California five-spined ips

Acetone was the primary choice of solvent because of the rapid and spontaneous crystallization characteristics of low boiling solvents (3) from which insecticides may crystallize within a few hours after application. The California five-spined ips [Ips confusus (Le Conte)] was used as the experimental bark beetle for most of the study. The probit method of Finney (16) was used to analyze time-mortality relationships. 

Ipsenol (111, Figure 4.63), ipsdienol (112) and cw-verbenol (A) were isolated and identified in 1966 by Silverstein et al. as the components of the male-produced aggregation pheromone of a bark beetle, California five-spined ips (Ips paraconfusus). 

In none of his experiments could Moeck demonstrate that primary attraction is used in host selection by the three principal species in the area Dendroctonus brevicomis (the western pine beetle), D. ponderosae (the mountain pine beetle) and Ips paraconfusus (the California five-spined engraver beetle). What Moeck s results did show, however, was that beetles landed indiscriminantly on healthy and stressed trees at about one beetle a day on each tree. Theoretically only one beetle is needed to initiate mass attack, since as soon as it releases pheromone, landing rates would increase markedly on that tree. In Moeck s study, landing rates on trees that became attacked by D. brevicomis increased to up to 800 beetles a day. 

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