Abstract
The sap beetle, Colopterus truncatus (Coleoptera: Nitidulidae), is one of the primary vectors of the oak wilt pathogen, Ceratocystis fagacearum, in the north-central United States. Field behavioral assays utilizing various release rates and blends of three methyl-branched hydrocarbon aggregation pheromone components showed that flight responses of this beetle were similar in Illinois and Minnesota populations. In both locations, both sexes of the beetle responded synergistically to a combination of the three-component pheromone and fermenting whole-wheat bread dough. Further, Colopterus truncatus preferred a high release rate over a low release rate of the three-component blend. In both locations, the response of C. truncatus to a simplified version of the pheromone consisting of (2E,4E,6E)-3,5-dimethyl-2,4,6-octatriene (1) and (2E,4E,6E,8E)-3,5,7-trimethyl-2,4,6,8-decatetraene (3) was not significantly different from the response to the three-component blend. An experiment in Illinois with all possible combinations of the components demonstrated that the decatetraene (3) was the crucial component in the blend; of all treatments, the maximal response was elicited by 3 + dough. Chipped bark, phloem, and xylem from northern pin oak, Quercus ellipsoidalis, was not attractive to C. truncatus in Minnesota. During a weekly survey over two seasons in Minnesota, C. truncatus flew in response to the three-component pheromone between early April and early July, with the maximum responses coming on May 4, 2000 and April 20, 2001. During both years, more than 98% of the beetles were trapped between April 14 and June 1. During the same survey, Glischrochilus spp. (Nitidulidae) flew during longer periods of the summer, particularly in 2001. The sex ratio of C. truncatus responding during all experiments was female-biased (1.8:1, female-male), which is characteristic of other male-produced coleopteran aggregation pheromones. Other sap beetles that play a minor role in the pathobiology of C. fagacearum also responded in experiments conducted in Minnesota. Carpophilus brachypterus Say was cross-attracted to the two- and three-component blends of the C. truncatus pheromone and dough, whereas two Glischrochilus spp. were attracted to all treatments that contained dough.
Original language | English (US) |
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Pages (from-to) | 1527-1547 |
Number of pages | 21 |
Journal | Journal of Chemical Ecology |
Volume | 28 |
Issue number | 8 |
DOIs | |
State | Published - Aug 2002 |
Bibliographical note
Funding Information:Acknowledgments—We thank Bruce W. Zilkowski of the National Center for Agricultural Utilization Research for doing the HPLC purification of components 1, 2, and 3; Roger D. Moon of the University of the Minnesota Department of Entomology for assistance with statistical analyses; and Julie A. Tillman of the University of Minnesota Department of Horticulture for assistance with graphics. We also thank Thomas W. Phillips of the Oklahoma State University, Department of Entomology and Thomas C. Skalbeck of the University of Minnesota Department of Entomology for helpful discussions. The Minnesota studies were funded in part by a grant from the Minnesota Environment and Natural Resources Trust fund as recommended by the Legislative Commission on Minnesota Resources—project title, “Development and Assessment of Oak Wilt Control Strategies: Life Histories of Principal Insect Vectors of the Oak Wilt Fungus” to J.J. and S.J.S., by Multistate Research Project W-189, “Biorational Methods for Integrated Pest Management: Bioorganic and Molecular Approaches,” by a Dayton-Wilkie Grant for Natural History Research to J.F.K., and by the H. Chiang scholarship to J.F.K. The work described in this paper is a portion of a MS thesis by J.F.K. and is a contribution of the Minnesota Agricultural Experiment Station (Project MN-17-070).
Keywords
- Aggregation pheromone
- Carpophilus brachypterus
- Ceratocystis fagacearum
- Coleoptera
- Colopterus truncatus
- Glischrochilus spp.
- Methy-branched hydrocarbons
- Monitoring
- Nitidulidae
- Oak wilt
- Phenology
- Sap beetle