Ecological Entomology (2001) 26, 8-15

Pierluigi Bonello, William R. Mcnee, Andrew J. Storer, David L. Wood and Thomas R. Gordon (2001)
The role of olfactory stimuli in the location of weakened hosts by twig-infesting Pityophthorus spp.
Ecological Entomology 26 (1), 8-15
Abstract: 1. Senescing, shade-suppressed, or broken branches of Monterey pine Pinus radiata are infested by twig beetles in the genus Pityophthorus (Coleoptera: Scolytidae). The studies reported here tested whether twig beetles can discriminate between healthy and pitch canker-diseased branches, whether diseased branch tips produce more ethylene than undamaged controls, and whether ethylene and other volatiles, produced by the plant in response to tissue damage, are utilised by twig beetles in host location.
2. Significantly greater numbers of twig beetles were reared from pitch canker-symptomatic than from pitch canker-asymptomatic branches of Monterey pine collected in the field.
3. Needles of Monterey pine branches inoculated with the pitch canker fungal pathogen Fusarium circinatum produced significantly higher levels of ethylene than needles of control branches, and this was evident just prior to, and during, symptom expression.
4. In trapping studies in which pheromone production was prevented, there was no evidence of attraction of twig beetles to a source of ethylene alone, to cut host branches, or to cut branches treated with the ethylene-releasing compound, ethephon. The results suggest that twig beetles identify weakened branches after landing.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Thomas R. Gordon, Andrew J. Storer, William McNee

Research topic(s) for pests/diseases/weeds:
environment - cropping system/rotation
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Pityophthorus (genus)	Pine (Pinus)	U.S.A. (SW)
	Fusarium circinatum	Pine (Pinus)	U.S.A. (SW)