Skip to main content Accessibility help
×
Home

SEQUENTIAL SAMPLING OF ADULT NORTHERN AND WESTERN CORN ROOTWORMS (COLEOPTERA: CHRYSOMELIDAE) IN SOUTHERN ONTARIO

  • H.J. McAuslane (a1), C.R. Ellis (a1) and O.B. Allen (a2)

Abstract

Three sequential-sampling plans were developed for adult Diabrotica barberi Smith and Lawrence and D. virgifera virgifera LeConte in field corn in southern Ontario. The distribution of both species was well approximated by the negative binomial distribution and obeyed Taylor’s power law. Two plans, following the methods of Kuno (1969) and Green (1970), estimated populations with predetermined precision. The third plan, based on Wald’s (1947) sequential probability ratio test, categorized populations relative to an economic threshold. Different sequential-sampling plans were constructed for 1st-year fields and for all other fields because the parameter k, measuring the extent of aggregation of the beetles, differed between these two classes of fields. Decision equations for Wald’s plan in 1st-year fields were: D1 = 0.98n − 17.75 and D2 = 0.98n + 13.82. Decision equations for 2nd-year or older fields were: D1 = 0.99n − 13.42 and D2 = 0.99n + 10.45. The use of Wald’s plan reduced the required sample size by 55% in 1st-year fields, and by 48% in all other fields. The savings associated with the other sequential-sampling plans were not significant.

Trois plans d’échantillonnage séquentiel ont été développés pour estimer les populations adultes de Diabrotica barberi Smith et Lawrence et D. virgifera virgifera LeConte, retrouvées dans le maïs fourrage du sud de l’Ontario. La distribution négative binomiale a bien approximé les distributions de ces deux espèces. Ces deux distributions obéissaient aussi à la loi de puissance de Taylor. Deux plans, suivant les méthodes de Kuno (1969) et de Green (1970), estimaient les populations avec des niveaux de précision pré-determinées. Le troisième plan, basé sur Wald (1947), catégorisait les populations relativement au seuil économique. Des plans différents ont été développé pour les champs de 1 an et pour les autres champs plus âgés parce que le paramètre k, qui mesure l’aggrégation des coléoptères, différait entre ces deux catégories de champs. Les équations de décision du plan de Wald pour les champs de 1 an étaient:D1 = 0,98n − 17,75 et D2 = 0,98n + 13,82. Les équations pour les champs plus âgés étaient:D1 = 0,99n − 13,42 et D2 = 0,99n + 10,45. L’usage du plan de Wald a réduit le nombre d’échantillons requis de 55% pour les champs de 1 an, et de 48% pour les autres champs. Les épargnes associées avec les deux autres plans d’échantillonnage séquentiel n’étaient pas significatives.

Copyright

References

Hide All
Anonymous. 1985. Field Crop Recommendations. Ont. Min. Agric. Food Publ. 296.
Bliss, C.I., and Owen, A.R.G.. 1958. Negative binomial distributions with a common k. Biometrika 45: 3758.
Fisher, J.R. 1985. Comparison of controlled infestations of Diabrotica virgifera virgifera and Diabrotica barberi (Coleoptera: Chrysomelidae) on corn. J. econ. Ent. 78: 14061408.
Foster, R.E., Tollefson, J.J., and Steffey, K.L.. 1982. Sequential sampling plans for adult corn rootworms (Coleoptera: Chrysomelidae). J. econ. Ent. 75: 791793.
Green, R.H. 1970. On fixed precision level sequential sampling. Res. Popul. Ecol. (Kyoto) 12: 249251.
Iwao, S. 1975. A new method of sequential sampling to classify populations relative to a critical density. Res. Popul. Ecol. (Kyoto) 16: 281288.
Iwao, S., and Kuno, E.. 1968. Use of the regression of mean crowding on mean density for estimating sample size and the transformation of data for the analysis of variance. Res. Popul. Ecol. (Kyoto) 10: 210214.
Karandinos, M.G. 1976. Optimum sample size and comments on some published formulae. Bull. ent. Soc. Am. 22: 417421.
Kuno, E. 1969. A new method of sequential sampling to obtain the population estimates with a fixed level of precision. Res. Popul. Ecol. (Kyoto) 11: 127136.
Sawyer, A.J. 1985. Efficient monitoring of the density of adult northern corn rootworm (Coleoptera: Chrysomelidae) in field corn. Can. Ent. 117: 171183.
Stamm, D.E., Mayo, ZB, Campbell, J.B., Witkowski, J.F., Andersen, L.W., and Kozub, R.. 1985. Western corn rootworm (Coleoptera: Chrysomelidae) beetle counts as a means of making larval control recommendations in Nebraska. J. econ. Ent. 78: 794798.
Steffey, K.L., and Tollefson, J.J.. 1982. Spatial dispersion patterns of northern and western corn rootworm adults in Iowa cornfields. Environ. Ent. 11: 283286.
Taylor, L.R. 1961. Aggregation, variance and the mean. Nature 189: 732735.
Taylor, L.R. 1984. Assessing and interpreting the spatial distributions of insect populations. A. Rev. Ent. 29: 321357.
Taylor, L.R., Woiwod, I.P., and Perry, J.N.. 1978. The density-dependence of spatial behavior and the rarity of randomness. J. anim. Ecol. 47: 383406.
Wald, A. 1947. Sequential analysis. John Wiley and Sons, New York. 212 pp. (Reprinted Dover Publ. Inc., New York, 1973.) (Original reference not seen.)
Waters, W.E. 1955. Sequential sampling in forest insect surveys. For. Sci. 1: 6879.
Willson, L.J., and Folks, J.L.. 1983. Sequential estimation of the mean of the negative binomial distribution. Biometrics 40: 109117.

SEQUENTIAL SAMPLING OF ADULT NORTHERN AND WESTERN CORN ROOTWORMS (COLEOPTERA: CHRYSOMELIDAE) IN SOUTHERN ONTARIO

  • H.J. McAuslane (a1), C.R. Ellis (a1) and O.B. Allen (a2)

Metrics

Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed.