Assessing potato psyllid haplotypes in potato crops in the Pacific Northwestern United States

Authors: Swisher Grimm, Kylie; SENGODA, VENKATESAN - Washington State University; DIXON, JACOB - US Department Of Agriculture (USDA); Munyaneza, Joseph - Joe; MURPHY, ALEXZANDRA - Oregon State University; RONDON, SILVIA - Oregon State University; THOMPSON, BRANDON - University Of Idaho; KARASEV, ALEXANDER - University Of Idaho; WENNINGER, ERIK - University Of Idaho; OLSEN, NORA - University Of Idaho; Crosslin, James

Submitted to: American Journal of Potato Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/31/2014
Publication Date: 3/3/2014
Citation: Swisher, K.D., Sengoda, V.G., Dixon, J., Munyaneza, J.E., Murphy, A.F., Rondon, S.I., Thompson, B., Karasev, A.V., Wenninger, E.J., Olsen, N., Crosslin, J. 2014. Assessing potato psyllid haplotypes in potato crops in the Pacific Northwestern United States. American Journal of Potato Research. DOI:10.1007/s12230-014-9378-8.

Interpretive Summary: The potato psyllid is a vector of the recently discovered bacterium that has been linked to the economically devastating zebra chip disease of potato. Four genetic variants of this insect have been identified correlating to geographic regions of the United States and are referred to as Central, Western, Northwestern, and Southwestern variants. Researchers at USDA-ARS Prosser and Wapato in Washington, in collaboration with scientists at Oregon State University and University of Idaho determined seasonal changes in populations of these psyllid variants in potato crops in the Pacific Northwest. It was discovered that the Northwestern variant predominates in Washington and Oregon whereas the Western variant is predominant in Idaho, requiring different management strategies depending on each region. Information from this research will help growers in the Pacific Northwest protect their potato crops from zebra chip by targeting the most important psyllid variant for control.

Technical Abstract: The potato psyllid, Bactericera cockerelli (Šulc), is a vector of the bacterium ‘Candidatus Liberibacter solanacearum’ (Lso) that has been linked to the economically devastating zebra chip disease of potato. To date, four haplotypes of the potato psyllid have been identified and include Central, Western, Northwestern, and Southwestern haplotypes. Zebra chip was reported in potato crops in the Pacific Northwestern United States for the first time in 2011, and the Lso-infected psyllids collected from zebra chip-affected fields were identified as the Western haplotype. Additional studies have reported a mix of the Western and Northwestern psyllid haplotypes in the Pacific Northwest. The present study further examined psyllid population dynamics over the duration of the 2012 potato season in the Pacific Northwest by haplotype analysis of 864 potato psyllids collected from potato fields in Washington, Oregon, and Idaho. In the Yakima Valley of Washington and the lower Columbia Basin of Washington and Oregon, the Northwestern haplotype was predominant (78%), and was detected earlier in the season than the Western haplotype. Interestingly, in south-central Idaho, all four psyllid haplotypes were identified, but the predominant haplotype was the Western haplotype (77%). Here, Northwestern psyllids were detected early in the season from June to mid-August, whereas Central psyllids were detected in late July and thereafter. These results suggest that haplotype composition of psyllid populations in potato fields throughout the 2012 growing season in south-central Idaho differed greatly from those in Washington and Oregon. Additionally, all psyllids were analyzed for the presence of Lso, and no Lso-positive psyllids were found in Washington and Oregon. Psyllids from south-central Idaho that were Lso-positive consisted of the Western, Northwestern, and Central haplotypes.