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POSTERS: Pathogen-vector/insect interactions

Infection by ‘Candidatus Liberibacter solanacearum’ haplotypes and psyllid survival in different solanaceous hosts
Fekede Workneh - Texas A&M AgriLife Research. Charles Rush- Texas A&M Agaric Experiment Station, Li Paetzold- Texas A&M AgriLife Research

Candidatus Liberibacter solanacearum’ (Lso), transmitted by the potato psyllid (Bactericera Cockerelli), putatively causes potato zebra chip (ZC). The bacterial organism has a wide host range, primarily in the Solanaceae family, including peppers, potatoes, and tomatoes. Currently there are two commonly detected haplotypes of Lso (A & B) in the US, which can be detected individually or as an A & B mix in psyllids or plant samples. Experiments were conducted in 2017 and 2018 in the greenhouse to determine whether there are interactions between Lso haplotypes and different solanaceous hosts. Peppers, potatoes, and tomatoes were infested with six psyllids per plant carrying either Lso A, B, A & B mix, or Lso-negative psyllids. Infested plants were maintained in replicated cages of each haplotype. Seven weeks after infestation, plants were sampled and tested with qPCR for Lso detection and adult psyllids in each cage were counted. Individual psyllids carrying haplotypes B, A & B mix, and those free of Lso reproduced well on all three hosts, and plant samples, except those infested with Lso-negative psyllids, tested positive for the respective Lso haplotype. However, psyllids carrying Lso A did not survive on peppers but did survive and reproduce on potatoes and tomatoes. In addition, samples from peppers infested with psyllids carrying Lso A tested negative for Lso. However, peppers infested with psyllids carrying Lso A & B mix tested positive for Lso A, indicating that the presence of Lso B may be required for pepper infection by Lso A and psyllid survival on peppers.