Spatio-temporal dynamics of an Ips acuminatus outbreak and implications for management
Article first published online: 17 OCT 2012
© 2012 The Royal Entomological Society
Agricultural and Forest Entomology
Volume 15, Issue 1, pages 34–42, February 2013
How to Cite
Colombari, F., Schroeder, M. L., Battisti, A. and Faccoli, M. (2013), Spatio-temporal dynamics of an Ips acuminatus outbreak and implications for management. Agricultural and Forest Entomology, 15: 34–42. doi: 10.1111/j.1461-9563.2012.00589.x
- Issue published online: 22 JAN 2013
- Article first published online: 17 OCT 2012
- Accepted 16 June 2012
- Engraver beetle;
- sanitation cutting;
- spot growth;
- spot proliferation;
- Pinus sylvestris
- 1Understanding spatio-temporal processes of bark beetle infestations is crucial for predicting beetle behaviour and aiding management decisions aiming to prevent or mitigate tree mortality. We recorded the spatial and temporal distribution of killed trees during the 5-year period of an Ips acuminatus outbreak.
- 2Killed trees were always grouped in well-defined patches (infestation spots). In years of high population density, infestation spots were large and aggregated, whereas, in years of low density, infestation spots were small and weakly aggregated or randomly distributed within the study area.
- 3Most trees were killed in the spring by beetles that had hibernated but, in some years, trees were also killed in the summer by new-generation beetles originating from spring attacks. Spring-killed trees always formed new infestation spots at new locations (i.e. spot proliferation). By contrast, summer-killed trees always occurred at the edge of active spots established in the spring, thus resulting in spot growth.
- 4With regard to management strategies, the results obtained in the present study suggest that areas located in close proximity to infestations of the previous year should be prioritized for risk assessment. Because large spots account for most of the observed tree mortality, the cut-and-remove method should be focused on these spots as soon as crown discoloration appears in the summer. If applied timely, this strategy will remove the new-generation beetles originating from the spring attacks before they emerge and also reduce the risk of spot growth.