The tomato potato psyllid (TPP, Bactericera cockerelli) is an important plant pest as well as a vector of Candidatus Liberibacter solanacearum, the putative causative agent of Zebra Chip disease in potato. A region in the 3’ end of the mitochondrial cytochrome oxidase 1 gene has been used to distinguish between populations of TPP in the USA and Central America. Four different biotypes have been described based on 1-17 single nucleotide polymorphisms found in this 500 base pair region. Of these, three have been shown to differ biologically. All four biotypes are found in different geographical regions of the USA, but only the Western biotype has been described as an invasive population: it is able to overwinter in California and has established populations there as well as in parts of the Pacific Northwest.
It was also the Western biotype that was introduced into New Zealand, probably due to illegal importation of infested plant material. This biotype has been able to establish itself and is now found throughout the country.
To study the population structure and genetics of TPP in New Zealand, we collected TPP from the major potato-growing regions over several growing seasons. TPP were also collected from two regions in Honduras. DNA was extracted from individual insects and sequenced via Illumina HiSeq. From these data, 198 near-complete mitochondrial genome sequences were assembled. Phylogenetic and median joining network-based analyses clustered the New Zealand samples with sequences from California and Washington State. The insects from Honduras clustered separately from the New Zealand insects. These analyses illustrate significantly higher variation in the psyllid populations than described previously. The diversity in the mitochondrial sequences suggests accompanying differences in the nuclear genome which may translate into biological differences.