No abstract

Mealybug (Hemiptera: Pseudococcidae) has emerged as a new cotton pest in Pakistan in recent years. We used DNA nucleotide sequences and PCR-RFLP, respectively, as tools for mealybug characterization and species composition. Partial nucleotide sequences of nuclear (elongation factor-1a, ribosomal DNA subunits 18S and 28S) and mitochondrial (COI) genes were used for species characterization, and the combined ITS1-5.8S-ITS2 sequences of rDNA were used for PCR-RFLP analyses. Homology searches of the nuclear genes indicated that the mealybug species damaging cotton in Pakistan belonged to the genus Phenacoccus. Further, the barcoding sequence of COI showed a significant nucleotide similarity with Phenacoccus solenopsis. PCR-RFLP analysis with three different endonucleases did not show restriction site differences among mealybug individuals collected from various host plants and geographical locations. This is the first DNA-based characterization of cotton mealybug from Pakistan and the findings will help in decision making while considering a biological control program.

Abstract. Mango orchards in Pakistan are attacked by the scale insect, Drosicha mangiferae (Hemiptera: Monophlebidae), commonly called the "mango mealybug". This insect is univoltine, active from December through May and targets multiple host plants. We used DNA nucleotide sequences to characterize and determine the phylogenetic status of D. mangiferae. Mango mealybugs were collected from several tree species from different localities and patterns of phylogenetic and genetic diversity were examined at both nuclear (18S, ITS1) and mitochondrial (COI) genes. Phylogenetic analysis confirms that the mango mealybug belongs to the family Monophlebidae. Minor genetic differences in both the ITS1 and the COI barcode region were noted among D. mangiferae collected from different geographic localities. These genetic differences revealed the existence of two genotypes of D. mangiferae that are region specific but not host-specific.