Hostname: page-component-78c5997874-m6dg7 Total loading time: 0 Render date: 2024-11-15T01:35:25.619Z Has data issue: false hasContentIssue false
  • English
  • Français

Preharvest sampling plan for larvae of the wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae), in winter wheat fields

Published online by Cambridge University Press:  02 April 2012

Christian Nansen ,
Mark E. Payton ,
Justin B. Runyon ,
David K. Weaver ,
Wendell L. Morrill  and
Sharlene E. Sing
Christian Nansen*
Affiliation:
Montana State University, Department of Entomology, 333 Leon Johnson Hall, P.O. Box 173020, Bozeman, Montana 59717, United States of America
Mark E. Payton
Affiliation:
Oklahoma State University, Department of Statistics, 301 Math Sciences, Stillwater, Oklahoma 74078-1056, United States of America
Justin B. Runyon
Affiliation:
Montana State University, Department of Entomology, 333 Leon Johnson Hall, P.O. Box 173020, Bozeman, Montana 59717, United States of America
David K. Weaver
Affiliation:
Montana State University, Department of Entomology, 333 Leon Johnson Hall, P.O. Box 173020, Bozeman, Montana 59717, United States of America
Wendell L. Morrill
Affiliation:
Montana State University, Department of Entomology, 333 Leon Johnson Hall, P.O. Box 173020, Bozeman, Montana 59717, United States of America
Sharlene E. Sing
Affiliation:
Montana State University, Department of Land Resources and Environmental Sciences, 334 Leon Johnson Hall, P.O. Box 173120, Bozeman, Montana 59717, United States of America
*
1 Corresponding author (e-mail: weaver@montana.edu).
Get access Rights & Permissions [Opens in a new window]

Abstract

The wheat stem sawfly, Cephus cinctus Norton, is the most important insect pest of dryland wheat, reducing both harvest efficiency and head weight. When wheat lodged (flattened) by C. cinctus is straight-cut, harvest efficiency is affected in three ways: (1) lodged stems are difficult to collect with the combine, so mature wheat is lost; (2) the combine has to operate more slowly to collect as many of the lodged stems as possible; and (3) there is increased risk of damage to the combine due to lowering of the combine header to recover lodged stems. An alternative harvest method is to swath the wheat before lodging occurs and place it in windrows prior to combining. When swathing is used, harvest efficiency is not affected by the C. cinctus infestation level; however, this type of harvesting is more expensive and labor-intensive than straight- cutting. Thus, swathing should be used only when the crop is heavily infested by C. cinctus, while straight-cutting should be used when the level of C. cinctus infestation is lower. Adapting harvesting practices to the C. cinctus infestation level requires a sampling plan that can reliably and cost-effectively predict the infestation level in a given field. In this study, we (i) evaluate the relationship between sampling effort along field edges and precision of the estimated average infestation level in 6 wheat fields, and (ii) generate a Gaussian regression analysis of the infestation level up to 200 m into 18 wheat fields using two variables, distance from the edge and average infestation level at the edge, as explanatory variables. We conclude that little additional precision for estimates of infestation level is gained by collecting more than 10 samples along field edges. We also conclude that the average C. cinctus infestation level along field edges can be used successfully to predict infestation levels up to 200 m into winter wheat fields. The proposed sampling should be implemented about one month before harvest to provide growers with enough time to make logistical preparations for harvest.

Résumé

Le cèphe du blé, Cephus cinctus Norton, est le ravageur principal du blé des régions arides et il cause à la fois une réduction de la masse des épis et de l'efficacité de la récolte. L'efficacité de la récolte en coupe directe du blé couché par C. cinctus est affectée de trois façons: (1) il y a une perte de blé mûr parce que la moissonneuse-batteuse a du mal à récolter les tiges couchées, (2) la moissonneuse-batteuse doit avancer plus lentement de manière à récolter le plus grand nombre de tiges couchées possible et (3) il y a un risque accru d'endommagement de la barre de coupe qui est surbaissée pour récupérer les tiges couchées. Une méthode de rechange de récolte consiste à faire l'andainage du blé avant que les tiges ne soient couchées et de le placer en andains avant de le moisonner. L'efficacité de la récolte par andainage n'est pas affectée par le niveau d'infestation par C. cinctus, mais ce type de récolte est plus coûteux et requiert plus de main-d'oeuvre que la coupe directe. On doit donc utiliser l'andainage seulement lorsque la récolte est fortement infestée par C. cinctus et faire la coupe directe lorsque le niveau d'infestation par C. cinctus est plus faible. Afin d'adapter les pratiques de récolte au niveau d'infestation de C. cinctus, il faut un plan d'échantillonnage qui puisse prédire de façon fiable et à un coût rentable le niveau d'infestation dans un champ donné. Dans notre étude, (i) nous évaluons dans 6 champs de blé la relation entre l'effort d'échantillonnage en bordure du champ et la précision des niveaux moyens d'infestation estimés et (ii) nous mettons au point dans 18 champs de blé une analyse de régression gaussienne du niveau d'infestation jusqu'à 200 m vers l'intérieur en utilisant deux variables explicatives, la distance depuis le bord et le niveau moyen d'infestation en bordure. Nous concluons que la récolte de plus de 10 échantillons en bordure du champ ajoute peu de précision aux estimations du niveau d'infestation. De plus, le niveau moyen d'infestation par C. cinctus en bordure du champ peut servir à prédire avec succès le niveau d'infestation jusqu'à 200 m à l'intérieur du champ. On doit utiliser le plan d'échantillonnage proposé environ un mois avant la moisson afin que les agriculteurs puissent avoir le temps de faire les ajustements logistiques requis de leur matériel de récolte.

