Fruit-Fly Outbreaks in Adelaide, Sa From 1948-49 to 1985-86 .2. The Phenology of Both Pestilent Species

Abstract

The pattern of occurrences of larvae and of trapped flies within outbreaks is different for Qfly, Dacus tryoni, and Medfly, Ceratitis capitata. For Qfly outbreaks, most flies are trapped before the first larva is found. In Medfly outbreaks, most if not all flies are usually trapped after the first larva is found. The difference is probably due to the higher efficiency of the Qfly trap. The phenology of each of the two species in Adelaide is similar to that in the areas where each is endemic, with peaks of fly catches and occurrences of larvae which mostly represent generations. For Qfly, the peaks of fly catches mostly correspond to those around Sydney, but there is no obvious spring (September-October) peak in Adelaide, possibly because of the very small total number of flies caught. For Medfly the peaks of fly catches are similar to those in Perth, except that only six flies have been caught between September and November. Medfly apparently has more generations per season in Adelaide than does Qfly, but the overall rate of increase of each species per season may be similar. Interceptions of infested fruit at road blocks suggest that there could be a single peak of