Analisi della distribuzione spaziale e campionamento delle ovideposizioni di Tortrix viridana L. (Lep. Tortricidae)

Analysis of spatial distribution and sampling of Tortrix viridana L. (Lep. Tortricidae) egg-clusters in Sardinian oak woods - The spatial distribution of Tortrix viridana L. egg-clusters was investigated during thewinter of 1999 in eight forest areas of Quercus pubescens Willd. in central Sardinia. A three-stage sampling was adopted: 8 one-hectare plots per area, 8 trees per plot, 4 terminal branches per tree. The Kuno's method was used to define a sampling design to estimate the population abundance. The optimum allocation of sampling effort corresponds to: 2 branches per tree; 4 trees per plot; the number of plots to sample per area is to be 5 if the required precision (mse/mean) is 25%, 8 with a precision of 20% and 33 for a precision level of 10%.