Host and Shelter Plants for the Beet Leafhopper which Vectors Curly Top Viruses and Phytoplasmas in Southern Idaho

Weeds and crop plants not only serve as reproductive hosts and transitory or shelter plants for the beet leafhopper (BLH; Circulifer tenellus) but also as sources of plant pathogens that can then be vectored by the BLH. Thus, the plants that the BLH are feeding on and infecting is of interest and may be changing over time. Therefore, BLH samples from a recent survey were investigated through DNA barcoding via the rbcL and matK chloroplast gene regions to determine what the BLHs had been feeding on prior to capture on yellow sticky cards in southern Idaho during 2020 and 2021. In June both years, the first generation of BLHs predominately fed on Pinus spp. (59 to 76% of samples) which were likely in mountainous areas and dispersed approximately 48 to 80 km to crop and sagebrush steppe locations. During July to September, the BLH predominantly fed on Salsola spp. (Russian thistle; 61 to 66% of samples) and Bassia scoparia (Kochia; 15% of samples). Both years the BLHs that fed on pine had the highest percentage (55 and 75%, respectively) of samples with beet curly top virus based on primers that can detect both the Worland and Colorado strains. Both years, BLH that had fed on Russian thistle and alfalfa had the highest percentage of samples with Spinach curly top Arizona virus. These data will be utilized in the development of future curly top management plans.