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Development and validation of a phenology model for forecasting the population dynamics of the spruce web-spinning sawfly, Cephalcia abietis

Project Leader
Schafellner Christa, Project Leader
Duration:
01.04.2019-30.09.2021
Type of Research
Applied Research
Staff
BOKU Research Units
Institute of Forest Entomology, Forest Pathology and Forest Protection
Funded by
Stiftung 120 Jahre Universität für Bodenkultur, Gregor Mendel-Strasse 33, A-1180 Wien, Austria
Abstract
The spruce web-spinning sawfly, Cephalcia abietis, is a primary pest with irrgular gradations in European mature spruce forests. Mass outbreaks are difficult to predict because the insect spends several years as a prepupa (resting larva) inside an earth‐walled chamber in the soil. Increasing temperatures due to climate change may shorten the generation cycle (voltinism) of the sawfly, probably resulting in more frequent outbreaks and higher damage on spruce in the near future.
Our model sawfly population in the northern part of the Waldviertel/Lower Austria has a 3-year-population cycle. Since the last outbreak in 2013, this population is permanently monitored. The next mass swarming of the wasps is expected for spring 2019. With the necessary number of insects available, we will determine the thermal sums for individual stages of sawfly development and establish a phenology model in order to predict the population dynamics from air and soil temperatures and use it as a practical and simple monitoring tool to forecast sawfly mass outbreaks.
Keywords
Forest entomology;
Cephalcia abietis; Development threshold; Degree-days; Climate change; Modelling;
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