A survey of insects attacking seed cones of Pinus cembra in the Alps, the Pyrenees and Massif Central

Abstract

The composition and impact of the entomofauna exploiting seed cones of Swiss stone pine (Pinus cembra L.) was surveyed in native stands and plantations of France, Italy, Switzerland and Austria during 1992-1996. A total of 2785 cones were collected from 25 sites. The cone entomofauna consisted of five species, of which three (Dioryctria abietella, Eupithecia abietaria, Cecidomyia pini) were regularly observed. The two other insects, Polydrusus atomarius and Zeiraphera diniana were observed on first-year cones, and only in two stands. No spermatophagous insect was detected. None of these insect species could be considered specific to cones of P. cembra. The overall damage never exceeded 40% of the cone crop. The importance of cone damage varied with year, cone abundance, and the position of the tree in the stand. The cone entomofauna of Swiss stone pine largely deviated from that recorded in cones of other high altitude conifers but resembled that of other stone pines growing in Eurasia. The question: why cones of P. cembra were less damaged by insects than those of other alpine conifers is discussed.