant Disease, 81(12), 1358-1369.
Polston, J.E.; Bois, D.; Urbino, C. (1998) Occurrence of a strain of potato yellow mosaic geminivirus infecting tomato in the Eastern Caribbean.
Plant Disease, 81(12), p 126.