Scots pine (Pinus sylvestris L., Pinaceae) produces a terpenoid resin which consists of monoterpenes and resin acids that offer protection against herbivores and pathogen attacks. Methyl jasmonate (MJ) is a potential plant elicitor which induces a wide range of chemical and anatomical defence reactions in conifers and might be used to increase resistance against biotic damage. Different amounts of MJ (control, 10 mm, and 100 mm) were applied to Scots pine to examine the vigour, physiology, herbivory performance, and induction of secondary compound production in needles, bark, and xylem of 2‐year‐old Scots pine seedlings. Growth decreased significantly in both MJ treated plants, and photosynthesis decreased in the 100 mm MJ treated plants, when compared to 10 mm MJ or control plants. The large pine weevil (Hylobius abietis L.) (Coleoptera: Curculionidae) gnawed a significantly smaller area of stem bark in the 100 mm treated plants than in the control or 10 mm treated plants. The 100 mm MJ treatment increased the resin acid concentration in the needles and xylem but not in the bark. Furthermore, both MJ treatments increased the number of resin ducts in newly developing xylem. The changes in plant growth and chemical parameters after the MJ treatments indicate shifts in carbon allocation, but MJ also affects plant physiology and xylem development. Terpenoid resin production was tissue‐specific, but generally increased after MJ treatments, which means that this compound may offer potential protection of conifers against herbivores.

International audienceThe species composition of ophiostomatoid fungi associated with Ips typographus was studied in the Vosges, Alps and Massif Central regions of France. In each region, damage caused by bark beetles has increased during recent years. For this study, beetles were collected individually by hand from freshly attacked trees and crushed in healthy Picea abies logs. Fungi were isolated from log phloem and sapwood, and identified. The most frequently found species were Ophiostoma bicolor, O. penicillatum, Ceratocystiopsis minuta and Ceratocystis polonica. Results are discussed in terms of differences between locations and in relation to previous investigations in which populations of spruce bark beetle have been sparse. The potential role of associated fungi in the population dynamics of the spruce bark beetle is discussed.Champignons Ophiostomatoides associés au scolyte de l'épicéa, Ips typographus, dans trois régions françaises. La composition spécifique des champignons Ophiostomatoides associés à Ips typographus a été étudiée dans trois régions françaises, Vosges, Alpes et Massif Central, dans lesquelles les dommages dus aux Scolytes s'étaient récemment accrus. Les insectes ont été récoltés individuellement sur des arbres fraîchement attaqués, puis écrasés dans des rondins frais d'épicéa. Les champignons ont ensuite été isolés du liber et de l'aubier des rondins, et identifiés. Les espèces les plus fréquemment rencontrées ont été Ophiostoma bicolor, O. penicillatum, Ceratocystiopsis minuta et Ceratocystis polonica. Les résultats sont discutés en termes de différences entre localités, et en liaison avec des investigations plus anciennes réalisées sur des populations éparses. Le rôle potentiel des champignons associés dans la dynamique des populations d'I. typographus est discuté