A MOLECULAR DIAGNOSTIC FOR ENDOSULFAN INSECTICIDE RESISTANCE IN THE COFFEE BERRY BORER HYPOTHENEMUS-HAMPEI (COLEOPTERA, SCOLYTIDAE)

The coffee berry borer Hypothenemus hampei (Ferrari) has recently evol ved high levels of resistance to endosulfan and other cyclodiene-type insecticides in New Caledonia. During population outbreaks this has co ntributed 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 gamma-aminobutyric acid (GABA) gated ch loride ion channel. Here we report that resistant strains of H. hampei carry exactly the same single amino acid replacement (alanine to seri ne) as that found in resistant Drosophila melanogaster (Meigen) (Dipte ra: Drosophilidae). A molecular diagnostic based upon PCR-mediated amp lification 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 pot ential use in field monitoring is discussed.