INTRODUCTION

The manipulative use of Chrysopidae as biological control agents in Australia is in its infancy. The family is well represented, with slightly more than 50 species described (New, 1996), but many of these are recorded only infrequently in Australia and occur almost entirely in forests and other naturally vegetated habitats. Many are also limited in their distribution within Australia. The species encountered most frequently in southern Australia are Apertochrysa edwardsi (Banks), Mallada innotatus (Walker), M. signatus (Schneider), and Plesiochrysa ramburi (Schneider). Indeed, a survey of Chrysopidae on native Acacia trees over three years in Victoria yielded only three species (A. edwardsi, M. signatus, P. ramburi), with A. edwardsi by far the most abundant (New, 1983). However, this species is predominantly arboreal, and has not been reported commonly on field crops. Apertochrysa edwardsi is Bassian, the two Mallada species are widespread in Australia, and P. ramburi occurs over much of the western Pacific region, where its larvae have been reported from many crops. The larvae of all these species were described by Boros (1984), but many details of their biology have not been clarified, and there are few records of their prey or feeding activity. However, they are clearly the most likely candidates among Australian Chrysopidae for investigation for their potential in biological control.

This note considers the potential for one of these common species, M. signatus, as a species currently attracting considerable attention as a polyphagous predator on pests of field crops.

ROLE IN BIOLOGICAL CONTROL

In eastern Australia, Mallada signatus is commonly found only in small numbers on field crops.