snytbaggeFigure 1. Pine weevil (Hylobius abietis)In this project, we apply novel approaches to increase the knowledge base necessary to develop novel ways of managing the pine weevil in Swedish forestry. The research foci of the participating groups will be used in a complementary way to study parasite resistance in Populus – where we can capitalize on infrastructure already developed - to get a deeper basic understanding of the genetics of parasite resistance in trees and demonstrate how the underlying polymorphisms can be identified.
Superior Populus genotypes for potential use in Swedish forestry can also be developed. In addition, we will with equal emphasis study the attack of the pine weevil (Hylobius abietis) (Figure 1) on conifers. The pine weevil is the economically most important pest for forest regeneration in Sweden. We will, in the short time perspective, try to develop a pine weevil management strategy based on natural or synthetic chemical compounds.

As the genomic resources for conifers are likely to advance rapidly over the next five years we believe that in a somewhat longer time frame (2015-2020), the same basic approaches that we will develop for Populus in this project will be available for application in conifers (Figure 2). At this point, the knowledge we have gained from working with Populus will allow for the development of pine and spruce material which are more resistance against pine weevils and other pests.

Today´s forest management leads to optimal conditions for the pine weevil. Larval development in roots of fresh conifer stumps – and this food resource becomes about equally large each year by forest harvesting. The pine weevils are long-distance fliers (up to 100 km) (Figure 3) that easily locate fresh clearcuts in the landscape. Seedlings with a weak defense are planted on the clearcuts as "candies" for the weevils. We will investigate novel ways of "pre-treating" the seedlings before planting, and test whether these methods will influence the behaviour and food choice of the weevils. We will for example perform two-choice tests for testing of anitfeedant substances (Figure 4), as well as arena experiments for multi-chioce tests of volatile substances (Figure 5)

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Figure 2 Structure of the project   Figure 3 Flying pine weevil (Hylobius abietis)
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Figure 4 Two-choice test with antifeedant substance vs. control   Figure 5 Arena with 16 traps for multiple-choice tests of volatile substances

In the work will Populus, we study naturally occurring herbivores on the only Swedish Populus species, aspen. We relate the herbivore preferences to aspen defence compounds, for example phenolic glucosides, and will use the parallel aspen genomics project to demonstrate how informative genetic markers for resistance towards the herbivores best can be obtained.