Sampling Argentine stem weevil,Listronotus bonariensis(Kuschel), populations in pasture: The soil-dwelling stages

摘要

Previously described sampling systems for the soil-dwelling stages of the Argentine stem weevil,Listronotus bonariensis(Kuschel), are briefly reviewed. Sampling and extraction techniques developed and extensively tested by the authors are described. A manually operated 75 mm diam. soil corer was used for field sampling. A mechanical method was used for the rapid and large-scale extraction of adult, pupal. and prepupal stages from soil cores. The method gives acceptable recovery rates for all these stages. Taylor's powerlaw analysis was performed on sample mean and variance estimates of adult and prepupal plus pupal stages, and used to develop numerical sampling equations. A sampling plan is described for sampling populations to attain specific levels of precision at different population densities.