Temporal Rhythm Affects the Efficiency of Asian Citrus Psyllid (<i>Diaphorina citri</i>) to Acquire Huanglongbing Pathogen

Abstract

Huanglongbing, commonly known as citrus greening, is a devastating disease of citrus worldwide. Candidatus liberibacter asiaticus is the putative cause of citrus greening disease in China and is spread through the process of plant grafting and feeding by insect vectors. Asian citrus psyllid (Diaphorina citri) is a destructive pest due to insecticide resistance development and the main cause of dissemination of Huanglongbing. The purpose of this study was to determine the level of Huanglongbing present in Guangdong province and the acquisition of the pathogen by D. citri through feeding. Six different city areas of Guangdong province were sampled. The results demonstrated that Yunfu currently has the highest infestation rate of CLas in Guangdong province, followed by Chaozhou, Jiangmen, and Foshan. In comparison, Zhongshan and Maoming have the lowest infestation rates. Results also showed that CLas acquisition was directly proportional to the insect feeding duration. The longer an insect fed on an infested plant, the more CLas it acquired. The acquisition efficiency of the pathogen was higher at night compared to during the daytime. During the time period of 15:00–07:00 D. citri acquires more pathogens than during the period of 07:00–15:00. This study provides a basic understanding of the feeding pattern of D. citri, which aids in devising a management program for effective control of direct and indirect losses caused by D. citri.

Keywords

• citrus greening
• <i>Candidatus</i> liberibacter
• Nested-PCR
• feeding duration
• infection level
• insect vector