SEQUENTIAL SAMPLING OF INSECT POPULATIONS

Abstract

cf. For. Abstr. 14 (No. 484); 15 (No. 3800).] The chief advaiitage of a sequential sampling technique for estimating the density of insect populations is that a smaller sample size is usually required for a given degree or accuracy, than with the conventional sampling method. Insect populations are usually very variable, and consequently a large sample is required to give reasoiiably accurate estimates with conventional sampling methods. By using sequential sampling, the sample size can frequently be - reduced by an appreciable amount without sacrificing accuracy. A disadvantage of sequential sampling is that point estimates of insect populations cannot be obtained, since population levels are usually expressed in broad categories, i.e. light, medium, or heavy. The number of categories that are practical in sequential sampling is limited to three or four; conventional sampling is required for point estimates. KEYWORDS: insect pests \ insect pests \ sampling \ protection \ forests