a1 Department of Entomology, University of Wisconsin-Madison, Madison, USA
a2 Institut Français de Recherche Scientifique pour le Développement en Cooperation (ORSTROM) Nouméa, New Caledonia.
The coffee berry borer Hypothenemus hampei (Ferrari) has recently evolved high levels of resistance to endosulfan and other cyclodiene-type insecticides in New Caledonia. During population outbreaks this has contributed to levels of infestation of coffee berries reaching up to 90%. Using degenerate primers in the polymerase chain reaction (PCR) we have amplified a section of the cyclodiene resistance gene Rdl from H. hampei. This gene codes for a γ-aminobutyric acid (GABA) gated chloride ion channel. Here we report that resistant strains of H. hampei carry exactly the same single amino acid replacement (alanine to serine) as that found in resistant Drosophila melanogaster (Meigen) (Diptera: Drosophilidae). A molecular diagnostic based upon PCR-mediated amplification of specific alleles (PASA) is described. This technique is capable of detecting resistance or susceptibility in adults, larvae or eggs but not in susceptible females carrying resistant sperm. Its potential use in field monitoring is discussed.
(Accepted October 26 1993)
c1 Dr R H ffrench-Constant, Department of Ento mology, 237 Russell Laboratories, 1630 Linden Drive, University of Wisconsin-Madison, Madison, WI 53706, USA.