Song, J.H., Riu, K.Z., & Beattie, G.A.C. 2006 Optimum sample size and spatial dispersion of red scale, Aonidiella aurantii on an orange orchard in Australia.. Journal of Asia-Pacific Entomology 9(1): 49-54.

Notes: Two-stage sampling and geostatistical techniques for cost-effective and precise sampling were examined using red scale data that were collected from a commercial orange orchard in Kulnura, Australia in mid-summer, 2004 and 2005. The distribution pattern of red scale on a twig and a fruit well followed the negative binomial, and the degree of aggregation was higher on a fruit than a twig. The analysis of variance and two-stage sampling were used to obtain the suitable sample unit (a leaf, a twig including 2 leaves and 15 cm branch and a fruit in this study) and optimum sample size. A fruit was the most suitable than any other sample units, and a twig was better than a leaf. The optimum sample size for twigs and fruits per tree was 4 twigs (2 leaves and 15 cm branch) and 4 fruits (2 directions), respectively. The variance of primary sample unit for fruits was higher than that of secondary sample unit, but that was reversed for twigs. There was a non-linear relationship between 2 years for the density on 40 fruits of the same tree, because the Spearman rank correlation coefficient (0.84) was much higher than the Pearson's (0.29). The spatial continuity for directions of 0[degree], 45[degree], 90[degree], 135[degree], and omni-direction was similar except 90[degree] in which trees were touched with together. The autocorrelation analysis showed that omnidirectional 10m apart from each sampled tree was needed to obtain the independent data.