Monitoring European pine sawfly population densities with pheromone traps in young pine plantations

Field trials utilizing pheromone traps were evaluated to develop a populati on monitoring and predicting system for the European pine sawfly (Neodiprio n sertifer). Larval density was censused in a transect across each study si te. Three traps per site were bailed with 100 mu g of (2S,3S,7S)-3,7-dimeth yl-2-pentadecyl (diprionyl) acetate. During a two- year period traps loaded with 1, 10 and 100 mu g of diprionyl acetate were compared. Correlations a nd coefficients of determination between numbers of captured males and larv ae of the same or successive generations were seldom high. Between-generati on relationships were significant, when population density was increasing. Having years with increasing densities in a row, the present monitoring met hod might provide warning of an outbreak. (C) 1999 Elsevier Science B.V. Al l rights reserved.