Vol. 11, Issue 3 (2022)

Author(s):
Subaya Manzoor, Baby Summuna, FA Bhat, Shaheen K Jan, PA Sheikh, Vikas Gupta, Addafer Gulzar and WA Dar

Abstract:
Viral diseases rank second in terms of monetary losses after fungal diseases and provide a major challenge to agriculture worldwide. Climate change, rapid population increase and food insecurity are driving rapid alterations in agricultural system that favour destructive viral disease outbreaks. Viruses alter physiology of infected plants, results in symptom development that ultimately lead to huge yield loss, estimated to be more than 30 billion dollars annually (Jones, 2021). Emerging Geminiviruses cause economic losses estimated as: 1300–2300 million dollars in cassava (Africa), 300 million dollars for grain legumes (India), 140 million dollars in tomato (Florida) and 5 billion dollars in cotton (Pakistan) (Varma and Malathi, 2003). The economic losses due to viral diseases complicate food security and may pose a significant threat to mankind. Keeping all this in sight there is a robust got to investigate and understand virus ecology and epidemiology for developing any management programme for any viral disease. Ecology mainly focuses on virus behaviour in its habitat while as epidemiology focuses on viral diseases within host populations (Wilson, 2014).Discovery of cause of potato leaf roll disease in Netherland, importance of insect vectors, understanding of virus vector transmission (Harrison, 1980) and effectiveness of predictive modals (Jones et al., 2014) were major mile stones in the advancement and development of plant virus ecology and epidemiology field. Both the areas are multi-layered with many variables having influence on host plants, viruses and the vector behaviour mostly having damaging effect but some may have beneficial effect as Cucumber mosaic virus offers cold resistance in sugar beet (Xu et al., 2008). Vectors have a major role in virus transmission (Gallet and blanc, 2018). Viral diseases are due to specified molecular interactions via protein among virus and vector, understanding such interactions can support approaches for shielding plants from contamination by meddling virus take-up and transmission (Dietzgen et al., 2016). Climatic changes have diminished effectiveness of cultural management practices and virus epidemics have become less predictable (Jones, 2014). Due to climatic change previously unknown viruses and vectors emerged, their introduction threatens both cultivated as well as newly introduced crops (Jones and Barbetti, 2012). The utilization of new molecular techniques have significantly speed up the pace of progress in understanding all the factors underlying this discipline. Numerous advantages that are provided by studying molecular epidemiology and ecology include improving the recognisability of plant virus populations, providing information about virus epidemic patterns not possible by conventional field examinations, knowledge regarding the virus resistance breakdown and testing the strength of virus or vector specific control measures (Jones, 2014). Rapidly increasing technological innovation is giving a significant means to address the problems that plant virus epidemics pose to future food security and the diversity of the earth’s remaining vegetation and ensures that the subject has a very exciting nature.