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Tomato Leaf Curl Virus (ToLCV)

Tomato Leaf Curl Virus (ToLCV) is the collective name for a complex of single-stranded DNA begomoviruses (family Geminiviridae) that infect tomato (Tomato Crop) across India. It is one of the most economically important diseases of tomato in tropical and sub-tropical India and is responsible for major losses in the rainy-season crop in particular.

Identification and symptoms

Infected plants show upward curling and crumpling of leaves, severe stunting, leaf wrinkling and yellowing of leaf margins. Internodes are shortened and the plants develop a bushy, dwarfed appearance. Fruit set on infected plants is drastically reduced or absent; early infection causes near-total yield loss.

Host crops and life cycle

ToLCV is transmitted in a persistent circulative manner by the whitefly Bemisia tabaci - the same vector responsible for Okra Yvmv and numerous other begomovirus diseases of vegetables. A single whitefly can transmit the virus after a minimum acquisition feed of around 30 minutes, and females are more efficient vectors than males. The virus does not transmit through seed or by mechanical sap inoculation under normal conditions.

Damage and economic impact

In heavy whitefly seasons the disease can wipe out commercial tomato fields, and is a primary reason why summer/off-season tomato cultivation under shade-net (Summer Tomato Cultivation) is increasingly preferred over open-field monsoon crops in vulnerable regions.

Management

Integrated management combines whitefly control through insecticides, reflective mulches and UV-absorbing nets, adjusted planting dates to escape peak vector populations, and use of tolerant cultivars. India has released several tolerant open-pollinated cultivars including Sankranthi, Nandi and Vaibhav (2003-04). Many modern private-sector hybrids are bred for tolerance to leaf curl as a selling trait.

See also: Tomato Crop, Okra Yvmv, Tomato Early Late Blight, Summer Tomato Cultivation, Tomato Variety Sahoo, Tomato Variety Aryaman Seminis, Tomato Variety Salaar.

References

  1. Leaf Curl Disease: A Significant Constraint in Tomato Production in India. IntechOpen.
  2. Tomato Leaf Curl Virus. ScienceDirect topic overview.