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Impact of pine looper defoliation in Scots pine

secondary attack by pine shoot beetles, tree mortality, top-kill, growth losses, and foliage recovery

Cedervind, Jan (2003). Impact of pine looper defoliation in Scots pine. Diss. (sammanfattning/summary) Uppsala : Sveriges lantbruksuniv., Acta Universitatis Agriculturae Sueciae. Silvestria, 1401-6230 ; 297
ISBN 91-576-6531-1
[Doctoral thesis]

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Widespread defoliation of forests caused by insects or fungi cause economic losses throughout the world. Successful outbreak management involves cost/benefit estimation and requires knowledge of potential yield losses. Currently, such knowledge is scarce. This thesis evaluates the significance of single-year defoliation by the pine looper moth (Bupalus piniaria L.) (Lepidoptera: Geometridae) and secondary attack by the pine shoot beetle (Tomicus piniperda L.) (Coleoptera: Scolytinae) for yield losses in Scots pine (Pinus sylvestris L.). In a seven-year study, tree mortality and growth losses were quantified after a B. piniaria outbreak with a subsequent T. piniperda infestation at Hökensås in 1996. Secondary attack by T. piniperda was also studied in a Scots pine stand at Fredriksberg, infested by Gremmeniella abietina (Lagerberg) Morelet. in 2001. Tree mortality at Hökensås mainly occurred in areas with an average defoliation intensity of 90-100%. Tree mortality averaged 25%, and the “defoliation threshold” for tree survival was found to be 90% defoliation. Tree mortality peaked two years after the defoliation event, which coincided with high levels of pine shoot beetles. Involvement of T. piniperda in tree mortality increased with time since defoliation, and tree susceptibility to beetle attack increased with increasing defoliation intensity and decreasing dominance status of trees. As foliage of trees recovered, fewer trees were susceptible to beetle attack, and ultimately, beetle attacks ended as breeding substrate was depleted. Tree susceptibility to beetle attack was a function of tree vigour and beetle density. Growth losses at the Hökensås site were a combined effect of pine looper defoliation and shoot pruning by T. piniperda. Radial, height and volume growth losses were proportional to defoliation intensity. Whereas radial growth was little affected by beetle-induced shoot pruning, height growth was severely affected by beetle-induced damage to leading shoots. Growth losses alone, excluding tree mortality, were large enough to economically justify control of the pine looper outbreak had the outbreak been prevented in 1996. At Fredriksberg, T. piniperda colonised trees that would have survived the damage caused by G. abietina. However, trees with 90-100% foliage losses died because of the damage caused by G. abietina alone, and tree survival seemed to require that trees retained at least 20% of full foliage.

Authors/Creators:Cedervind, Jan
Title:Impact of pine looper defoliation in Scots pine
Subtitle:secondary attack by pine shoot beetles, tree mortality, top-kill, growth losses, and foliage recovery
Series Name/Journal:Acta Universitatis Agriculturae Sueciae. Silvestria
Year of publishing :November 2003
Number of Pages:44
ALLI. Långström, B., Hellqvist, C. & Cedervind, J. 2004. Comparison of methods for estimation of needle losses in Scots pine following defoliation by Bupalus piniaria. Silva fennica 38, 00-00. (In press) II. Cedervind, J. & Långström, B. 2003. Tree mortality, foliage recovery and top-kill in stands of Scots pine (Pinus sylvestris) subsequent to defoliation by the pine looper (Bupalus piniaria). Scandinavian Journal of Forest Research 18, 505-513. III. Cedervind, J. & Pettersson, M. & Långström, B. 2003. Attack dynamics of the pine shoot beetle, Tomicus piniperda (Col.; Scolytinae) in Scots pine stands defoliated by Bupalus piniaria (Lep.; Geometridae). Agricultural and forest entomology 5, 253-261. IV. Cedervind, J. & Lindelöw, Å. Scots pine (Pinus sylvestris, L.) mortality caused by the fungus Gremmeniella abietina (Lagerb.) Morelet. and the pine shoot beetle (Tomicus piniperda L.). Scandinavian Journal of Forest Research 0, 00-00. (Accepted) V. Cedervind, J. & Långström, B. Growth losses and foliage recovery in Scots pine exposed to different levels of defoliation after a single-year outbreak of the pine looper Bupalus piniaria and subsequent pine shoot beetle attacks. (Manuscript)
Place of Publication:Uppsala
ISBN for printed version:91-576-6531-1
Publication Type:Doctoral thesis
Full Text Status:Public
Agris subject categories.:H Protection of plants and stored products > H10 Pests of plants
Subjects:Not in use, please see Agris categories
Agrovoc terms:bupalus piniarius, defoliation, godronia, tomicus piniperda, pinus sylvestris, damage, growth, pest insects, forest pests
Keywords:Bupalus piniaria, defoliation, Gremmeniella abietina, Tomicus piniperda
Permanent URL:
ID Code:406
Department:(NL, NJ) > Dept. of Entomology (until 061231)
Deposited By: Jan Cedervind
Deposited On:21 Nov 2003 00:00
Metadata Last Modified:02 Dec 2014 10:04

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