Information Sheet

Giant Scale (Marchalina hellenica)

Detection, surveillance, and management

Giant pine scale is an that sucks the sap of pine trees. This is native to the eastern Mediterranean region and is known to occur in Crete, Georgia, Italy, Russia and Turkey.

Why is it an issue?

Giant pine scale (GPS) was reported for the first time in Australia in late 2014 in pine trees east of Melbourne and Adelaide.

To date the pest has not been found in other parts of Australia, nor has it been detected in any pine plantations. However, it poses a significant economic threat to Australia’s softwood plantation industry and amenity trees.

In Victoria, the decision was made not to eradicate giant pine scale and areas of the state remain infected. South Australia has successfully eradicated all known infected trees, and the state remains free of GPS.

GPS is slow to spread without human intervention. The movement of infected wood, mulch, and machinery is the primary way it spreads long distances.

What does giant pine scale look like?

The first sign of infection is a distinctive white, cotton- like wax secretion found in between the bark, both on the trunk and branches but may also be on exposed roots. The white exudate is dense (unlike cobweb).

The life cycle of GPS is 12 months. Following egg hatching in September to December, the first instar produced is a crawler (>1mm), followed by a second immature instar, and then the third and final mature (adult) instar. Both immature instars may be found crawling over the tree.

The eggs remain in the body of the adult female. The adult insect can be up to 12 millimetres in length. Branches of pine tree infested with giant pine scale

Biosecurity SA – PIRSA Emergency Plant Pest Hotline on 1800 084 881. [email protected]

Species of trees affected

Giant pine scale feeds exclusively on plants of the family Pinaceae. Overseas host records include the following genera and species:

 Firs: Greek fir (Abies cephalonica), Caucasian fir (A. nordmanniana)

 Spruces: Engelmann spruce (Picea engelmannii), Oriental spruce (P. orientalis)

: Turkish pine (), Aleppo pine (P. halepensis), Caucasian pine (P. kochiana, P. sosnowskyi), Corsican pine (P. laricio), Black pine (P. nigra), Stone pine (P. pinea), Scots pine (P. sylvestris).

In Victoria and South Australia, giant pine scale has been found on:

 Aleppo pine (Pinus halapensis)

 Stone pine (Pinus pinea)

2  Radiata pine (Pinus radiata)

 Blue Spruce (Picea pungens).

Caucasian fir (A.nordmanniana) Blue Spruce (Picea pungens) Aleppo pine (P. halepensis)

Non-host trees

Trees which may look similar to pines, spruces, and firs, but are not hosts of giant pine scale, include cypress pines, hoop pines and she-oaks.

Surveillance

Giant pine scale is most likely to be spread through human assistance; the focus of any surveillance program should be areas where host material, machinery, or people may be moved. Infections are likely to be on the trunk of the tree (primary contact with infected material).

High-risk pathways are areas where the public congregate, e.g. ovals, parks, sporting grounds, stadiums, golf courses, parks – which are also areas commonly attended by intrastate and interstate visitors.

While surveillance for the pest can occur year-round, new infections are likely to be detected in spring/summer as eggs hatch and crawlers start to find new feeding sites. There is a bloom (lots of feeding sites) of exudate on the tree with the bright white waxy secretion easily seen from a distance.

Detection

Detection in an urban environment can be challenging due to the number of trees and distribution across the landscape. Infection is likely to be from the transport of or eggs from an infected site to a residential property that has host trees close to a car park or unloading point at the house. Infections may also occur following recent work on or around host trees by arborists or landscapers.

Where infections are established, surveillance should also move to canopy searches to account for the possible movement of the pest via possums or birds. Canopy searches should cover trees that are approximately 500m out from the Infection Point (IP).

In a plantation environment, the high-risk areas are public rest points, camping grounds, walking or bike trails, machinery movement pathways, and sites where rubbish is illegally dumped.

The visual inspection of host trees is carried out by looking for the white exudate on the trunk of the tree or branches in the canopy. In most cases, it is evident as the exudate is very white and stands out on the dark trunk. The tree should be viewed at a 45-degree angle allowing for the detection of the white exudate hidden in the cracks and behind the bark.

3 If detected, the exudate should be initially inspected for the presence of bright yellow insects and establish if the characteristics are consistent with the presence of giant pine scale. If giant pine scale is present or if in doubt contact PIRSA’s Biosecurity SA division on the Exotic Plant Pest Hotline 1800 084 881.

The extent (time) of infections can be estimated by the amount of exudate on the tree/s.

 One to ~ten spots of exudate is Tree trunks infested with giant pine scale likely to be from crawlers that have established on the tree in the first year. These will be at the base of the trunk where no other Infection Point (IP) is present in the immediate area.

