Legislative Council: Wednesday, September 27, 2023


Giant Pine Scale

The Hon. J.S. LEE (Deputy Leader of the Opposition) (14:40): I seek leave to make a brief explanation before asking a question of the Minister for Primary Industries regarding giant pine scale.

Leave granted.

The Hon. J.S. LEE: Giant pine scale has the scientific name of Marchalina hellenica, and is an insect that sucks the sap of pine trees, posing a threat to our softwood plantation industry. According to the PIRSA website, adult scale are able to carry 400 eggs in their bodies and those eggs are hatching right now, between September and December. An infestation of giant pine scale was reportedly the cause of the felling of trees in north-east Adelaide, in the popular locations of Elliston Reserve, near the Hope Valley Reservoir, and Highbury. To date, 483 trees have been removed. My questions to the minister are:

1. Can the minister inform the chamber when the giant pine scale was initially detected in Adelaide?

2. When did felling of the infected trees begin in order to halt the outbreak?

3. Can the minister table any evidence that the felling has halted the outbreak?

The Hon. C.M. SCRIVEN (Minister for Primary Industries and Regional Development, Minister for Forest Industries) (14:41): I thank the honourable member for her question. Giant pine scale has previously been detected in Victoria and South Australia but hasn't been detected in other parts of Australia. To date, just for members' interest, it has not been detected in any commercial pine plantations.

It is native to the eastern Mediterranean region and it causes branch dieback, gradual desiccation and tree death. It feeds exclusively on plants from the pine family, such as pines, firs and spruces. Earlier this year, detection was made in pine trees within SA Water's Hope Valley Reservoir Reserve, which is an area that is not accessible to the public. As per previous response operations, I am advised around 120 trees were felled and heaped, including infested and adjacent pine trees.

Back in 2017, it was agreed nationally that giant pine scale could not be eradicated from Australia. This is due to a couple of different reasons: in part, because there are ineffective chemical controls for the pest, and also because it is very difficult to detect in the early stages of infestation when it is in low numbers at the top of tall trees.

At that time, I am advised, PIRSA consulted with the forestry industries and agreed that implementing border controls for the pest would be too impactful on the industry given the amount of pine material that travels between Victoria and South Australia. With this being the case, it is very likely that more infestations of giant pine scale will continue to be found in South Australia.

Due to the endemic status of the giant pine scale in Australia, PIRSA Biosecurity does not initiate an eradication response to the pest and management of giant pine scale rests with land managers, landowners and industry.

Accordingly, PIRSA coordinated a meeting of industry stakeholders—I believe it was around about 30—to share information about the detection and formed a working group to coordinate surveillance and management activities. Working group members included representatives from the Department of Primary Industries and Regions, SA Water, ForestrySA, the City of Tea Tree Gully, the Australian Forest Products Association, UniSA, National Parks and Wildlife Service South Australia, and an independent expert.

Further detections have since been found in nearby Highbury. Staff from the Department of Primary Industries and Regions are working closely with local government and the forest industry to determine if the pest has spread further. ForestrySA is playing a key role in coordinating tree removal and mulching machinery because they see the benefit in preventing the current infestation from spreading into managed forests. They have been driving the process for the Department of Primary Industries and Regions, providing oversight and technical support.