Hostname: page-component-78c5997874-mlc7c Total loading time: 0 Render date: 2024-11-18T18:49:50.834Z Has data issue: false hasContentIssue false
  • English
  • Français

EFFECT OF TEMPERATURE AND EXPOSURE TIME ON TOXICITY OF BACILLUS THURINGIENSIS BERLINER SPRAY DEPOSITS TO SPRUCE BUDWORM, CHORISTONEURA FUMIFERANA CLEMENS (LEPIDOPTERA: TORTRICIDAE)

Published online by Cambridge University Press:  31 May 2012

Kees van Frankenhuyzen
Kees van Frankenhuyzen
Affiliation:
Forestry Canada, Forest Pest Management Institute, PO Box 490, Sault Ste. Marie, Ontario, Canada P6A 5M7
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Experiments were conducted using balsam fir twigs treated with Bacillus thuringiensis Berliner to examine the influence of temperature and exposure time on mortality of spruce budworm, Choristoneura fumiferana Clemens. Twigs were sprayed with a commercial formulation (8.4 BIU/L) using droplets of 40–70 μm diameter at densities, ranging from 0.5 to 5.5 droplets per needle. Temperature affected progression but not the level of cumulative mortality during 14 days of feeding on sprayed foliage. The LT50 decreased from 12–17 days at 13°C to 2–4 days at 25°C, depending on droplet density. Temperature between 13 and 25°C had a limited effect on dose acquisition because 40–60% of the larvae were able to acquire a lethal dose within 1 day of feeding on foliage with 0.5–1.5 droplets per needle, regardless of temperature. Under these conditions dose acquisition was not limited by temperature-dependent consumption of foliage, but rather by feeding inhibition associated with the dose initially ingested. This also limited the influence of exposure time; a 7- or 14-fold increase in exposure time increased larval mortality at most by 25%. Implications of these findings for improving efficacy of B. thuringiensis in forestry applications are discussed.

Résumé

Des expériences ont été menées utilisant des branches de sapin baumier traitées avec Bacillus thuringiensis Berliner afin d’étudier l’influence de la température et du temps d’exposition sur la mortalité de la tordeuse des bourgeons de l’épinette, Choristoneura fumiferana Clemens. Les branches ont été arrosées d’une formule commerciale (8,4 BIU/L) utilisant des gouttelettes de 40–70 μm de diamètre à des densités variant entre 0,5 et 5,5 gouttelettes par aiguille. Pendant 14 jours de nutrition sur du feuillage traité, la température a affecté la progression de la mortalité mais pas son niveau cumulatif. Le TL50 est passé de 12–17 jours à 13°C, à 2–4 jours à 25°C, dépendant de la densité des gouttelettes. La température entre 13 et 25°C n’a eu qu’un effet limité sur l’acquisition de dose puisque 40–60% des larves ont été capables d’ingérer une dose léthale à l’intérieur d’une journée de nutrition sur du feuillage avec 0.5–1.5 gouttelettes par aiguille, quelque soit la température. Sous ces conditions, l’acquisition de dose n’a pas été limitée par un niveau de consommation du feuillage dépendant de la température, mais plutôt par l’inhibition de la nutrition associée à la dose initiallement ingérée. Ceci a aussi limité l’influence du temps d’exposition; une augmentation du temps d’exposition par un facteur de 7 à 14 n’a augmenté la mortalité larvaire qu’au plus de 25%. Les implications de ces résultats pour l’amélioration de l’efficacité de B. thuringiensis en foresterie sont discutées.

