Polymerase chain reaction-restriction fragment-length polymorphism method to distinguish Liriomyza huidobrensis from L-langei (Diptera : Agromyzidae)applied to three recent leafminer invasions

A molecular method is presented for differentiating the morphologically cry ptic leafminers Liriomyza langei Frick and L. huidobrensis (Blanchard). Thi s method requires polymerase chain reaction (PCR) amplification of a 1031-b p region of mitochondrial cytochrome oxidase DNA followed by restriction fr agment analysis using the restriction enzymes SpeI and EcoRV. SpeI cuts the mitochondrial fragment of L. langei into two fragments, but does not cut t he L. huidobrensis fragment. EcoRV cuts the L. huidobrensis fragment into t wo fragments, but does not cut the L. langei fragment. This PCR-restriction fragment-length polymorphism (RFLP) method is faster and less costly than DNA sequencing, which is currently the only other way to differentiate thes e two species. We apply the method to samples from recently introduced leaf miner populations in Sri Lanka, Canada, and South Africa and find that the invasive leafminer in all three locations is L. huidobrensis.