Ips typographus (L.) pheromone trapping in south Alps:: spring catches determine damage thresholds

Ips typographus is one of the major forest pests in the Italian Alps. From 1996, populations of I. typographus in Friuli-Venezia Giulia region (NE Italy) have been permanently monitored in areas of outbreak by using pheromone traps. At the same time, damage caused by the insect was estimated annually. Preliminary analysis of the data (1996-2002) reveals some interesting information: (i) the flight activity of I. typographus is very extended and occurs over a period of about 4 months (May to August); (ii) there is a high correlation between mean captures per trap and annual damage; (iii) there is a high correlation between spring captures (May to mid-June) and total captures (May to August), and between spring captures (May to mid-June) and annual damage. The correlation between spring captures and damage allows the determination of a reliable risk-damage threshold (about 5000 beetles/trap, in spring), reducing at the same time, the monitoring period and the general costs.