Hostname: page-component-586b7cd67f-t7fkt Total loading time: 0 Render date: 2024-11-24T17:42:27.277Z Has data issue: false hasContentIssue false
  • English
  • Français

Virulence of the entomopathogenic fungus Lecanicillium (Deuteromycota: Hyphomycetes) to Pissodes strobi (Coleoptera: Curculionidae)

Published online by Cambridge University Press:  02 April 2012

Harry H. Kope ,
René I. Alfaro  and
Robert Lavallée
Harry H. Kope*
Affiliation:
Pacific Forestry Centre, Canadian Forest Service, Victoria, British Columbia, Canada V8Z 1M5
René I. Alfaro
Affiliation:
Pacific Forestry Centre, Canadian Forest Service, Victoria, British Columbia, Canada V8Z 1M5
Robert Lavallée
Affiliation:
Centre de foresterie des Laurentides, Service canadien des forêts, Sainte-Foy, Québec, Canada G1V 4C7
*
1 Corresponding author (e-mail: [email protected]).
Get access Rights & Permissions [Opens in a new window]

Abstract

The widely occurring fungal genus Lecanicillium Zare & W. Gams (formerly Verticillium) includes species that are pathogenic to insects. We collected 27 Lecanicillium isolates from soil and from dead adult Pissodes strobi (Peck) in British Columbia, Canada, and assessed their virulence against this host. Eighteen isolates were identified as L. longisporum (Petch) Zare & W. Gams and six as L. muscarium (Petch) Zare & W. Gams, while three isolates could not be identified to the species level. We assayed a subset of these isolates (14 L. longisporum, 3 L. muscarium, and 1 Lecanicillium sp.) as well as the fungal component of the commercial products Mycotal® (L. muscarium) and Vertalec® (L. longisporum) and a herbarium isolate (Lecanicillium sp.). When adult weevils were inoculated with a conidial suspension (1 × 107 conidia/mL), mycosis-related mortality at the end of a 17-day incubation period varied between 20% and 100%, depending on the isolate tested. Eight of the isolates killed >75% of weevils: a Lecanicillium sp. isolate, PFC19, which displayed the lowest LT50 value; five indigenous L. longisporum isolates; and both commercial products. In a goodness-of-fit test comparing isolate virulence among species, the unidentified PFC19 isolate was found to be more effective than either L. longisporum or L. muscarium, while L. longisporum caused somewhat greater mortality than L. muscarium. In a similar analysis, isolates extracted from soils tended to be more effective than those obtained from cadavers. Horizontal transmission to live P. strobi was observed using different isolates of Lecanicillium species. Notwithstanding the variability in virulence, the indigenous Lecanicillium species that we isolated and assayed are confirmed as pathogenic to P. strobi in British Columbia.

Résumé

Le genre de champignons Lecanicillium Zare & W. Gams (précédemment Verticillium) à large répartition géographique contient des espèces pathogènes pour les insectes. Nous avons recueilli 27 isolats de Lecanicillium dans le sol et sur des cadavres d'adultes de Pissodes strobi (Peck) en Colombie-Britannique, Canada, et nous avons évalué leur virulence vis-à-vis cet hôte. Dix-huit des isolats ont été identifiés comme L. longisporum (Petch) Zare & W. Gams et six comme L. muscarium (Petch) Zare & W. Gams, alors que trois autres n'ont pu être identifiés à l'espèce. Nous avons évalué un sous-ensemble de ces isolats (14 L. longisporum, 3 L. muscarium et 1 Lecanicillium sp.), de même que la composante fongique des produits commerciaux Mycotal® (L. muscarium) et Vertalec® (L. longisporum) et un isolat d'herbier (Lecanicillium sp.). Après une inoculation avec une suspension de conidies (1 × 107 condidies/mL), les charançons adultes subissent après une période d'incubation de 17 jours une mortalité due à la mycose qui varie de 20 % à 100 % selon l'isolat utilisé. Huit des isolats tuent >75 % des charançons, dont un isolat de Lecanicillium sp. (PFC19) qui possède le LT50 le plus bas, cinq isolats indigènes de L. longisporum et les deux produits commerciaux. Un test d'ajustement qui compare la virulence de l'isolat en fonction de l'espèce montre que l'isolat non indentifié PFC19 est plus efficace que L. longisporum et que L. muscarium et que L. longisporum cause un mortalité un peu plus élevée que L. muscarium. Une analyse similaire montre que les isolats extraits des sols ont tendance à être plus efficaces que ceux récoltés sur les cadavres. Nous avons observé une transmission horizontale chez des P. strobi vivants à l'aide de différents isolats de Lecanicillium. Malgré la variabilité de leur virulence, les espèces indigènes de Lecanicillium que nous avons récoltées et évaluées se sont avérées pathogènes pour P. strobi en Colombie-Britannique.

[Traduit par la Rédaction]

Type
Articles
Information
The Canadian Entomologist , Volume 138 , Issue 2 , April 2006 , pp. 253 - 262
Copyright
Copyright © Entomological Society of Canada 2006

