An entomological radar was used to observe insect flight activity at a coastal locality in north-western Tasmania during the spring of 1973. Insects were regularly observed to take off at dusk, and local movements from nearby islands were detected on several occasions. Large-scale southward movements of insects across Bass Strait were also observed and were found to be associated with the warm anticyclonic airflows which occur ahead of a cold front. Light-trap catches indicated that the insects were noctuid moths, with Persectania ewingii (Westw.), Heliothis punctiger

Trapping data from 3 sites in southern Australia and the results of winter field rearing and laboratory studies of larval development have provided evidence in favour of the hypothesis that there is large scale wind-borne displacement of the moth, Persectaniu ewingii in spring. Possible source areas of the migratory spring moths and conditions leading to outbreaks of the pest are also considered.

No abstract