Tomato leaf curl virus
Have you seen tomato leaf curl virus symptoms?
Be on the lookout for these symptoms and report them to Biosecurity Queensland.
Early detection and reporting of symptoms are the key elements in controlling the disease.
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Tomato leaf curl virus belongs to a group of viruses which cause a range of destructive plant diseases worldwide. These viruses are constantly evolving and threaten horticulture in many of the world's tropical and subtropical regions. Tomato leaf curl virus (TLCV) and tomato yellow leaf curl virus (TYLCV) are the most damaging.
|Where does it occur?|
Two viruses from this group occur in Australia. An Australian strain of TLCV is restricted to the northern parts of Queensland and the Northern Territory. The southern-most detection in Queensland has been in Mossman.
An exotic strain of TYLCV was detected in areas south of Brisbane and around Bundaberg early in 2006.
|Symptoms and damage|
Plants are stunted or dwarfed. Leaflets are rolled upwards and inwards. Leaves are often bent downwards and are stiff, thicker than normal, have a leathery texture and often have a purple tinge to the veins on the underside. Young leaves are slightly chlorotic (yellowish). Flowers appear normal. Fruit, if produced at all, are small, dry and unsaleable. Affected plants tend to be distributed randomly or in patches.
TLCV can be confused with several other tomato disorders such as tomato big bud, tomato yellow top, physiological leaf roll and phosphate and magnesium deficiency.
|Spread of TLCV|
Tomato leaf curl viruses are not transmitted in seed, soil or from plant to plant by handling. They stay in infected plants, some of which may be weed plants that do not show symptoms. The viruses are transmitted between plants by silverleaf white fly (SLW), Bemisia tabaci biotype B, which is a horticultural pest in coastal and some inland districts of Queensland and New South Wales. SLW is an established pest in Western Australia and cotton production systems in Queensland. (See silverleaf whitefly).
Tomato (Lycopersicon esculentum) is the host plant on which tomato leaf curl viruses are commonly expressed in the field. However, the range of host plants that can be infected differs between the viruses, and not all hosts show symptoms of infection. Numerous host plants have been experimentally infected with TLCV under glasshouse conditions:
In affected areas, control of tomato virus epidemics will depend on control of whitefly infestations. On-farm practices are particularly important where older crops are infected with tomato virus and also have high whitefly populations. Unless whiteflies on older infected crops are controlled, they may move to younger plantings and infect them with TLCV. More information is available on whitefly management in the publication Best Management Strategies for Silverleaf Whitefly in Vegetable Crops by Siva Subramaniam, Paul De Barro and Alison Shields.
There are two key points to managing the spread of TLCV:
The best chance of achieving this is through good farm management and farm hygiene practices: