Hostname: page-component-848d4c4894-nmvwc Total loading time: 0 Render date: 2024-07-05T18:12:56.516Z Has data issue: false hasContentIssue false
  • English
  • Français

The role of Pityophthorus spp. as vectors of pitch canker affecting Pinus radiata

Published online by Cambridge University Press:  02 April 2012

Joyce M. Sakamoto ,
Thomas R. Gordon ,
Andrew J. Storer  and
David L. Wood
Joyce M. Sakamoto*
Affiliation:
Department of Plant Pathology, University of California, Davis, California 95616, United States of America
Thomas R. Gordon
Affiliation:
Department of Plant Pathology, University of California, Davis, California 95616, United States of America
Andrew J. Storer
Affiliation:
School of Forest Resources and Environmental Science, Michigan Technological University, Houghton, Michigan 49931, United States of America
David L. Wood
Affiliation:
Division of Insect Biology, University of California, Berkeley, California 94720, United States of America
*
2 Corresponding author (e-mail: jsaka001@umaryland.edu).
Get access Rights & Permissions [Opens in a new window]

Abstract

The fungus Fusarium circinatum Nirenberg and O’Donnell (Hypocreaceae) causes pitch canker, a disease affecting pines worldwide. In California, many native insect species have been implicated in transmission of F. circinatum. This study showed that two twig beetle species, Pityophthorus setosus Blackman and Pityophthorus carmeli Swaine (Coleoptera: Curculionidae: Corthylini), can make wounds on healthy Monterey pine (Pinus radiata D. Don (Pinaceae)) branches that are suitable for infection by the pitch canker pathogen. Because these two species are not known to engage in maturation feeding and the observed wounds were not associated with tunneling, we hypothesize that the wounds reflect “exploratory tasting” to assess the suitability of the substrate for colonization. This behavior would help to explain how twig beetles can serve as wounding agents on healthy host branches, which are not amenable to colonization by these insects. We tested two specific hypotheses: (1) two native species of Pityophthorus can create wounds on F. circinatum-contaminated trees that are sufficient for development of disease; and (2) the efficiency with which F. circinatum infects beetle wounds is affected by relative humidity. Under growth-chamber conditions, both Pityophthorus species indulged in exploratory behavior that caused wounds suitable for development of pitch canker. Field experiments did not confirm a significant effect of beetle activity on infection frequency, perhaps because of an overall low infection rate due to low temperatures. Experiments conducted under controlled conditions documented a significant effect of relative humidity on the success rate of twig beetle-initiated infections.

Résumé

Le champignon Fusarium circinatum Nirenberg et O’Donnell (Hypocreaceae) est responsable du chancre poisseux, une maladie qui affecte les pins à l’échelle planétaire. En Californie, plusieurs espèces d’insectes indigènes ont été reliées à la transmission de F. circinatum. Notre étude montre que deux scolytes des brindilles, Pityophthorus setosus Blackman et Pityophthorus carmeli Swaine (Coleoptera: Curculionidae: Corthylini), peuvent causer sur les branches de pins de Monterey (Pinus radiata D. Don (Pinaceae)) saines des blessures propres à permettre l’infection par le pathogène du chancre poisseux. Parce que ces deux espèces ne sont pas connues pour faire de l’alimentation de maturation et que les blessures observées ne sont pas associées à des galeries, notre hypothèse veut que ces blessures représentent des évaluations gustatives exploratoires de la convenance du substrat pour la colonisation. Ce comportement permettrait d’expliquer comment les scolytes des brindilles peuvent servir d’agents vulnérants sur les branches saines de l’hôte qui ne sont pas convenables pour la colonisation par ces insectes. Nous testons deux hypothèses spécifiques: (1) les deux espèces indigènes de Pityophthorus peuvent causer sur des arbres contaminés par F. circinatum des blessures suffisantes pour le développement de la maladie et (2) l’efficacité de l’infection à F. circinatum reliée aux blessures faites par les coléoptères est affectée par l’humidité relative. Dans des conditions de chambre de croissance, les deux espèces de Pityophthorus ont un comportement exploratoire qui cause des blessures suffisantes pour le développement du chancre poisseux. Des expériences de terrain ne confirment cependant pas l’existence d’un effet significatif de l’activité des coléoptères sur la fréquence des infections, peut-être à cause d’un taux global d’infection bas dû aux basses températures. Des expériences menées en conditions contrôlées indiquent un effet significatif de l’humidité relative sur le taux de succès des infections reliées aux scolytes des brindilles.

[Traduit par la Rédaction]

Type
Articles
Information
The Canadian Entomologist , Volume 139 , Issue 6 , December 2007 , pp. 864 - 871
Copyright
Copyright © Entomological Society of Canada 2007

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

Bonello, P., McNee, W.R., Storer, A.J., Wood, D.L., and Gordon, T.R. 2001. The role of olfactory stimuli in the location of weakened hosts by twig-infesting Pityophthorus spp. Ecological Entomology, 26: 8–15.CrossRefGoogle Scholar
Brasier, C. 1996. New horizons in dutch elm disease control. Report on Forest Research, Forestry Commission, Edinburgh, United Kingdom. pp. 20–28.Google Scholar
Bright, D.E. 1981. Taxonomic monograph of the genus Pityophthorus Eichhoff in North and Central America (Coleoptera: Scolytidae). Memoirs of The Entomological Society of Canada No. 118.CrossRefGoogle Scholar
Dallara, P.L. 1997. Studies on the distribution, interspecific relationships, host range, and chemical ecology of Pityophthorus spp. (Coleoptera: Scolytidae) and selected insectan associates, and their associations with Fusarium subglutinans f. sp. pini in central coastal California. Ph.D. dissertation, University of California, Berkeley, California.Google Scholar
Dallara, P.L., Seybold, S.J., Meyer, H., Tolasch, T., Francke, W., and Wood, D.L. 2000. Semiochemicals from three species of Pityophthorus (Coleoptera: Scolytidae): identification and field response. The Canadian Entomologist, 132: 889–906.CrossRefGoogle Scholar
Farrell, B.D., Sequeira, A.S., O'Meara, B.C., Normark, B.B., Chung, J.H., and Jordal, B.H. 2001. The evolution of agriculture in beetles (Curculinidae: Scolytinae and Platipodinae). Evolution, 55: 2011–2027.Google Scholar
Fox, J.W., Wood, D.L., and Koehler, C.S. 1990. Distribution and abundance of engraver beetles (Scolytidae: Ips spp.) on Monterey pines infected with pitch canker. The Canadian Entomologist, 122: 1157–1166.CrossRefGoogle Scholar
Fox, J.W., Schultz, M.E., Gordon, T.R., and Wood, D.L. 1991. Engraver beetles (Scolytidae: Ips species) as vectors of the pitch canker fungus, Fusarium subglutinans. The Canadian Entomologist, 123: 1355–1367.CrossRefGoogle Scholar
Gordon, T.R., Okamoto, D., Storer, A.J., and Wood, D.L. 1998. Susceptibility of five landscape pines to pitch canker disease, caused by Fusarium subglutinans f. sp. pini. Hortscience, 33: 868–871.CrossRefGoogle Scholar
Gordon, T.R., Storer, A.J., and Wood, D.L. 2001. The pitch canker epidemic in California. Plant Disease, 85: 1128–1139.CrossRefGoogle ScholarPubMed
Gordon, T.R., Kirkpatrick, S.C., Aegerter, B.J., Wood, D.L., and Storer, A.J. 2006. Susceptibility of Douglas-fir (Pseudotsuga menziesii) to pitch canker, caused by Gibberella circinata (anamorph = Fusarium circinatum). Plant Pathology, 55: 231–237.CrossRefGoogle Scholar
Guérard, N., Dreyer, E., and Lieutier, F. 2000. Interactions between Scots pine, Ips acuminaus (Gyll.) and Ophiostoma brunneo-ciliatum (Math.): estimation of the critical thresholds of attack and inoculation densities and effects on hydraulic properties in the stem. Annals of Forest Science, 57: 681–690.CrossRefGoogle Scholar
Hoover, K., Wood, D.L., Fox, J.W., and Bros, W.E. 1995. Quantitative and seasonal association of the pitch canker fungus, Fusarium subglutinans f. sp. pini with Conophthorus radiatae (Coleoptera: Scolytidae) and Ernobius punctulatus (Coleoptera: Anobiidae) which infest Pinus radiata. The Canadian Entomologist, 127: 79–91.CrossRefGoogle Scholar
Hoover, K., Wood, D.L., Storer, A.J., Fox, J.W., and Bros, W.E. 1996. Transmission of the pitch canker fungus, Fusarium subglutinans f. sp. pini, to Monterey pine, Pinus radiata, by cone- and twig-infesting beetles. The Canadian Entomologist, 128: 981–994.CrossRefGoogle Scholar
Inman, A., and Gordon, T.R. 2005. Temperature as a potential barrier for the spread of pitch canker. Phytopathology, 95: S46.Google Scholar
Lanier, G.N. 1982. Dutch elm disease: a postscript. Arnoldia, 42: 78–87.Google Scholar
Leach, J.G. 1940. Insect transmission of plant diseases. McGraw-Hill Book Company, Inc., New York.Google Scholar
Lindgren, B.S. 1983. A multiple funnel trap for scolytid beetles (Coleoptera). The Canadian Entomologist, 115: 299–302.CrossRefGoogle Scholar
McCain, A.H., Koehler, C.S., and Tjosvold, S.A. 1987. Pitch canker threatens California pines. California Agriculture, 41: 22–23.Google Scholar
McNee, W.R., Wood, D.L., Storer, A.J., and Gordon, T.R. 2002. Incidence of the pitch canker pathogen and associated insects in intact and chipped Monterey pine branches. The Canadian Entomologist, 134: 47–58.CrossRefGoogle Scholar
Sakamoto, J.M. 2004. Exploring the roles of environmental factors and the twig beetle, Pityophthorus spp. (Coleoptera: Scolytidae) in the epidemiology of pitch canker of Pinus radiata. Ph.D. dissertation, University of California, Davis, California.Google Scholar
Sakamoto, J.M., and Gordon, T.R. 2006. Factors influencing infection of mechanical wounds by Fusarium circinatum on Monterey pines (Pinus radiata). Plant Pathology, 55: 130–136.CrossRefGoogle Scholar
Sokal, R.R., and Rohlf, F.J. 2003. Biometry. 3rd ed. W.H. Freeman and Company, New York.Google Scholar
Steel, R.G.D., Torrie, J.H., and Dickey, D. 1997. Principles and procedures of statistics: a biometrical approach. 3rd ed. The McGraw-Hill Company, Inc., New York.Google Scholar
Storer, A.J., Wood, D.L., and Gordon, T.R. 2004. Twig beetles, Pityophthorus spp. (Coleoptera: Scolytidae) as vectors of the pitch canker pathogen, Fusarium circinatum in California. The Canadian Entomologist, 136: 685–693.CrossRefGoogle Scholar
Wikler, K., Storer, A.J., Newman, W., Gordon, T.R., and Wood, D.L. 2003. The dynamics of an introduced pathogen in a native Monterey pine (Pinus radiata) forest. Forest Ecology and Management, 179: 209–221.CrossRefGoogle Scholar