Type
Articles
Information
The Canadian Entomologist , Volume 122 , Issue 1 , February 1990 , pp. 69 - 75
Copyright
Copyright © Entomological Society of Canada 1990

References

Beckwith, R.C., and Stelzer, M.J.. 1987. Persistence of Bacillus thuringiensis in two formulations applied by helicopter against the western spruce budworm (Lepidoptera: Tortricidae) in North Central Oregon. J. econ. Ent. 80: 204–207.CrossRefGoogle Scholar
Carrow, J.R. 1983. B.t. and the spruce budworm—1983. New Brunswick Department of Natural Resources, Fredericton, N.B.91 pp.Google Scholar
Carter, N.E. 1988. Protection spraying against spruce budworm in New Brunswick, 1988. New Brunswick Department of Natural Resources and Energy NRE/RNE-89-02-001, Fredericton, N.B.20 pp.Google Scholar
Eidt, D.C. 1987. Biological interface—insecticides, insects, and post-spray weather. pp. 215–218in Green, G.W. (Ed.), Proceedings of Symposium on the Aerial Application of Pesticides in Forestry. Associate Committee on Agriculture and Forestry Aviation, National Research Council, AFA-TN-18, Ottawa, Ont.Google Scholar
Fast, P.G., Kettela, E.G., and Wiesner, C.J.. 1985. Measurement of foliar deposits of B.t. and their relation to efficacy. pp. 148–149in Grimble, D.G., and Lewis, F.B. (Eds.), Proceedings of a Symposium: Microbial Control of Spruce Budworms and Gypsy Moths, April 10–12 1984, Windsor Locks, Conn. GTR-NE-100, USDA, Broomall, PA.Google Scholar
Fast, P.G., and Régnière, J.. 1984. Effect of exposure time to Bacillus thuringiensis on mortality and recovery of the spruce budworm (Lepidoptera: Tortricidae). Can. Ent. 116: 123–130.CrossRefGoogle Scholar
Finney, D.J. 1971. Probit Analysis. Cambridge University Press.Google Scholar
Grisdale, D. 1970. An improved method for rearing large numbers of spruce budworm, Choristoneura fumiferana (Lepidoptera: Tortricidae). Can. Ent. 102: 1111–1117.CrossRefGoogle Scholar
Morris, O.N., Cunningham, J.C., Finney-Crawley, J.R., Jaques, R.P., and Kinoshita, G.. 1986. Microbial insecticides in Canada: their registration and use in agriculture, forestry and public and animal health. A report prepared by the Special Committee of the Science Policy Committee, Entomological Society of Canada. Suppl. Bull. Ent. Soc. Can. 18. 43 pp.Google Scholar
Nealis, V.G., and Fraser, S.. 1988. Rate of development, reproduction, and mass-rearing of Apanteles fumiferanae Vier. (Hymenoptera: Braconidae) under controlled conditions. Can. Ent. 120: 197–204.CrossRefGoogle Scholar
Retnakaran, A. 1983. Spectrophotometric determination of larval ingestion rates in the spruce budworm (Lepidoptera: Tortricidae). Can. Ent. 115: 31–40.CrossRefGoogle Scholar
Stelzer, M.J., and Beckwith, R.C.. 1988. Comparison of two isolates of Bacillus thuringiensis in a field test on western spruce budworm (Lepidoptera: Tortricidae). J. econ. Ent. 81: 880–886.CrossRefGoogle Scholar
Sundaram, K.M., and Sundaram, A.. 1987. Influence of formulation on spray deposit patterns, dislodgeable and penetrated residues and persistence characteristics of fenitrothion in conifer needles. Pestic. Sci. 18: 259–271.CrossRefGoogle Scholar
van Frankenhuyzen, K., and Nystrom, C.W.. 1987. Effect of temperature on mortality and recovery of spruce budworm (Lepidoptera: Tortricidae) exposed to Bacillus thuringiensis Berliner. Can. Ent. 119: 941–954.CrossRefGoogle Scholar
van Frankenhuyzen, K., and Nystrom, C.W.. 1989. Residual toxicity of a high-potency formulation of Bacillus thuringiensis to spruce budworm (Lepidoptera: Tortricidae). J. econ. Ent. 82: 868–872.CrossRefGoogle Scholar
West, R.J., Raske, A.C., Retnakaran, A., and Lim, K.P.. 1987. Efficacy of various Bacillus thuringiensis Berliner var. kurstaki formulations and dosages in the field against the hemlock looper, Lambdina fiscellaria fiscellaria (Guen.) (Lepidoptera: Geometridae) in Newfoundland. Can. Ent. 119: 449–458.CrossRefGoogle Scholar