Genetics of the potato psyllid (Bactericera cockerelli): Implications of pest distribution and population variability within the United States

Candidatus Liberibacter solanacearum is transmitted to potato, tomato and other solanaceous plants by the potato psyllid, Bactericera cockerelli (Sulc), and causes symptoms including leaf discoloration, decreased quantity and size of tubers, and characteristic tuber tissue necrosis known as Zebra Chip. Zebra Chip is economically significant to the potato chip industry because it reduces crop production, and infected tubers exhibit radial patterns when sliced and fried, making them unmarketable. Potato psyllids are migratory and can be found from Guatemala to Canada. Two genetically distinct biotypes exist; the first biotype is associated with the central portion of North America including Mexico, Texas, Nebraska, and Kansas, while the second biotype is associated with the West Coast including California and Washington. In this study, we distinguished between psyllid biotypes using a novel quantitative real-time PCR assay followed by high resolution melt curve analysis. The majority of the insect DNA evaluated thus far was from the Midwestern biotype. Genetic analysis via inter-simple sequence repeat PCR (ISSR-PCR) of potato psyllids collected from 10 locations within the United States in 2009 revealed a high degree of genetic variation, including 26 polymorphic bands in 51 banding patterns.