抄録
Pine logs on which caged Monochamus alternatus insects had deposited eggs were placed in a Pinus densiflora stand, and a carbamate insecticide, carbaryl, was aerially sprayed for a 2-year period, and survival rates were studied. Life tables were constructed from samplings conducted 5 times a year in which the mortality rates and agents were examined at each developmental stage. The survival rate from egg to adult emergence was 0.55 during the year before the spraying, and 0.37 and 0.54 in the 2 years when spraying was conducted.For populations (cohorts) established by June-July oviposition, however, the survival rate was 0.56 in the year before application and 0.87 in the 2 years with application. The comparison of mortality agents and life tables suggested that the insecticide application had suppressed the general activity of predaceous insects when and after M. alternatus reached the 3rd larval instar.
