Abstract
In Tottori Prefecture, some foresters cultivate ginseng radixes, Panax ginseng in woods. Some investigations had been carried out on the pests damaging the ginseng radixes and revealed that the larvae of a weevil, Dermatoxenus caesicollis seriously damaged the radixes. This study was carried out on the seasonal prevalence of adult emergence and the ovipositional characteristics of this weevil. The adults emerged from early May to late Octover. The number of adults was estimated to reach a peak in middle or late May by Petersen's method. The longevity of the adults fed on the leaves of Aralia cordata was 74.2±50.5 days(mean±SD). The female pasted the leaves by adhesive matter released from herself and laid eggs (960 on average, min.: 2, max.: 3911) in masses among them. The mean size of egg masses was 26.6 eggs(min.: 1, max: 186). The mean egg periods was 12.5 days. The hatchabilities were more than 90% in almost egg masses.
