New Phytologist (2015) 205, 1128-1141

Sigrid Netherer, Bradley Matthews, Klaus Katzensteiner, Emma Blackwell, Patrick Henschke, Peter Hietz, Josef Pennerstorfer, Sabine Rosner, Silvia Kikuta, Helmut Schume and Axel Schopf (2015)
Do water-limiting conditions predispose Norway spruce to bark beetle attack?
New Phytologist 205 (3), 1128-1141
Abstract: - Drought is considered to enhance susceptibility of Norway spruce (Picea abies) to infestations by the Eurasian spruce bark beetle (Ips typographus, Coleoptera: Curculionidae), although empirical evidence is scarce. We studied the impact of experimentally induced drought on tree water status and constitutive resin flow, and how physiological stress affects host acceptance and resistance.
- We established rain-out shelters to induce both severe (two full-cover plots) and moderate (two semi-cover plots) drought stress. In total, 18 sample trees, which were divided equally between the above treatment plots and two control plots, were investigated. Infestation was controlled experimentally using a novel 'attack box' method.
- Treatments influenced the ratios of successful and defended attacks, but predisposition of trees to infestation appeared to be mainly driven by variations in stress status of the individual trees over time. With increasingly negative twig water potentials and decreasing resin exudation, the defence capability of the spruce trees decreased.
- We provide empirical evidence that water-limiting conditions impair Norway spruce resistance to bark beetle attack. Yet, at the same time our data point to reduced host acceptance by I. typographus with more extreme drought stress, indicated by strongly negative pre-dawn twig water potentials.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
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Database assignments for author(s): Sigrid Netherer, Axel Schopf

Research topic(s) for pests/diseases/weeds:
resistance/tolerance/defence of host

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Ips typographus	Spruce (Picea)	Austria