Final Report: Monitoring and control techniques for Australian bug
Icerya purchasi Maskell (Hemiptera: Monophlebidae) (Australian bug) is a polyphagous and cosmopolitan pest of plants that includes citrus. Dense populations of Australian bug cause plant stress, leading to defoliation, fruit drop and a decrease in plant vitality. Australian bug excretes honeydew, which supports the growth of sooty mould, disfiguring the plant. Novius cardinalis (Mulsant) and Novius iceryae (Jenson) (Coleoptera: Coccinellidae) (Vedalia beetles) are natural enemies of the Australian bug that are generally successful in controlling their populations. Vedalia beetles are, however, susceptible to a number of insecticides used to control other insect pests in citrus orchards. High incidences of Australian bug were recently recorded in mandarin orchards in some citrus growing regions in South Africa. In order to better understand the causative factors leading to an increase in incidence of Australian bug, populations of Australian bug and Vedalia beetles were monitored on a monthly basis over two years (May 2021 – May 2023) in four mandarin orchards on four different farms in Mpumalanga Province, South Africa.