Improved forest regeneration by triggering the induced defense of conifer seedlings against bark-feeding insects

Abstract

Trabajo presentado en Estocolmo (Suecia) entre el 29 de junio y el 3 de julio de 2015.Only in Sweden 360 million conifer seedlings are planted each year but a substantial proportion of these are killed by pine weevils (Hylobius abietis) and black spruce beetles (Hylastes cunicularius). A high survival rate is essential for a high primary production of forest raw materials and biomass. There is currently no suitable non-insecticide plant protection option for a large part of these seedlings. One option may, however, be to trigger the seedlings´ own induced defense by treating them with a plant activator at the nursery so that they are prepared when they later becomes attacked by pine weevils in the field. The induced defense is under natural conditions generally expressed after damage by, e.g. a pest insect, whereas constitutive defenses are permanently present. Constitutive defenses serves to inhibit an initial attack whereas the induced defense serves to actively and vigorously stop the attack. The induced defense is powerful but the time lag after an initial attack before the induced defenses are fully expressed may be detrimental for a plant when the pest pressure is high. This weakness of the induced defense can be circumvented by applying a plant activator to trigger the induced defense of the plant before it is exposed to attacks. There is a suitable plant activator to trigger the induced defense of conifers available. That is methyl jasmonate which is a substance that also is produced naturally when a plant is attacked. It triggers the production of traumatic resin channels and different types of chemical defense substances. In this talk I will present some recent results related to the potential of this method to protect conifer seedlings against pine weevils.Peer reviewe