Giant pine scale, (Marchalina hellenica) was reported for the first time in Australia in late 2014. It was found in pine trees in suburbs east of Melbourne and in Adelaide.
Giant pine scale has not been found in other parts of Australia, nor has it been detected in any pine plantations. However, as a sap sucking insect, it poses a threat to Australia’s softwood plantation industry.
The Department of Primary Industries and Regions South Australia has destroyed all known giant pine scale infested trees in the state. This was completed in early 2016, with the removal of 85 infested trees and the sites decontaminated.
In Victoria, it has not been possible to destroy giant pine scale. There are more than 4300 infested trees in the south east suburbs of Melbourne.
Infested trees in Victoria were treated with the insecticide imidacloprid but the chemical injection treatments did not work as effectively as expected and live scale insects remain present on treated trees.
The Consultative Committee on Emergency Plant Pests (CCEPP) considered alternative eradication options in Victoria but have concluded that giant pine scale could not be eradicated, because:
- chemical controls have shown to be ineffective
- the only other control option was to remove all infested trees, and it was unlikely that this would have been publically acceptable
- there is low confidence that the pest is detectable at very low densities
- costs would be considerably high to achieve full eradication of the pest.
The CCEPP’s recommendations were supported by the National Management Group in October 2016.
Containment and management activities
While it has been agreed that the pest cannot be eradicated from Victoria, attention to limiting the spread and managing the impact of giant pine scale in Victoria will now be the focus.
Agriculture Victoria will continue to work with the softwood industry, arborists, local government and the community to manage the pest. Restrictions on the handling and movement of giant pine scale host materials are in place in the affected areas of Victoria.
The following websites have more information:
Primary Industries and Regions South Australia
More on how we respond to outbreaks.
What you need to do
You need to be on the lookout for signs of giant pine scale infestation.
Do not touch, move or collect samples should you see any white and waxy secretions on pine, fir or spruce trees.
Report any findings to the Exotic Plant Pest Hotline, 1800 084 881. This will put you in contact with your state or territory department of agriculture or primary industries.
Other signs of giant pine scale include severe dehydration and dieback, which can lead to the eventual death of the tree.
Alternatively, if you are in Victoria you can email photos of the suspected pest to Plant Protection. In the email, please also provide your contact phone number and location of the suspected tree(s).
About giant pine scale
Giant pine scale is an insect that lives by sucking the sap of pine trees and some other trees. The insect produces white, waxy, cotton-like secretions that are visible on infected trees.
This insect prefers the lower part of the pine tree and mainly infests the main trunk but infestations may be observed on branches and sometimes exposed roots.
Large populations of the insect can cause gradual dehydration, causing the dieback of branches that eventually kills the tree.
There are no records of previous detections of this insect in Australia. It is known to occur on species of the
Pinaceae family (pines, firs and spruces) in Armenia, Crete, Georgia, Italy, Russia and Turkey.
It is not known how it got into Australia, or how long it’s been here.
Figure 1 White, waxy, cotton-like secretions in a pine tree caused by Giant pine scale
Photo courtesy of the Victorian Department of Economic Development, Jobs, Transport and Resources