Repeated sampling of rural maize stores in Benin was conducted toevaluate published parameters of a sequential sampling plan for anegative binomial distribution to determine pest status forProstephanus truncatus (Horn) and Sitophiluszeamais Motschulsky. A computer program was used to rerandomizethe data and evaluate the effects, in terms of average sample numberand error rates, of different sampling plan parameter values. Withrespect to P. truncatus, lower and upper thresholds of 0.2and 1.0 insects per ear and parameter values of k = 0.2and α = β = 0.1 were found to be adequate. With respectto S. zeamais, lower and upper thresholds of 10 and 20insects per ear and parameter values of k = 1.0 andα = β = 0.1 were found to be adequate. Simplifiedsampling rules were proposed in which 11 ears should be sampled and ifno P. truncatus are found, the population is low; otherwisethe Wald plan should be followed. Owing to the lower per capita rate ofdamage, effective simplified sampling rules for S. zeamaiswere difficult to construct. An evaluation of the visual assessmentscale using whole ears showed that a visual scale estimating percentagedamage rather than percentage loss, might be easy to construct andpreferable for traders. Further work is needed to improve theusefulness of the visual scale in pest management decision support.
You have requested a machine translation of selected content from our databases. This functionality is provided solely for your convenience and is in no way intended to replace human translation. Neither BioOne nor the owners and publishers of the content make, and they explicitly disclaim, any express or implied representations or warranties of any kind, including, without limitation, representations and warranties as to the functionality of the translation feature or the accuracy or completeness of the translations.
Translations are not retained in our system. Your use of this feature and the translations is subject to all use restrictions contained in the Terms and Conditions of Use of the BioOne website.
Vol. 93 • No. 6