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

Abbott, W.S. 1925. A method for computing the effectiveness of an insecticide. Journal of Economic Entomology, 18: 265–267.CrossRefGoogle Scholar
Ahmed, S.I., and Leather, S.R. 1994. Suitability and potential of entomopathogenic microorganisms for forest pest management — some points for consideration. International Journal of Pest Management, 40: 287–292.CrossRefGoogle Scholar
Alfaro, R.I. 1994. The white pine weevil in British Columbia: biology and damage. In The white pine weevil: biology, damage and management. Symposium proceedings, Richmond, British Columbia, 19–21 January 1994. FRDA Report 226. Edited by Alfaro, R.I., Kiss, G., and Fraser, R.G.. Canadian Forest Service, Pacific Forestry Centre, Victoria, British Columbia, and BC Ministry of Forests, Victoria, British Columbia. pp. 7–22.Google Scholar
Alfaro, R.I., Hulme, M.A., and Harris, J.W.E. 1985. Insects associated with the Sitka spruce weevil, Pissodes strobi (Coleoptera: Curculionidae), on Sitka spruce, Picea sitchensis, in British Columbia, Canada. Entomophaga, 32: 415–418.CrossRefGoogle Scholar
Alfaro, R.I., Borden, J.H., Fraser, R.G., and Yanchuk, A. 1995. The white pine weevil in British Columbia: basis for an integrated pest management system. Forestry Chronicle, 71: 66–73.CrossRefGoogle Scholar
Bidochka, M.J., Kasperski, J.E., and Wild, G.A.M. 1998. Occurrence of the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana in soils from temperate and near-northern habitats. Canadian Journal of Botany, 76: 1198–1204.CrossRefGoogle Scholar
Brownbridge, M., Humber, R.A., Parker, B.L., and Skinner, M. 1993. Fungal entomopathogens recovered from Vermont forest soils. Mycologia, 85: 358–361.CrossRefGoogle Scholar
Hajek, A.E. 1997. Ecology of terrestrial fungal entomopathogens. Advances in Microbial Ecology, 15: 193–249.CrossRefGoogle Scholar
Hajek, A.E., and St. Leger, R.J. 1994. Interactions between fungal pathogens and insect hosts. Annual Review of Entomology, 39: 293–322.CrossRefGoogle Scholar
Hall, R.A. 1984. Epizootic potential for aphids of different isolates of the fungus Verticillium lecanii. Entomophaga, 29: 311–321.CrossRefGoogle Scholar
Harney, S., and Widden, P. 1991 a. Physiological properties of the entomopathogenic Hyphomycete Paecilomyces farinosus in relation to its role in the forest system. Canadian Journal of Botany, 69: 1–5.CrossRefGoogle Scholar
Harney, S., and Widden, P. 1991 b. The ecology of Paecilomyces farinosus in two balsam fir forests infested with spruce budworm. Canadian Journal of Botany, 69: 512–515.CrossRefGoogle Scholar
Inglis, D., Goettel, M.S., Butt, T.M., and Strasser, H. 2001. Use of hyphomycetous fungi for managing insect pests. In Fungi as biocontrol agents: progress, problems and potential. Edited by Butt, T.M., Jackson, C., and Magan, N.. CABI Publishing, New York. pp. 23–69.CrossRefGoogle Scholar
Kish, L.P., and Allen, G.E. 1978. The biology and ecology of Nomuraea rileyi and a program for predicting its incidence on Anticarsia gemmatalis in soybean. Florida Agricultural Experiment Station Bulletin 795. University of Florida, Gainesville, Florida.Google Scholar
Kope, H.H., Peterson, M., and Alfaro, R. 2000. Pathogenicity of Verticillium lecanii to Pissodes strobi. Canadian Journal of Plant Pathology, 22: 187. [Abstr.]CrossRefGoogle Scholar
Minitab Inc. 2003. MINITAB®, release 14.0 for Windows [computer program]. Minitab Inc., State College, Pennsylvania. Available from http://www.minitab.com.Google Scholar
Robertson, J.L., and Preisler, H.K. 1992. Pesticide bioassays with arthropods. CRC Press, Boca Raton, Florida.Google Scholar
Silver, G.T. 1968. Studies on the Sitka spruce weevil, Pissodes sitchensis, in British Columbia. The Canadian Entomologist, 100: 93–110.CrossRefGoogle Scholar
Sokal, R.R., and Rohlf, R. 1995. Biometry: the principles and practices of statistics in biological research. 3rd ed. W.H. Freeman and Company, New York.Google Scholar
Throne, J.E., Weaver, D.K., Chew, V., and Baker, J.E. 1995. Probit analysis of correlated data: multiple observations over time at one concentration. Journal of Economic Entomology, 88: 1510–1512.CrossRefGoogle Scholar
Timonin, M., and Morris, O.N. 1974. Pathogenicity of some entomogenous fungi; their compatibility and integrated activity with chemical insecticides against P. strobi Peck. Environment Canada, Canadian Forest Service, Chemical Control Research Institute, Ottawa, Ontario. CC-X-69.Google Scholar
Vänninen, I. 1995. Distribution and occurrence of four entomopathogenic fungi in Finland: effect of geographical location, habitat type and soil type, Mycological Research, 100: 93–101.Google Scholar
Widden, P. 1979. Fungal populations from forest soils in southern Quebec. Canadian Journal of Botany, 57: 1324–1331.CrossRefGoogle Scholar
Zar, J.H. 1999. Biostatistical analysis. Prentice Hall Inc., Englewood Cliffs, New Jersey.Google Scholar
Zare, R., and Gams, W. 2001. A revision of Verticillium section Prostrata. IV. The genera Lecanicillium and Simplicillium gen nov. Nova Hedwigia, 73: 1–50.CrossRefGoogle Scholar
Zare, R., and Gams, W. 2003 a. Lecanicillium longisporum. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 1566. Kew, Surrey, United Kingdom.Google Scholar
Zare, R., and Gams, W. 2003 b. Lecanicillium muscarium. CMI Descriptions of Pathogenic Fungi and Bacteria. No. 1567. Kew, Surrey, United Kingdom.Google Scholar
Zare, R., Gams, W., and Culham, A. 2000. A revision of Verticillium section Prostrata. I. Phylogenetic studies using ITS sequences. Nova Hedwigia, 71: 465–480.CrossRefGoogle Scholar