Five-spined bark beetle
Native to the Americas, the five-spined bark beetle (Ips grandicollis) is now an established pest in Queensland's pine growing regions. Populations are usually managed through good forest cultivation practices and natural predators. They are also under biological control by 2 introduced parasitoid wasps.
Managing the five-spined bark beetle is important because the pest spreads blue stain fungi, which can severely affect the value, quality and aesthetic quality of milled timber.
- Five-spined beetle
- Eastern five-spined engraver
- Adult beetles are dark red-brown to almost black.
- 3-5mm long.
- May be shiny or dull, hairless or densely covered with hairs or scales.
Similar species mainly attack the stumps or roots of dead trees, slashing waste on the ground, or large areas of debris from tree clearing, including:
- golden haired bark beetle (Hylurgus ligniperda)
- black pine bark beetle (Hylastes ater).
Bark beetles are destructive forest pests, posing significant biosecurity threats to Australia, including:
- southern pine beetle (Dendroctonus frontalis)
- mountain pine beetle (D. ponderosae)
- western pine beetle (D. brevicornis)
- red turpentine beetle (D. valens)
- European spruce bark beetle (Ips typographus)
- pine shoot beetle (Tomicus piniperda).
Widely distributed throughout Queensland's plantations of southern pine and the tropics since 2009.
- Pinus species, including commercially grown southern pines (and hybrids):
- slash pine (P. elliottii)
- Caribbean pine (P. caribaea var. hondurensis).
- Can populate in damaging numbers in thinnings and clear-fell plantation debris and in fire-damaged or stressed, standing trees.
- Can kill trees if population numbers are very high and/or if trees are weakened by drought or fire. In southern Australia, 'feeding attacks' by newly emerged adult beetles have also been recorded in young plantations adjoining areas of cleared trees.
- Carries blue stain fungi, which can affect the value and aesthetic quality of milled timber.
- Populations in Australia have caused large-scale mortality of drought-stressed pine trees. As droughts and fires may increase with climate change, managing this pest may become more important.
- At Beerburrum, Queensland in 1994, this pest caused $10 million in destruction to fire-damaged trees.
- Adults bore into the outer bark of trees or woody debris (slash). Clusters of males produce a chemical pheromone that attracts more beetles to the attack site.
- Males initially form a nuptial chamber in the bark, and typically admitting 3-5 females.
- Beetles carry spores of blue-stain fungi, which grow in the tree sapwood and phloem (food conducting tissue, just under the bark).
- Females excavate long tunnels, shaped like tuning-forks in the phloem.
- Larval tunnels, tightly packed with frass (waste) fan out from the main tunnel.
- Larvae pupate in chambers constructed in the bark.
- Newly-emerged adults feed briefly under the bark before emerging and restarting the cycle.
- Four or more generations are achieved per year in south-eastern Queensland, which means that populations can increase rapidly with favourable resources.
Monitoring and action
- Use appropriate harvesting practices, for example, reducing slashing debris and removing logs quickly off-site.
- Control is effected by 2 introduced biological control agents, the parasitoid wasps Roptrocerus xylophagorum and Dendrosoter sulcatus.
- Pests may also interfere with the monitoring and control program for sirex wood wasp in New South Wales by attacking sirex trap trees, preventing wood wasp attacks and reducing the program's effectiveness. The program's success depends on early detection and biological control to prevent outbreaks. Research is underway to find ways to manage this problem.
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018