Burrawangs Besieged? Insect pests appear to be spreading

Scale insects are killing plants in some areas

Burrawangs – Macrozamia communis – are an iconic feature of the South Coast landscape, often forming an understory to that other icon, spotted gum. In 2010 severe dieback of burrawangs was reported in Murramarang National Park – caused by a scale insect. Recently a stem borer has also been causing some plant damage. INaturalist has played a key role in advancing our knowledge of the spread and identity of these insects.

Scale Insect – Aspidiotus murramarangensis

In 2021 McDougall et al published a study of cycad dieback in Murramarang National Park, north of Batemans Bay. They concluded the culprit was an unnamed scale insect, closely related to Aspidiotus nerii. In 2011 infestations were confined to a small area between Dark Beach and North Head, by 2019 it had spread across Murramarang National Park, and to the settlement sof Depot Beach and Peblly Beach. They concluded that infestation was less in previously burnt areas.

The scale appears to have spread, now widespread at Long Beach and appearing at Lilli Pilli in 2022, and more recently near Potato Point. In 2022 Benjamin Normark described the species, naming it afte rthe park where it was first reported – an entomologist from Massachussetts, Normark has identified all sighting logged on iNaturalit.

Stem borer – Siraton internatus

A stem borer weevil was first seen in Rosedale in February 2019, and identified by New Zealand taxonomist Samuel Brown. It has since been logged at Lilli Pilli and Surf Beach, and would appear to be spreading. Nothing mor eis known, except that it is having a singificant impact on plants