Spatial dynamics of a Sirex noctilio woodwasp population within a pine plantation in Patagonia, Argentina

The woodwasp Sirex noctilio F. (Hymenoptera: Siricidae) is probably the most important pest of pine tree plantations of the southern hemisphere. We studied the spatial arrangement of an endemic population of the woodwasp S. noctilio within pine plantations located in northwest Patagonia, Argentina, during three successive years since colonization. By censusing healthy and attacked trees, which provided data on current and past yearly woodwasp attacks, we studied: (i) the spatial pattern of attacked trees during the endemic phase of a woodwasp population, and (ii) the changes in the spatial arrangement through time and with an increasing (i.e., no intervention) pest population. Among a total of 53 649 counted trees, attack rates were low during the study period (accumulated attack below 0.5%). Results of spatial statistical analysis showed that woodwasp attack is highly clumped, and that spatial aggregation increases with time, even with increasing numbers of attacked trees. The observed spatial arrangement, a consequence of a demographic process, can have important implications for the management of woodwasp populations and contributes to our understanding of the nature of outbreak population behaviour in this pestiferous forest insect.EEA BarilocheFil: Corley, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; ArgentinaFil: Villacide, Jose Maria. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; ArgentinaFil: Bruzzone, Octavio Augusto. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Bariloche. Grupo de Ecología de Poblaciones de Insectos; Argentin

Invasive Insects in Forest Plantations of Argentina: Ecological Patterns and Implications for Management

In the last decades, growing international trade and tourism have significantly increased the rate at which non-native species reach new ecosystems. Plantation forest systems in Argentina are especially exposed to alien insects partly because they are dominated by pines and eucalypts which have been introduced to produce timber and pulp, based, among other things, on the benefits related to the lack of native herbivores (i.e., the ?natural enemy release hypothesis?). As noted worldwide, with rising numbers of invasions by nonindigenous forest insects, strong negative economic and ecological impacts on the invaded ecosystems often come along. Notably, the most damaging non-native forest insects found in plantation forestry in Argentina are common to other areas and regions of the Southern Hemisphere, which cultivate similar tree species. By focusing on processes behind described patterns of arrival, establishment, and spread of alien forest insects in commercial forests of Argentina, we explore broad ecological patterns involved in their invasion success and how these may affect strategies of alien pest management.Fil: Corley, Juan Carlos. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; Argentina. Universidad Nacional del Comahue. Centro Regional Universitario Bariloche. Departamento de Ecología; ArgentinaFil: Villacide, José María. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; ArgentinaFil: Lantschner, María Victoria. Instituto Nacional de Tecnología Agropecuaria. Centro Regional Patagonia Norte. Estación Experimental Agropecuaria San Carlos de Bariloche. Instituto de Investigaciones Forestales y Agropecuarias Bariloche. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones Forestales y Agropecuarias Bariloche; Argentin