Flight activity of Cryptolestes ferrugineus in southern New South Wales, Australia

Abstract

Spatial and temporal aspects of flight activity of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), were investigated in a grain-growing district in southern New South Wales, Australia. This species is now considered an important economic pest in Australia due to the development of a high level of resistance to phosphine. Flight activity was monitored at 4-weekly intervals near and away from grain silos. We present data for the first time from trapping with a commercial aggregation pheromone lure (active trapping phase), as well as data on C. ferrugineus by-catch from trapping using an aggregation
pheromone lure for another species (passive trapping phase). There was a strong seasonal pattern to flight activity, with no flight detected during the winter months of June, July, or August. This appears to be primarily related to ambient temperature, with maximum temperatures above 20 °C initiating flight. Beetles were trapped both near and away from grain storages, demonstrating flight dispersal in the farm environment. The results of this study in southern New South Wales also show that C. ferrugineus beetles of both sexes are flying in the farm environment. During the passive trapping phase, the sex ratio of trapped beetles did not deviate from 1:1, but during active trapping, the sex ratio was biased to females (3:1). While more work is required, information garnered from this study provides a basis for management strategies for the control of C. ferrugineus in south-eastern Australia.