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ARS Home » Pacific West Area » Corvallis, Oregon » Horticultural Crops Research Unit » Research » Publications at this Location » Publication #137959
Title: SAMPLING CONSIDERATIONS FOR GARDEN SYMPHYLANS (SCUTIGERELLA IMMACULATA NEWPORT) IN WESTERN OREGON

Author
item UMBLE, JOHN - OSU
item Fisher, James

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/1/2003
Publication Date: 10/1/2003
Citation: Umble, J.R., Fisher, J.R. 2003. Sampling considerations for garden symphylans (Scutigerella immaculata Newport) in Western Oregon. Journal of Economic Entomology. 2003. v96 p. 969-974.

Interpretive Summary: Recommendations were developed for using a potato bait sampling method to measure garden symphylan populations in western Oregon. The developed sampling recommendations performed well at sample sizes of 30 and greater. One to two times more samples were required for the new bait sampling method than the standard soil sampling method at the same level of accuracy, but the bait samples took much less time than the soil samples. Fewer samples were required in June (36% lower) than in April or May. The bait sampling method provides an efficient reliable alternative to the standard soil sampling method used to monitor garden symphylan populations

Technical Abstract: Sampling recommendations were developed for a potato bait sampling method used to estimate garden symphylan (Scutigerella immaculata Newport) densities in western Oregon. Sample size requirements were developed using Taylor's power law to describe the relationship between sample means and variances. Sampling recommendations developed using the power law performed well at sample sizes of 30 and greater, when validated by resampling a large independent data set. Sample size requirements for the bait sampling method were 1.6 times greater than the requirements for the soil sampling method over densities from 1 to 20 S. immaculata per sample unit. As S. immaculata densities increased from April to May, sample size requirements decreased by 36% for fixed precision levels. For sampling in April, decreasing the damage threshold from 20 to 10 and 5 S. immaculata per sample unit required 1.6 and 2.5 times more sample units respectively for a fixed precision level appropriate for pest management (c = 0.25). The bait sampling method provides an efficient reliable alternative to the standard soil sampling method used to monitor garden symphylan populations.