The trapping frequency was strongly influenced by the trapping period and increased with the increase of insect densities. The normal and Poisson model could not be used to describe the distribution of the count frequency of the adults in the samples, while the negative binomial model could describe this distribution in 18 out of 27 sampling sets at ≤ 1.0 A/kg. The adults had an aggregation distribution at any temperature, moisture content and adult density. There was an autocorrelation of insect densities at adjacent locations at ≥ 1.0 A/kg, while no autocorrelation in the vertical direction. In each layer, adults preferred the center location at 0.5 A/kg, while this trend was unidentified at other densities. The recovered adults in the top layer were less than that in the middle layer, while no significant difference between at middle and bottom layers. The insect number in each sample was counted. The trapped adults were counted daily up to 7 d, and then 15 kg wheat was sampled at each trap location. In each layer, five traps were installed at the center and half radii of the bin individually. Inside each bin, 15 probe traps were vertically installed in three layers. The introduced adult densities were 0.5, 1.0, and 2.0 adults/kg wheat (A/kg). Movement and distribution of Sitophilus zeamais adults and relationship between their trapping frequency and insect density were determined in one tonne wheat with 11.5 ± 0.2, 12.5 ± 0.1 and 13.5 ± 0.2% moisture contents (wet basis) inside cylindrical bins at 20, 25 and 30 ☌. This is the first paper illustrating the development and evaluation of sequential sampling plans for a stored-product insect. The performance of these sampling plans was evaluated (validated) using independent data sets and an IBM-PC software program specifically designed to test the plans. ferrugineus infestation level relative to an action threshold. The presence/absence data were used to develop a sampling plan for classifying the C. ferrugineus with a fixed level of precision. Insect count data were used to develop a sampling plan for estimating the density of C. For adults of the rusty grain beetle, Cryptolestes ferrugineus (Stephens), we developed sequential sampling plans based on complete counts and the presence/absence of insects in 0.5 kg grain samples removed with a trier from the top 1 m of wheat stored in farm bins. Sequential sampling plans, which are based on a variable sample size, are generally more cost effective than plans based on a fixed sample size. The development and evaluation of appropriate sampling plans are needed for cost-effective management of stored-product insects.
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