Environmental Entomology (1998) 27, 1463-1468

Patrick K. O'Rourke, Eric C. Burkness and William D. Hutchison (1998)
Development and validation of a fixed-precision sequential sampling plan for aster leafhopper (Homoptera : Cicadellidae) in carrot
Environmental Entomology 27 (6), 1463-1468
Abstract: From 1995 to 1997, data sets (351) were collected from 30 fields in central and southern Minnesota to determine the most efficient, fixed-precision, sequential sampling plan for density estimation of aster leafhopper, Macrosteles quadrilineatus Forbes in carrot, Daucus carota (L.). Conventional and organic farms were sampled to obtain a range of leafhopper densities likely to be encountered with various management practices. Densities ranged from 0.01 to 6.97 leafhoppers per sweep. Taylor's a and b parameters were estimated from 266 data sets and used in conjunction with 15 independent data sets to validate the sampling plan with resampling software. The results showed that, for a density range of 0.01-1.61 leafhoppers per sweep, 20 samples of 10 sweeps each must be taken to achieve an average precision level of 0.25 (SE/mean). In subsequent analyses, results were partitioned into low (<0.17 leafhoppers per sweep) and high (> 0.17 leafhoppers per sweep) density data sets. Further analysis, using modified precision levels, showed that either 86 samples of 10 sweeps each (low densities) or 5 samples of 10 sweeps each (high densities) were needed to achieve the desired average precision level of 0.25. Implementation of this plan requires growers to collect a minimum of 5 samples of 10 sweeps each; if the mean density >0.17, then mean actual precision ~0.25, and no further sampling is necessary. For densities <0.17, an additional 5 samples of 10 sweeps each should be taken, and final density estimated (precision may be >0.25). Final density can be compared with the aster yellows index for control guidelines.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Eric C. Burkness, William (Bill) D. Hutchison

Research topic(s) for pests/diseases/weeds:
damage/losses/economics
surveys/sampling/distribution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Macrosteles quadrilineatus	Carrot (Daucus carota)	U.S.A. (mid N)