Investigating the Impact of Planting Date and Cotton Aphid Management on the Final Incidence of Cotton Leafroll Dwarf Virus.

Cotton leafroll dwarf virus (CLRDV) is an emerging aphid-transmitted virus in the U.S.  Understanding the timing of virus spread to the crop, and the significance of transmission events on final virus incidence is needed to reduce the number of unnecessary insecticide sprays for cotton aphid.  Characterizing the role of primary spread (transmission that occurs as a result of aphids moving into the crop from the surrounding landscape) versus secondary spread (the transmission that occurs as populations of vectors within the crop grow and spread throughout the field) on final virus incidence will identify the importance of aphid population management on reducing crop losses.  In pathosystems where secondary spread is a significant factor contributing to final virus incidence, management of vector populations can reduce damage and losses.  The age of the crop at the time of infection is also an important factor that influences crop susceptibility, symptom severity and economic losses. Research was conducted in AL and GA in 2019 to: 1) Determine whether or not aphid management practices reduce final incidence of CLRDV, 2) Identify timing of primary spread of CLRDV into research plots, and 3) Monitor aphid dispersal into cotton plots to identify timing of flights, and the species of aphids present in cotton agroecosystems.