BIOLOGY AND HOST-SPECIFICITY OF PLATPHALONIDIA-MYSTICA (LEP, COCHYLIDAE) INTRODUCED INTO QUEENSLAND TO BIOLOGICALLY CONTROL PARTHENIUM-HYSTEROPHORUS (ASTERACEAE)

Platphalonidia mystica (Razowski & Becker) has been studied as a poten tial biological control agent against parthenium weed (Parthenium hyst erophorus L.). During host specificity testing, larval feeding damage occurred on sunflower (Helianthus annuus L.) and to a lesser extent on Dahlia sp., but risk of damage to sunflower crops under field conditi ons is considered negligible. In view of the very great problem that P . hysterophorus is causing, and the threat of its continued southward spread into Southern Queensland, New South Wales and Victoria, field r elease of P. mystica was authorised and commenced in Queensland in lat e 1992.