Hostname: page-component-7c8c6479df-ph5wq Total loading time: 0 Render date: 2024-03-29T14:02:47.781Z Has data issue: false hasContentIssue false

SURVIVAL OF PUPAE OF MAMESTRA CONFIGURATA (LEPIDOPTERA: NOCTUIDAE) AND TWO OF ITS PARASITES IN UNTILLED AND TILLED SOIL1

Published online by Cambridge University Press:  31 May 2012

W. J. Turnock
Affiliation:
Research Station, Agriculture Canada, Winnipeg, Manitoba R3T 2M9
R.J. Bilodeau
Affiliation:
Research Station, Agriculture Canada, Winnipeg, Manitoba R3T 2M9

Abstract

The survival of Mamestra configurata Wlk. was determined from autumn and spring samples in 1973/74, 1980/81, and 1981/82 taken from unfilled and tilled portions of 12 fields of canola (Brassica campestris L. and B. napus L.). Survival from the pre-pupal stage in the autumn to post-diapause pupae in the spring varied from 2.9 to 56.5% in unfilled soil and from 0 to 25.4% in tilled soil. In untilled soil, the variations among fields in total mortality of M. configurata were related to parasitism by Banchus flavescens and to overwintering mortality. In tilled soil, overwintering mortality accounted for most of the variability in total mortality among fields. The percentage of mortality from injury to pupae, and their disappearance following tillage, greatly increased but this type of mortality did not account for much of the variability in total mortality. The disappearance of pupae following tillage was attributed to predation. In both untilled and tilled soils, the amount of overwintering mortality was related to the depth of accumulated snow, and mortality was lower in untilled soil because the stubble trapped more snow. The survival of M. configurata was not related to soil type, the type of tillage equipment, or the frequency of tillage. The number of adults emerging from untilled and tilled soil in one field were 2.58 and 0.27/m2 for M. configurata, 5.22 and 2.85/m2 for the parasite B. flavescens, and 4.46 and 3.60/m2 for the parasite Athrycia cinerea, indicating that the survival of the parasites was less affected by tillage than that of their host.

Tillage may reduce the frequency and severity of outbreaks of M. configurata not only by increasing mortality but also by differentially affecting the survival of its main parasites.

Résumé

On a déterminé la survie de Mamestra configurata Wlk. à partir d'échantillons prélevés à l'automne et au printemps de 1973–1974, 1980–1981 et 1981–1982 de certaines parties travaillées et non travaillée de 12 champs de Canola (Brassica campestris L. et B. napus L.). La survie du stade prépupal à l'automne au stade pupe de post-diapause au printemps varie de 2.9 à 56% en sol non travaillé et de 0 à 25.4% en sol travaillé. Dans le premier cas, les variations de mortalité totale de M. configurata entre les champs sont reliées au parasitisme par Banchus flavescens et à la mortalité d'hivernage. Dans le second cas, la mortalité d'hivernage représente le gros des variations de la mortalité totale entre les champs. Le pourcentage de mortalité de la ponte au stade pupe et la disparition des pupes après travail du sol augmentent considérablement, mais ce type de mortalité n'influe pas beaucoup sur la variabilité de la mortalité totale. La disparition des pupes après travail est attribuée à la prédation. Dans les deux genres de sols, l'importance de la mortalité d'hivernage est reliée à la profondeur de la couverture de neige et la mortalité est plus faible en sol non travaillé puisque le chaume de culture emprisonne plus de neige. La survie de M. configurata n'a aucun rapport avec le type de sol, le genre de machines agricoles, ni la fréquence du travail. Le nombre d'adultes émergeant des parties travaillées et non travaillées d'un champ sont de 2.58 et 0.27/m2 pour M. configurata, 5.22 et 2.85/m2 pour le parasite B. flavescens et 4.46 et 3.60/m2 pour le parasite Athrycia cinerea, ce qui donne à penser que le travail du sol influe moins sur la survie des parasites que sur celle de leur hôte.

Le travail peut réduire la fréquence et la gravité d'infestations de M. configurata, non seulement en accentuant la mortalité, mais aussi en modifiant différemment la survie de ses principaux parasites.

Type
Articles
Copyright
Copyright © Entomological Society of Canada 1984

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

Hegdekar, B. M. 1977. Photoperiodic and temperature regulation of diapause induction in the bertha armyworm, Mamestra configurata Walker. Manitoba Ent. 11: 5660.Google Scholar
Ives, W. G. H., Turnock, W. J., Buckner, C. H., a, and Muldrew, J. A.. 1968. Larch sawfly population dynamics: techniques. Manitoba Ent. 2: 536.Google Scholar
Southwood, T. R. E. 1978. Ecological Methods with Particular Reference to the Study of Insect Populations. A Halstead Press Book. 2nd ed.Google Scholar
Turnock, W. J. and Philip, H. G.. 1977. The outbreaks of bertha armyworm, Mamestra configurata (Noctuidae: Lepidoptera), in Alberta, 1971 to 1975. Manitoba Ent. 11: 1021.Google Scholar
Turnock, W. J., Lamb, R. J., and Bodnaryk, R. P.. 1983. Effects of cold stress during pupal diapause on the survival and development of Mamestra configurata (Lepidoptera: Noctuidae). Oecologia 56: 185192.CrossRefGoogle ScholarPubMed
Wylie, H. G. and Bucher, G. E.. 1977. The bertha armyworm, Mamestra configurata (Lepidoptera: Noctuidae). Mortality of immature stages on the rape crop, 1972–1975. Can. Ent. 109: 823837.CrossRefGoogle Scholar