D3058: Assessing seasonal hosts and transmission of beet curly top virus (BCTV) in the Columbia Basin

Pathogens transmitted by insect vectors like beet leafhopper (Circulifer tenellus) Baker (Homoptera: Cicadellidae) affect many agricultural crops and wild hosts. In the Western US, one such pathogen is beet curly top virus (BCTV; family Geminiviridae, genus Curtovirus), which can cause considerable losses in various vegetable, seed, and specialty crops. Control methods for BCTV primarily involve the management of leafhopper vectors. However, leafhoppers are notoriously difficult to control because they move among crop and non-crop hosts throughout seasons, and it remains unknown which weedy hosts are sources of infectious leafhoppers. To address these knowledge gaps, our objectives: (1) used molecular tools to assess prevalence of leafhopper-transmitted pathogens across landscape plant hosts, (2) assessed feeding habits and infection status of leafhoppers using gut content analyses, and (3) investigated whether BCTV evolves to specialize within hosts. Work involved sampling beet leafhoppers and associated host plants across Washington, Oregon, and Colorado. Results indicate which hosts are widely used by leafhoppers seasonally and regional inference into pathways of transmission among weeds and crops. Research will also assess how the BCTV pathogen evolves in different host species, and whether pathogen transmission among hosts changes over time. Overall, my research will provide considerable information on the phenology and ecology of beet leafhoppers and their associated pathogens to aid in developing management tactics which are shared on WSU’s Decision Aid System website. More broadly, my work shows how molecular techniques can complement traditional monitoring efforts to better understand the dynamics of insect vectors and vector-borne plant pathogens.