Experiments were conducted to determine distance between sample points to obtain independent samples of corn rootworm eggs and larvae. Spatial patterns and spatial dependence of egg and larval distributions were investigated using geostatistics at two different spatial scales: field scale with sampling distance of 20–25 m and plot scale with 0.2-m sampling distance. Field-scale egg distribution showed no spatial dependence, indicating a random distribution. In the plot-scale study, egg distributions of two plots were random but one plot exhibited spatial dependence that explained 89% of the spatial variability. Larval distribution showed spatial dependence at both field and plot scales and 49.7–99.7% of spatial variability was explained by spatial dependence. This study reported that the distance to obtain independent samples of egg densities would be >25 m for field-scale egg sampling and >0.4 m for plot-scale egg sampling. Independent larval estimates would be produced by spacing samples >46 m apart for field-scale larval sampling, and >1.0 m apart for plot-scale larval sampling.
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Journal of the Kansas Entomological Society
Vol. 79 • No. 2
April 2006
Vol. 79 • No. 2
April 2006
corn rootworms
Diabrotica spp
geostatistics
spatial distribution