Pine weevil

Project: Control of forest insect pests; Antifeedants for the pine weevil; Hylobius abietis

We have identified organic anti-gnawing compounds that can protect pine and spruce seedlings from being lethally gnawed on, based on compounds in the frass/faeces from pine weevil females.

Facts about the project

Project leader
Rikard Unelius, Linnaeus University
Other project members
Björn Bohman, Sacha Legrand, (Lnu), Göran Nordlander, Henrik Nordenhem, (SLU) Ultuna Anna-Karin Borg-Karlson, (KTH,) Kerstin Sunnerheim, Uppsala University (UU)
Participating organizations
Linnaeus University, Kalmar, Sweden (Lnu), Swedish University of Agricultural Sciences, Uppsala, (SLU), Sweden Royal Institute of Technology, Stockholm, Sweden, (KTH), Uppsala University, Uppsala, Sweden, (UU).
The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning
Ecological chemistry (Department of Chemistry and Biomedical Sciences, Faculty of Health and Life Sciences)

More about the project

Antifeedants for the pine weevil; Hylobius abietis The pine weevil, Hylobius abietis, is a big problem in the Swedish forests. A long research project aimed to prevent their attacks by smartly utilizing the insects own signaling system.

In collaboration with SLU, Uppsala biologists, we have shown through chemical and biological trials that the frass (boring material mixed with feaces) as the females cover laid eggs with discourages other female from laying their eggs right there. One hypothesis is that this prevents competition for food for the offspring. This was of interest as an oviposition pheromone, but was also tried as a gnawing deterrent.

After several years of isolation and identification work in combination with the testing of hundreds of purchased and synthesized substances, we have shown that there are several substances that have good anti-feedant effects in the lab environment. In order for it to work outside the field, the substances must be active for at least one year and not affect the plant. Furthermore, within the project, we also had to find and develop a matrix in which we could solve the substances and then apply them to the plant in the nursery schools. The matrix must withstand strong cold without cracking and strong heat without melting. It must be flexible and allow expansion of the plant's stem. The matrix development led to a spin-off discovery, that fine sand grain in the matrix discouraged the weevils from gnawing. This lead to the commercial product Conniflex, a type of mechanical protection for the seedlings to be planted. This product is used commercially now on hundreds of millions plants per annum. Any anti-gnawing compound is not incorporated in this product as the cost to register a plant protection chemical in Europe is extremely high.

The project is part of the research in the Ecological chemistry group