Molecular ecology of host use and pathogen acquisition by an insect vector in potato crop fields

Generalist insect vectors are notoriously difficult to manage due to their ability to use a range of host plants within and across seasons. Improving vector management requires novel approaches that assess host use across space and time to predict pathogen transmission dynamics. Molecular gut content analysis of vector insects has been instrumental in identifying host use but has often been poorly linked with hosts related to pathogen transmission. Here, we integrate gut content analysis of vector insects with monitoring pathogen incidence to determine the role of various plant hosts in Neoaliturus tenellus (Baker) (beet leafhopper) movement and pathogen spread. We tested 226 beet leafhopper adults collected from 24 potato fields and nearby weeds over 3 growing seasons to assess host use and acquisition of beet curly top virus and ‘Candidatus Phytoplasma trifolii’. We observed seasonal variation in pathogen acquisition from host plants with N. tenellus acquiring pathogens from Sisymbrium spp. and Brassica spp. (wild mustards) in spring, whereas Salsola/Kali spp. (Russian thistle) and Bassia spp. (kochia) serve as the primary insect hosts during summer. Congruent with other recent research, we detected tree DNA in the guts of N. tenellus confirming tree probing or feeding, including Tilia spp. (linden), Prunus spp./Pyrus spp./Citrus spp (fruit), and Tsuga spp./Pinus spp. (pine). Our study refines our understanding of N. tenellus ecology and highlights the importance of host use patterns in predicting pathogen transmission, ultimately improving pathogen risk assessments.