Epidemiology of beet curly top virus and purple top phytoplasma in the Northern Columbia Basin of Washington State

Presenting Author(s)

Camille Wagstaff

Research Assistant
Washington State University
Pullman, Washington

Co-Author(s)

DC

David Crowder

Associate Professor
Washington State University
Pullman, Washington

The beet leafhopper (Circulifer tenellus Baker) vectors two extensive problems in the Columbia Basin of Washington: Beet Curly Top Virus (BCTV) and purple top disease caused by Candidatus Phytoplasma trifolii or Beet Leafhopper-Transmitted Virescence Agent (BLTVA). To determine which plant species are common hosts of beet leafhoppers infected with curly top and purple top in the Columbia, gut content analysis has been performed on beet leafhoppers collected 2019-2022. The DNA was extracted from individual beet leafhoppers and the samples were barcoded before sequencing for plant gut content using PacBio and Illumina. The DNA from the beet leafhoppers was also tested for BCTV and BLTVA using qr-PCR. The results for BCTVA and BLTVA infections were compared with gut contents to determine which plant species were most commonly fed upon by viruliferous beet leafhoppers. Preferred hosts of beet leafhoppers belong in the Amaranthaceae, Solanaceae, and Brassicaceae families. Of economic importance are potato, radish, lettuce, spinach, cannabis, and rapeseed. Major weedy hosts include Russian thistle, kochia, and pigweed. This information is important for determining which hosts are the biggest reservoirs of pathogens and aid in better understanding phenological timing to establish better epidemiological risk calendars. Better understanding of highest risk times can lead to more precise pest management and reductions in unnecessary pesticide application.