[Traduit par la Rédaction]

Type
Articles
Information
The Canadian Entomologist , Volume 137 , Issue 5 , October 2005 , pp. 602 - 614
Copyright
Copyright © Entomological Society of Canada 2005

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ainslie, C.N. 1920. The western grass-stem sawfly. US Department of Agriculture Bulletin 841. US Government Printing Office, Washington, District of Columbia.Google Scholar
Criddle, N. 1917. Further observations upon the habits of the western wheat-stem sawfly in Manitoba and Saskatchewan. Agricultural Gazette of Canada, 4: 176–177.Google Scholar
Filipy, F.L., Burbutis, P.P., and Fuester, R.W. 1985. Sampling for the European wheat stem sawfly (Hymenoptera: Cephidae). Journal of Economic Entomology, 78: 493–496.Google Scholar
Holmes, N.D. 1982. Population dynamics of the wheat stem sawfly, Cephus cinctus (Hymenoptera: Cephidae), in wheat. The Canadian Entomologist, 114: 775–788.Google Scholar
Holmes, N.D., and Peterson, L.K. 1961. Resistance of spring wheats to the wheat stem sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae). I. Resistance to the egg. The Canadian Entomologist, 93: 250–260.CrossRefGoogle Scholar
Holmes, N.D., and Peterson, L.K. 1962. Resistance of spring wheats to the wheat stem sawfly, Cephus cinctus Nort. (Hymenoptera: Cephidae). II. Resistance to the larva. The Canadian Entomologist, 94: 348–365.CrossRefGoogle Scholar
Ivie, M.A. 2001. On the geographic origin of the wheat stem sawfly Cephus cinctus (Hymenoptera: Cephidae): a new hypothesis of introduction from northeastern Asia. American Entomologist, 47: 84–97.Google Scholar
Morrill, W.L. 1997. The wheat stem sawfly, Cephus cinctus Norton (Hymenoptera: Cephidae), and associated parasitoids in the northern Great Plains of North America. Trends in Entomology, 1: 171–174.Google Scholar
Morrill, W.L., and Kushnak, G.D. 1999. Planting date influence on the wheat stem sawfly (Hymenoptera: Cephidae) in spring wheat. Journal of Agricultural and Urban Entomology, 16: 123–128.Google Scholar
Morrill, W.L., Gabor, J.W., Hockett, E.A., and Kushnak, D.G. 1992 a. Wheat stem sawfly (Hymenoptera: Cephidae) resistance in winter wheat. Journal of Economic Entomology, 85: 2008–2011.Google Scholar
Morrill, W.L., Gabor, J.W., Hockett, E.A., and Kushnak, D.G. 1992 b. Wheat stem sawfly (Hymenoptera: Cephidae): damage and detection. Journal of Economic Entomology, 85: 2413–2417.CrossRefGoogle Scholar
Morrill, W.L., Kushnak, G.D., Bruckner, P.L., and Gabor, J.W. 1994. Wheat stem sawfly (Hymenoptera: Cephidae) damage, rates of parasitism, and overwinter survival in resistant wheat lines. Journal of Economic Entomology, 87: 1373–1376.CrossRefGoogle Scholar
Morrill, W.L., Kushnak, G.D., and Gabor, J.W. 1998. Parasitism of the wheat stem sawfly (Hyme- noptera: Cephidae) in Montana. Biological Control, 12: 159–163.CrossRefGoogle Scholar
Morrill, W.L., Weaver, D.K., and Johnson, G.D. 2000. Trap strip and field border modification for management of the wheat stem sawfly (Hymenoptera: Cephidae). Journal of Entomological Science, 36: 34–45.CrossRefGoogle Scholar
Morrill, W.L., Weaver, D.K., and Johnson, G.D. 2001. Trap strip and field border modification for management of the wheat stem sawfly (Hymenoptera: Cephidae). Journal of Entomological Science, 36: 34–45.CrossRefGoogle Scholar
Nansen, C., Weaver, D.K., Sing, S.E., Runyon, J.B., Morrill, W.L., Grieshop, M.J. et al. 2005 a. Within-field spatial distribution of immature Cephus cinctus (Hymenoptera: Cephidae) in Montana wheat fields. The Canadian Entomologist, 137: 202–214.CrossRefGoogle Scholar
Nansen, C., Macedo, T.B., Weaver, D.K., and Peterson, R.D.K. 2005 b. Spatiotemporal distributions of wheat stem sawfly eggs and larvae in dryland wheat fields. The Canadian Entomologist, 137: 428–440.CrossRefGoogle Scholar
Pesho, G.R., Mcguire, J.U., and McWilliams, J.M. 1971. Sampling methods for surveys of damage caused by the wheat stem sawfly. FAO Plant Protection Bulletin, 19: 122–130.Google Scholar
Runyon, J.B. 2001. Wheat stem sawfly parasitism in varying field sizes and tillage systems in dryland wheat in Montana. M.Sc. thesis, Department of Entomology, Montana State University, Bozeman, Montana.Google Scholar
Runyon, J.B., Morrill, W.L., Weaver, D.K., and Miller, P.R. 2002. Parasitism of the wheat stem sawfly (Hymenoptera: Cephidae) by Bracon cephi and B. lissogaster (Hymenoptera: Braconidae) in wheat fields bordering tilled and untilled fallow in Montana. Journal of Economic Entomology, 95: 1130–1134.CrossRefGoogle Scholar
Sing, S.E. 2002. Spatial and biotic interactions of the wheat stem sawfly with wild oat and Montana dryland spring wheat. Ph.D. thesis, Land Resources and Environmental Sciences, Montana State University, Bozeman, Montana.Google Scholar