Insect pests of exotic pine plantations
Pine-killing wood wasp (Sirex noctilio)
Insect-damaged pine needles
Pests that can reduce the commercial productivity of exotic pine plantations include:
- pine-killing woodwasp (Sirex noctilio)
- Monterey pine aphid (Essigella californica)
- five-spined bark beetle (Ips grandicollis).
Pine-killing woodwasp
The following is an excerpt from a report by Michael Cole, DAFF.1
Sirex generally attacks stressed pine trees. Wasp numbers sufficiently high to cause significant attack do not generally develop in vigorous healthy stands, but this has been known to happen. In South Australia and Victoria between 1987 and 1989, the Sirex wasp killed more than 5 million Pinus radiata trees (with a combined value of $10-12 million).
The National Sirex Control Strategy program facilitates an integrated pest management approach based on ensuring low Sirex wasp populations, through the maintenance and release of virulent strains of the introduced nematode Beddingia siricidicola, as well as a range of parasitoid wasps, as biological controls. The program also encourages optimum plantation thinning practices and site selection to minimise the occurrence of stressed trees in high-risk areas. Regular trapping and surveillance programs monitor Sirex levels. Controls are implemented to avoid major outbreaks.
Monterey pine aphid
The Monterey pine aphid, first observed in Australia in 1998, is able to infest a range of pine species and has since been detected in most pine-growing areas in all states.
So far, mild to severe defoliations have been recognised in P. radiata plantations in Victoria, NSW and South Australia, but the effects on growth yield are still to be assessed. Aphid levels are being regularly monitored in most states, using standard foliage beating methods during surveys.
Five-spined bark beetle
Ips grandicollis is a serious pine bark beetle pest accidentally introduced to Australia from the northern hemisphere. It is able to infest all plantation pine species grown in Australia. The beetle has been present in Australia for at least sixty years and occurs in all mainland states and the Australian Capital Territory, but is absent from Tasmania.
Pheromone traps are used to monitor beetle presence and beetle numbers in some states. Population levels build up primarily on fresh logging debris or in damaged or severely stressed standing trees. The beetle is also able to transport blue stain fungi.
A range of parasitoids have been introduced into Australia to limit beetle numbers.
1Source of the above information: M Cole, 'Forest invasive species strategies in Australia - country report', 2005. In: P McKenzie, C Brown, S Jianghua & W Jian (eds), The unwelcome guests. Proceedings of the Asia-Pacific forest invasive species conference, RAP publication Food and Agriculture organisation of the United Nations.
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