March 10, 2006
From: ProMED-mail<promed@promedmail.org>
Source: Jamaica Gleaner (jamaica-gleaner.com) [edited]
<http://www.jamaica-gleaner.com/gleaner/20060309/eye/eye1.html>


Since the 1990s, the production of some vegetable crops in Jamaica has been reduced due to whitefly-transmitted geminiviruses. Geminiviruses are plant viruses that cause epidemics in food crops.

More than 20 viruses from Jamaica infecting vegetables (6 viruses) and weeds (18 viruses) have been identified by the GSI (geminivirus scene investigators) at the Biotechnology Centre at the University of the West Indies.

The crop viruses include bean golden yellow mosaic virus (BGYMV), which infects red peas and broad beans causing a yellow mosaic pattern on the leaves. This virus is the major limiting factor in red pea production, accounting for a 60 per cent reduction in red peas in Jamaica since 1993. This has resulted in the importation of red peas to meet local market demands.

2 geminiviruses -- tomato yellow leaf curl virus (TYLCV) and tomato mosaic Havana virus (ToMHV-[JM]) -- were found infecting tomato and scotch bonnet pepper. Symptoms include leaf curling and severe stunting. TYLCV is the most devastating virus infecting tomato. TYLCV alone, or with ToMHV-[JM], causes the 'Jherri curl' disease in Jamaica. There are several tolerant tomato varieties in Jamaica including Gempride, Gempear and Adonis and farmers are advised to plant these instead of susceptible ones such as Castlerock and Flordale.

Cabbage leaf curl disease:
2 geminiviruses cause cabbage leaf curl disease (CaLCD) in cabbage and cauliflower. Cabbage plants infected with CaLCD have leaves that curl up instead of folding into a compact 'head' which means the farmer has no marketable product. Farmers in Douglas Castle indicated cabbage varieties such as Resist Crown and Tropicana are tolerant to the disease and should be planted by farmers instead of susceptible varieties such as KY and KK. There are data which suggest that the cabbage viruses also infect broccoli and this is being investigated by the GSI.

In Jamaica, numerous weeds, including milkweed and broomweed, are infected with geminiviruses. Some scientists have suggested that many of the viruses in the crops may have evolved from the weed viruses.
In Jamaica, some weed viruses are able to infect crops in the laboratory and this is being investigated by the GSI.

--
ProMED-mail
<promed@promedmail.org>

[The vegetable crop plants tomato (_Lycopersicon esculentum_), pepper (_Capsicum annuum_), red peas a.k.a. cowpeas (_Vigna unguiculata_ ssp. _unguiculata_), broad (faba) beans (_Vicia faba_) and cabbage (_Brassica oleracea_) in Jamaica are shown here to be susceptible to several different geminiviruses (family: _Geminiviridae_, genus: _Begomovirus_) transmitted by whiteflies (_Bemisia tabaci_). This is the general case throughout subtropical and tropical cropping areas wherever whiteflies are active.

Epidemics are driven by a highly efficient flighted vector that is active for long periods of the year combined with a ready source of virus pathogen in both weeds and infected crops, both of which are reservoirs for these destructive viruses. The article recognizes the increasing ability of national laboratories to correctly diagnose and
distinguish between the many different geminiviruses using specific molecular probes.

Some selected ProMED-mail posts are listed below, but there are too many related citations in ProMED-mail archives to list all of them in "see also:". Most can be found by searching for "geminivirus OR begomovirus" in the message area (more than 80 hits).

Map: Jamaica
<http://worldatlas.com/webimage/countrys/namerica/caribb/jm.htm>

Links, including disease maps and disease pictures.
Cabbage leaf curl virus:
<http://gemini.biosci.arizona.edu/viruses/calcuv/>
Bean golden mosaic virus:
<http://gemini.biosci.arizona.edu/viruses/bgymv/index.html>
Tomato yellow leaf curl virus:
<http://gemini.biosci.arizona.edu/viruses/tylcv/index.htm>
Tomato mosaic Havana virus
<http://gemini.biosci.arizona.edu/viruses/tomhv/index.htm>
- Mod.JAD]

[see also in the archive:
Yellow leaf curl, tomato - Multicountry: 1st reports 20060304.0702
2001
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New begomoviruses, tomato 20010530.1051
Begomoviruses, tomato - Nicaragua 20010514.0937
2000
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Tomato dwarf leaf curl virus - Jamaica 20000503.0669
1998
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Tomato yellow leaf curl begomovirus: spreading 19980528.1026]