Electron beam irradiation reduces plant pathogen abundance and transmission by psyllids

Introduction: Candidatus Liberibacter solanacearum (Lso) is a bacterial pathogen that causes ‘zebra chip’ disease. Vectored by the potato psyllid Bactericera cockerelli, Lso also inflicts severe economic losses annually in solanaceous and other crops. Conventional management strategies have been insufficient to control the pathogen. As an environmentally friendly alternative, electron beam (eBeam) irradiation has been shown to drastically suppress psyllid growth and development. However, whether this chemical-free technology impacts its disease transmission remains to be investigated. Here, we study whether eBeam irradiation can significantly affect Lso transmission efficiency.

Results: 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. Electrical penetration graphs (EPG) revealed that eBeam substantially impacted psyllid feeding activity. On the other hand, 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, infected tomato plants were drastically reduced when fed by psyllids exposed to 250 Gy and undetectable at 500 Gy. 

Conclusion: eBeam irradiation curtailed Lso population in potato psyllids and impaired its bacterial transmission. Our results suggest that irradiation technology has real potential for management of insect-vectored diseases.

Reference: Chang, Y., J. Lei, A.E. Alvarez, T. Chappell, X. Tang, I.W. Chen, C. Penca, W.D. Bailey, S. Pillai, C. Tamborindeguy, Y. Du and K. Zhu-Salzman (2023). Entomologia Generalis 43: 441-450