The role of silicon and chitosan in entomopathogenic fungi pathogenicity against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae)

Environmental imbalances, such as widespread resistance caused by indiscriminate insecticide spraying, have driven the adoption of alternative methods for pest management in specialty crops. One such approach is Integrated Pest Management (IPM), which promotes sustainability by implementing various control tactics. This IPM study aimed to evaluate the combined effect of entomopathogenic fungi (EPF) and plant resistance inducers (PRI), specifically silicon and chitosan, against the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae). A greenhouse experiment was conducted at the State University of Londrina, Brazil, using Beauveria bassiana, both alone and in combination with silicon and chitosan. Mortality rates were recorded at 192 hours post-application. Results showed that the combination treatment significantly increased D. citri mortality (84.4%) compared to the fungus alone (32.2%). These findings suggest that PRIs can enhance EPF pathogenicity and may offer a promising tool to improve biological control efficacy under suboptimal environmental conditions. These results will serve as theoretical basis for applied field-based studies to be explore and refine application strategies for psyllid and citrus IPM programs.