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​​APS Full-Day Forum

​​​​​[Factors affecting] Changes in virus prevalence over time in different crop types

​Broadcast Date: Tuesday, October 12, 2021 | 9:00 a.m. –​ 5:15​ p.m. US Central Time​​​

View the On-Demand Sessions below

Meeting Schedule​


The composition of the complement of viruses infecting particular crop types has changed over time, potentially affected by factors including: the deployment of different resistance genes and emergence of resistance-breaking strains; shifts in vector distribution related to climate change or introduction of other vector host plants into the region; changes in method of crop propagation; introduction of new viruses from other growing regions in infected propagation material; changes in the prominence of previously low-impact viruses as a result of reduction of other viruses through testing and certification programs; and the emergence of previously uncharacterized viruses as a result of extending the growing area into new ecological zones with different native vegetation. Different factors may affect various crop types differently. Understanding these differences will aid virologists, diagnosticians, plant breeders, entomologists, agronomists, and quarantine officials to be prepared to deal with emergence of new viral diseases, and to better control and limit their spread.

Learning Objectives

  • Exchange of information on the factors thought to have influenced changes in virus prevalence in different crop types, and on potential means of early detection and prevention of new viral types emerging in different cropping situations through more intensive surveys of viruses present in new introductions or the native vegetation of projected areas of crop expansion. 
  • The merits of holding new resistance genes for pyramiding prior to resistance deployment to combat existing problems, etc. 
  • Discussion regarding differences in practices in different crop types will further aid preparations to mitigate future viral emergences.​


Rodrigo Valverde, Louisiana State University Agricultural Ce​nter​​​


John Hammond, USDA ARS Floral and Nursery Plant Research Laboratory​
Ioannis Tzanetakis, University of Arkansas
Rodrigo Valverde, Louisiana State University Agricultural Center​ 

​On-Demand Sessions

  • Session 1 - Understanding the factors affecting changes in virus prevalence in Prunus and Malus spp.
  • Session 2 - Viruses of cucurbit crops: a rapidly changing situation related to multiple factors, particularly to frequent virus introductions
  • Session 3 - Virus disease breakouts in citrus: A strategy of consolidation step by step
  • Session 4 - Musical chairs with tomato viruses – lessons learned in Florida and beyond
  • Session 5 - Landscape evolution of emerging grapevine viruses
  • Session 6 - Cotton viruses: past, present (and future?)
  • Session 7 - Altered virus prevalence in ornamental crops - from new crops or altered production practices?
  • Session 8 - The Status of Sweetpotato Viruses
  • Session 9 - Cassava Viruses across Africa and on to Asia
  • Session 10 - The past and present landscape of wheat viruses in the Great Plains region of the USA
  • Session 11 - Emerging and reemerging virus diseases of berry crops
  • Session 12 - Changing targets in potato virus control over time
  • Session 13 - Emerging viruses of sugarcane and grasses