An Outbreak of Spodoptera exempta (Walker) (Lepidoptera: Noctuidae) in the Highlands of Papua New Guinea.

Abstract

An outbreak of the moth Spodoptera exempta (Walker), (the African armyworm), took place in pastures in the highlands of Papua New Guinea in March 1973. The outbreak is believed to have been the result of breeding by an influx of adults from lowland areas following successful breeding subsequent to the breaking of a severe drought in November 1972.
In the invasion area, the outbreak lasted for a single generation. The collapse of the outbreak is attributed to high mortality of the pupal stage. The main factor contributing to pupal mortality was an unidentified pathological condition superficially resembling desiccation. Parasites also contributed to pupal mortality, there being several unidentified species of tachinid and two ichneumonids, Lissopimpla scutata Krieger and Ichneumon promissorius Er .. Because of the small area of gramineae host crops at risk and the rapid regeneration of damaged pasture, little economic loss resulted from the outbreak. Feeding by larvae on Tritonia crocosmiflora (Lemoine) Nich. (lridaceae) represented a new family host record.