1992 Volume 36 Issue 3 Pages 196-199
The survival rate of Ceroplastes japonicus GREEN on Euonymus japonicus THUNB. was compared between two groups of test plants; one group was isolated from natural enemies by cages covered with 1-mm mesh net, and another group without cages was the control. Females of C. japonicus survived much more on test plants with cages than on controls. Active predation by larvae of Mallada boninensis (OKAMOTO) was observed from July to August on test plants without cages, but no other predators were observed. Although larvae of M. boninensis are not known to be predators of C. japonicus, it is suggested that predation by this species is a major mortality factor of C. japonicus in summer. In September and October, a large number of C. japonicus adult females moved from leaves to stems, which resulted in a decrease in the population. The main mortality factor in autumn may be failure to resettle the new infestation site.
