THE IMPACT OF FORAGING ANTS ON POPULATIONS OF COCCUS-HESPERIDUM L. (HEM., COCCIDAE) AND AONIDIELLA-AURANTII (MASKELL) (HEM., DIASPIDIDAE) IN AN AUSTRALIAN CITRUS GROVE

The impact of honeydew-seeking ants (Iridomyrmex rufoniger gp. spp.) o n citrus canopy populations of the honeydew-producing soft scale insec t, Coccus hesperidum, and the non-honeydew-producing armoured scale, A onidiella aurantii, was evaluated during two seasons in southern New S outh Wales. Numbers of C. hesperidum and A. aurantii were substantiall y greater (3-12 times) in trees containing foraging ants than in trees from which ants were excluded. It is likely that I. rufoniger gp. spp . protects both scale species by disrupting the activity of natural en emies. Effective control of honeydew-seeking ants appears to be a prer equisite for biological control-based management of honeydew-producers in Australian citrus groves.