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PEST MANAGEMENT OF DOUGLAS-FIR TUSSOCK MOTH: ESTIMATING LARVAL DENSITY BY SEQUENTIAL SAMPLING

Published online by Cambridge University Press:  31 May 2012

R.F. Shepherd
Affiliation:
Pacific Forest Research Centre, Canadian Forestry Service, 506 West Burnside Road, Victoria, British Columbia, Canada V8Z 1M5

Abstract

A sequential sampling system for early-instar Douglas-fir tussock moth larvae based on beating 3 lower branches from each of a number of trees is described. The relationship between lower- and mid-crown insect densities is given. The number of samples required to assess moderate insect densities using a fixed level of precision and at low insect densities using a critical density level is presented. The system is designed to be used during the early stages of an outbreak in stands not previously defoliated.

Résumé

On décrit une méthode d'échantillonnage séquentiel pour la capture des larves des premiers stades de la chenille à houppes du Douglas, par battage des branches inférieures d'un certain nombre d'arbres. On donne le rapport entre la densité des larves dans le bas et le milieu de la cime. On indique le nombre d'échantillons requis pour évaluer des densités modérées au moyen d'une précision déterminée et les densités faibles au moyen d'un seuil de densité critique. La méthode est conçue pour servir au début d'une infestation, dans des peuplements qui n'ont jamais été défoliés.

Type
Articles
Copyright
Copyright © Entomological Society of Canada 1985

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