大発生時のスギドクガ幼虫密度と被害葉量について

概要

論文の詳細を見る
A severe outbreak of the Sugi tussock moth, Dasychira argentata BUTLER was observed in 1978 on approximately 200 ha of Sugi (Cryptomeria japonica D.DON.) and Hinoki (Chamaecyparis obtusa S.and Z.) stands in Sakurai, Nara Prefecture. The full-grown larval density in late July estimated by the frass drop method showed 5,843,000/ha in Sugi and 395,000/ha in Hinoki. The dry weights of the eaten leaves/ha/day, obtained from correlations between the eaten leaves and the amount of frass, were estimated at 562.7kg in Sugi and 44.0kg in Hinoki. The dry weight/ha/day of fallen leaves shed because of the infestation was 52.6kg in Sugi and 1.5kg in Hinoki. Therefore, the total dry weight/ha/day of defoliated leaves was estimated at 615.3kg in Sugi and 45.5kg in Hinoki. The leaf biomass of the infested Sugi stand was estimated at about one metric ton/ha. As the leaf biomass of a normal Sugi stand in Nara Prefecture is about twenty metric tons, the defoliation rate was regarded in this case to be about 95 percent.
日本森林学会の論文
1980-10-25