 Several hundred or thousand exudate spots around the trunk and established over one-third of the tree is likely to be in the second year following adults producing eggs.

 Exudate extending up most of the tree and into the branches is likely to be seen in the third and fourth year.

 Beyond this, most of the tree including the canopy, will be covered in exudate and can also establish on exposed roots or neighbouring trees.

How to prevent the spread of giant pine scale

Giant pine scale moves slowly within a forest or plantation environment. Females do not have wings, and the winged males are rarely seen. Following the detection of giant pine scale, anyone who has been in contact with or around the tree needs to follow good hygiene practices. Further surveillance should stop until decontamination has occurred. Good hygiene is particularly important when moving between states and regions within South Australia.

The area around the tree should be fenced off, and a notice advising of the risk of spreading giant pine scale posted.

Control or treatments

There are limited effective control options due to the size of infected trees and the low efficacy of insecticides on the insect as it has a protective exudate.

At present, tree removal is the only permanent and effective treatment option. Further information can be found on the Victoria Department website (http://agriculture.vic.gov.au/) which has developed a range of informative resources for contractors and residents living with GPS.

4 Residents and landholders

The location of infected tree/s and ownership will influence treatment options. Local councils can actively remove or manage any infected trees on land within their control in order to protect remaining tree assets. While local councils are unable to effect controls on private properties, the plantation forestry industry is keen to engage in managing the risk. Each situation will be different with consideration of cost, timing, and risk.

Once detected, appropriate fencing should prevent public access to the area under the trees canopy. Humans and machinery remain the biggest risk of spreading of the pest.

The pine plantation industries are concerned about any Trunk of pine tree infested with giant pine scale detections within South Australia as they pose a significant Photo: Victorian Department of Economic risk. Industries will work with landholders to facilitate quick Development, Jobs, Transport and Resources removal of infected tree/s.

Residents and landholders need to manage the risk of spread between GPS detection and tree removal; further spread must be reduced. There is a range of things you can do to help.

 Keep fallen or cut tree branches on your property.

 Cut any infested branches that hang over the house or structures like sheds, tanks, swings, and fences.

 Do not park under or near infected trees. Prevent twigs, cones or leaves falling onto equipment that may be moved, e.g. trailers, trucks, and caravans.

 Dispose of unwanted tree branches, needles, and pinecones using your green waste bin. Avoid transporting waste to council transfer station or if unavoidable bag or cover waste during transport).

 Clean all plant material off gardening equipment using an 80% methylated spirits to 20% water solution and a brush or paper towel.

Contractors working with infested trees

When working on infested trees, it is important to practice good plant and equipment hygiene to avoid spreading giant pine scale to other properties.

 Develop a comprehensive biosecurity plan that reduces the risk of spread when removing trees. The plan should include hygiene, transport, containment, decontamination and disposal. Consider each step and its possible risk of spreading the pest further.

 Talk with the local council about decontamination options and car wash sites for large pieces of equipment.

 Cover all loads during transport.

5  Stumps or exposed roots that are not removed must be covered with plastic (solarisation) to seal in the insects, leave in place for at least one summer period to allow the stump or roots to dry up and starve the insect.

 Following tree or stump removal cover, the area in a heavy mulch 100mm+ thick. Any remaining tree roots close to the surface can become infected and will remain an active feeding site for a long period (<6 months) while the tree dehydrates and dies.

 Take a hygiene kit with you containing paper towels, 80% methylated spirits to 20% water solution, a bristle brush, disinfectant wipes, plastic bags, and spare clothes. Products such as VirkonS™ is a multi-purpose disinfectant that can be used in foot baths and to disinfect non- sensitive equipment.

 Clean and decontaminate equipment between trees using the methylated spirit solution or disinfectant wipes.

 Clean and decontaminate your machinery, tools, and clothing (or change into spare clothing) before leaving the site.

 Avoid working on jobs with host pine trees immediately after removing infected trees (>2 weeks) where possible.

If you are working with host trees which have no known infections of giant pine scale, it is still vital that you employ industry hygiene best practices. It is particularly important when moving between states and regions within South Australia.

What is the impact?

Reports from Europe indicate that large populations of giant pine scale can cause severe dehydration and dieback of branches. In some cases, this is followed by tree death.

The pest has also caused defoliation of pines in parts of Italy and Turkey, with a significant impact in urban and forest environments.

Magnified Giant Pine Scale Reporting Photo: Andrea Battisti, Universita di Padova, Bugwood.org If you think you have found giant pine scale in a host tree, please report it to Biosecurity SA by either:

 emailing a photo to [email protected]

 contacting the Emergency Plant Pest Hotline on 1800 084 881.

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