Etiology and control of the following Tomato diseases: Tomato Mosaic Virus
Tomato Mosaic Virus:-
Pathogen:-
> Tomato mosaic virus (ToMV) is a member of family tobamoviridae and belongs to the genus tobamovirus, which is a plant pathogenic virus.
> It is found worldwide and affects tomatoes and many other wide host range plants including many agricultural crops and weeds such as tobacco and beans, all of which can serve as inoculum sources.
> The tomato crop is highly susceptible to the Tomato mosaic virus (ToMV).
> The symptoms vary from tiles, wrinkle, reduction and curvature of leaflets, and irregular ripening of fruits.
> This disease requires attention because of its easy dissemination by contact, cultural practices, or contaminated seed.
Symptoms:-
> Tomato mosaic virus symptoms can be found at any stage of growth and all parts of the plant may be infected.
> ToMV causes yellow mosaic symptoms on the leaves and tomato fruits.
> Tomato mosaic virus symptoms are seen as a general mottling or mosaic appearance on foliage.
> Light and darker green mosaic leaf mottle, sometimes with distortion of younger leaves; this is the most common reaction in summer in glasshouses.
> In winter, with low light intensity, short days and temperatures not above 20°C, plants are often severely stunted and leaves distorted to ‘fern-leaf’ or tendril shape, but mottling may be slight.
> Plants are less vigorous, and fruit yield is reduced by 3 to 23%.
> Tomato mosaic virus strains occur in Chenopodium murale in the USA, causing severe stunting, distortion and necrosis, and in pear associated with a diffuse chlorotic leaf spotting.
Management:-
> Treating mosaic virus is difficult and there are no chemicl controls like there are for fungal diseases.
> Tomato mosaic virus has been found to survive for up to 50 years in desiccated plant detritus! So tomato mosaic virus control then leans less on eliminating the disease and more on reducing and eliminating the virus sources and insect infestations.
> Control is mainly based on the use of virus-free seeds.