The flight activity and movements of Myzus persicae (Sulzer) and Brevicoryne brassicae (L.) in a field cage.
Large numbers of newly flight-mature alate alienicolae of Myzus persicae (Sulz.) were flown in a flight chamber for 5 or 10 h. Flown aphids marked with fluorescent pigments took off again from potato plants inside and outside large field cages. Marking did not appear to reduce the flight capacity or survival of aphids on plants but may have made them more active than normal. Whether marked or not, large proportions of alatae that settled on potato, cauliflower or sugar-beet after long flights took off again the next day. The cages had no effect on take-off, but the proportion of alatae that made a subsequent flight was significantly affected by the length of the initial flight. Many alatae, caged on plots of potato and cauliflower, remained mobile and flight-worthy for 4-5 days. Fewer alates of M. persicae settled on cauliflower than of Brevicoryne brassicae (L.); consequently, M. persicae remained active for more days than did B. brassicae. Adult alatae of M. persicae showed no preference for the older leaves of potato plants in field cages. The significance of subsequent flight activity after the initial flight for plant virus epidemiology is discussed.