Ecology of alien populations S. noctilio and its biological control agents in NW Patagonia

DEBORAH FISCHBEIN; JUAN CORLEY; JOSÉ MARÍA VILLACIDE; MARÍA VICTORIA LANTSCHNER

Annapolis

Congreso; 30th USDA Interagency Research Forum on Invasive Species; 2020

USDA Forest Service

For pine plantations in the Southern Hemisphere, the non-native woodwasp Sirex noctilio is allegedly the most important pest. The species is present attacking many planted pines in climatically different regions, although it is during population outbreaks that harm becomes notorious. In the invaded range, much work has focused on S. noctilio biological control through the introduction of parasitoids and a parasitic nematode. However, as population growth is central to S. noctilio damage and can also affect its geographical spread, knowledge on the ecological drivers of population dynamics of this forest pest is essential to successful pest management. We present our results on a correlative study of outbreaks observed for this species in pine plantations of NW Patagonia (Argentina) at different spatial scales, and how this may affect the success of bio-control practices deployed. We show that aggregation, and exposure to water stress are key predisposing factors that may lead to positive density-dependent growth, in turn limiting the ability of natural enemies to regulate populations. Together, our results try to reinforce the importance of research on the population dynamics of alien forest insects to help improve our abilities to prevent and control damaging outbreaks.