Transmission potential of the zebra chip disease pathogen “Candidatus Liberibacter solanacearum” by whitefly and thrips on potato

Zebra chip (ZC), a new and economically important disease of potato in the USA, Mexico, Central America, and New Zealand, is causing millions of dollars in losses to the potato industry. The putative ZC pathogen is the bacterium “Candidatus Liberibacter solanacearum” (Lso), which is vectored by the potato psyllid, Bactericera cockerelli (Sulc). Other than the potato psyllid, no other potato-feeding insects have so far been reported as vectors of Lso. Because of international quarantines on U.S. potatoes due to the concern that insects other than the potato psyllids may transmit Lso to potato, risk information on potential alternative vectors of ZC is needed. The current study determined the potential for Bemisia tabaci and Frankliniella fusca to acquire and transmit Lso to potato under greenhouse conditions. Preliminary results from PCR tests showed that F. fusca reared on ZC-infected plants has the potential ability to acquire Lso, with 35% extracted DNA samples testing positive for the bacterium, whereas no B. tabaci DNA samples were positive. Further experiments are needed to determine if F. fusca can transmit Lso to potato.