Molecular-based approach to the differentiation of mealybug (Hemiptera : Pseudococcidae) species

The rDNA internal transcribed spacer (ITS) region of 4 mealybug species, Ps eudococcus viburni (Signoret), P. longispinus (Targiono-Tozzetti), P. calce olariae (Maskell), and P. similans (Lidgett), was isolated by polymerase ch ain reaction (PCR) amplification, cloned, and sequenced. In this region of the genome there were numerous differences; including nucleotide substituti ons, insertions, or deletions between P. viburni, P. longispinus, and P. ca lceolariae, whereas P. calceolariae and P. similans were very similar. Base d on sequence differences between the ITS regions, we designed PCR primers that were able to differentiate the 4 mealybug species and that correlated with morphological differences found between adult females of these species . The PCR amplification by using the species-specific primers enabled the d ifferentiation of not only adult females but also eggs, juveniles, and adul t males, which was not previously possible by using conventional identifica tion methods.