Patterns in flight phenologies of bark beetles (Coleoptera: Scolytinae) in commercial pine tree plantations in Uruguay

Abstract

The increasing forested area in Uruguay facilitates the establishment of exotic bark and ambrosia beetles. In 2009, the first infestation of bark beetles was officially recorded. The outbreak included Hylurgus ligniperda, Cyrtogenius luteus and Orthotomicus erosus. The objective of this study was to describe and compare the seasonal flight activity and development time of bark beetles in Pinus taeda commercial stands. Flight activity was monitored by placing interception traps from July 2012 to July 2013. Every 15 days, beetles were collected. Development time was assessed with sets of trap logs from June 2013 to June 2014 during every season. A fortnight after the presence of colonization signs was verified, trap logs were taken to the lab to be incubated. Among the three species of bark beetles captured, H. ligniperda was the most abundant, representing 57 % of the total captures,followed by O. erosus (30 %) and C. luteus 12 %). Hylurgus ligniperda was captured throughout the monitoring period, showing flight peaks during fall and winter. On the other hand, captures of O. erosus were recorded mostly during spring and summer. Cyrtogenius luteus was captured exclusively during high temperature periods. For all species recorded, log colonization date varied through seasons matching the flight period. Incubation time was strongly influenced by temperature, with shorter generations in high temperature periods. Correspondingly, differences in the duration of the subcortical phase were observed for the three species. Our study provided valuable information that can be used to adjust pruning and thinning schedules by forestry companies.