Genetic Diversity of Bactericera cockerelli (Hemiptera: Triozidae) Based on Mitochondrial Gene Sequences: Implications for Haplotype Assignment

Bactericera cockerelli (Šulc) is one of the best‐studied hemipterans and a primary vector of Candidatus Liberibacter species affecting numerous Solanaceae crops globally. Previous studies have identified the western, northwestern, central, and southwestern mitochondrial haplotypes in the United States. Nevertheless, no sequence differences have been reported between the central and western haplotypes. This study aimed to evaluate the genetic diversity and haplotype assignment, as well as to reassess the global distribution of B. cockerelli using sequences from two regions of the mitochondrial cytochrome c oxidase subunit 1 ( cox1 ) gene. From 2021 to 2023, 128 specimens of B. cockerelli were collected from potato ( Solanum tuberosum L.) and husk tomato ( Physalis philadelphica Lam.) in the State of Mexico, Mexico. The specimens were identified by PCR amplification and sequencing of partial cox1 fragments using primers LCO1490/HCO2198 (~710 bp) and CO1F3/CO1R3 (~500 bp). Phylogenetic analyses revealed consistent topologies across both datasets, with all Mexican sequences clustering within a single major clade together with sequences previously assigned to the central and western haplotypes. Genealogical concordance analysis showed no evidence of recombination among phylogenetically closely related individuals in cox1 (Φw = 1). Network analysis identified 10 distinct haplotypes of B. cockerelli ; the cox1 diversity values were greater than 0.5 (Hd = 0.574), reflecting high genetic diversity and low nucleotide diversity ( π = 0.0125). Additionally, the neutrality statistic (Tajima's D) showed a negative value (−0.0486), suggesting population expansion in the B. cockerelli haplotype. These results suggest that the current nomenclature of B. cockerelli haplotypes should be based on mitochondrial molecular markers rather than geographical distribution.