Development and validation of sequential sampling plans for Sitophilus species associated with pet specialty stores.

Abstract

Eight pet stores in Kansas, USA were sampled between February and August 2002, using traps baited with food and pheromone lures for capturing multiple species of beetle adults. Thirty traps were arranged in a grid pattern in each store and were checked every 2-3 weeks. The most common and abundant beetles captured in traps in all eight stores were the Sitophilus spp. (rice, granary and maize weevils). The rice weevil, Sitophilus oryzae, was the most common and predominant of the three weevils. Trap capture data from each store were used to calculate mean numbers of Sitophilus spp. trapped per week and associated variance and weekly presence or absence of adults. About 60% of the weekly trap capture data from the 8 stores were used for developing fixed precision and binomial sequential sampling plans and the other 40% of the data were used for testing the performance of these plans through computer simulations using the "Resampling for Validation of Sampling Plans" software. Green's fixed precision sampling plan was used for estimating Sitophilus spp. density of 0.62 insects trapped per week that corresponded with 50% of infested traps. The actual precision and sample sizes needed for estimating density at the fixed precision levels of 0.25, 0.35 and 0.50 were determined. Wald's sequential probability ratio test plan and a fixed sample size binomial plan were developed to classify infestation level with respect to an infestation threshold (50% of infested traps). Operating characteristic and average sample number curves generated using the validation data sets were used to gauge performance of the binomial plan. In addition, the actual errors in classifying infestation levels were also determined. The development, performance and utility of these sampling plans in retail stores are discussed.

A Binomial and Species-Independent Approach to Trap Capture Analysis of Flying Insects

“…These varying results indicate that the Iwao method may be a better approach than the SPRT, but it seems to be quite sensitive to the stop line parameters and estimates of the TPL parameters. Regarding stored grain insects, sequential sampling plans have been developed for direct sampling, for example insects per maize, Zea mays L., ear or volume of grain (Subramanyam et al 1997, Meikle et al 2000, Toews et al 2002, but few studies have been published on the development of sequential sampling plans for trapping data of ßying insects in stored product environments. Carvalho et al (2006) trapped cigarette beetles, Lasioderma serricorne (F.) (Coleoptera: Anobiidae) at 26 pheromone-baited locations.…”

Monitoring Tribolium castaneum (Herbst) in pilot-scale warehouses treated with β-cyfluthrin: are residual insecticides and trapping compatible?

“…Trap capture data are commonly used to document species composition, spatial distributions, temporal population dynamics, emigration and immigration, and pesticide efficacy (Arbogast et al, 2000(Arbogast et al, , 2002Roesli et al, 2003b;Campbell & Arbogast, 2004;Toews et al, 2006a;Trematerra et al, 2007). Larger datasets have been used to develop and validate sampling plans for use in grain storages, retail stores and factories (Subramanyam & Harein, 1990;Subramanyam et al, 1997;Athanassiou & Buchelos, 2001;Toews et al, 2002;Carvalho et al, 2006).…”

Modern Stored-Product Insect Pest Management

“…For pet food at retail stores, Sitophilus spp. have been shown to be a problem (Toews et al 2003). Inspection and pheromone-baited sticky traps are the primary methods of monitoring for insect pests in retail stores.…”

“…pet store 0.62 insects/trap/week Toews et al 2003 Sitophilus zeamais Motschulsky maize trader 5-6% damage Compton et al 1998 Sitophilus spp. and R. dominica that cause more damage than Tribolium spp.…”