Electron beam irradiation reduces plant pathogen abundance and transmission by potato psyllids

'Candidatus Liberibacter solanacearum' (Lso) is a bacterial pathogen that causes 'zebra chip' disease in potato. Vectored by the potato psyllid Bactericera cockerelli, Lso inflicts severe economic losses annually in solanaceous and other crops. Conventional management strategies have been insufficient to control the pathogen. As an environmentally friendly phytosanitary technique, electron beam (eBeam) irradiation has been shown to drastically suppress psyllid growth and development. However, whether this chemical-free technology negatively impacts the pathogen transmission remains to be investigated. In this study, we irradiated newly emerged adult psyllids and measured abundance of Lso they carried. An eBeam dose of 100 Gy significantly suppressed Lso in irradiated psyllids, although a rebound was detected on day 7 post irradiation. This resumed bacterial growth was not observed in psyllids irradiated at 250 or 500 Gy. Electrical penetration graphs revealed that eBeam substantially impacted psyllid feeding activity. No significant difference was detected in actin cytoskeleton structure and nucleus integrity of its midgut cells 1 or 7 days post eBeam irradiation at 500 Gy. Furthermore, infection of tomato plants was drastically reduced when fed upon by psyllids exposed to 250 Gy and undetectable at 500 Gy. Thus, eBeam significantly lowered psyllid's transmission efficiency and even abolished this capacity. Taken together, eBeam irradiation curtailed Lso titers in potato psyllids and impaired its bacterial transmission. Our results have demonstrated the real potential of irradiation technology in management of insect-vectored diseases.