Plant Virus and Viroid Diseases in the Tropics - Volume 1: Introduction of Plant Viruses and Sub-Viral Agents, Classification, Assessment of Loss, Transmission and Diagnosis

pPlant virus and sub-viral pathogens pose severe constraints to the production of wide range of economically important crops worldwide.� The crops raised both through true seed and vegetative propagated materials are affected with number of virus and virus-like diseases. The virus may enter into plants through seed planting materials or by vectors.� Once the virus is in the field, it multiplies and spreads following definite patterns depending upon the nature of the vector and agro-meteorological conditions.� Disease free crops and plants are great economic and social importance in feeding the world's population.
Detection of virus and sub-viral agents at initial stages of infection is critical to reduce economic losses.� For nearly two decades, ELISA and its variants played a major role in large scale virus testing and also in the production of virus-free planting materials./p