Seasonal phenology of the gall-making fly Fergusonina sp (Diptera : Fergusoninidae) and its implications for biological control of Melaleuco quinquenervia

A gall-making fly, Fergusonina sp., is under study as a potential biologica l control agent of Melaleuca quinquenervia (Cav.) S. T. Blake, an invasive weed in Florida, USA. The seasonal phenology of Fergusonina sp. and its hos t M. quinquenervia was studied over 2 years in northern New South Wales and south-eastern Queensland. Fergusonina sp. populations followed an annual c ycle, with gall numbers peaking in August/September. Gall density was stron gly correlated with leaf bud density and temperature, but not rainfall. Com parison of climates in Australia across the native range of Fergusonina sp. with the climate of Miami, Florida, predicts that climate should not be a limiting factor in its establishment. The fly/nematode complex of Fergusoni na/Fergusobia sp. is compared with other gall-making agents used in biologi cal control programs. Galls are formed from primordial leaf bud and reprodu ctive structures of the plant and have many of the attributes of a moderate ly powerful metabolic sink. High gall densities could potentially suppress seed production and reduce the vigour of the tree, which would make this in sect species an effective biological control agent of nt quinquenervia.