'Candidatus Liberibacter asiaticus' detected in Cacopsylla citrisuga
Studies have been conducted in the province of Yunnan (China) to determine whether the pomelo psyllid, Cacopsylla citrisuga (Hemiptera: Psyllidae), might be a potential vector of 'Candidatus Liberibacter asiaticus' (associated with citrus huanglongbing – EPPO A1 List). C. citrisuga feeds on Citrus spp. (e.g. Citrus grandis, C. reticulata, C. medica) and is only known to occur in China. Nymphs of C. citrisuga (all stages) and young citrus leaves were collected from a 6-year old lemon orchard (C. limon cv. ‘Eureka’) severely affected by huanglongbing. Samples were tested in the laboratory for the presence of 'Ca. Liberibacter asiaticus' by PCR assays. Results confirmed the presence of ‘Ca. L. asiaticus’ in diseased lemon trees, as well as in 12 (out of 29) nymphs of C. citrisuga. These results demonstrate that C. citrisuga can carry the pathogen, but further studies are under way to determine whether infected psyllids can transmit ‘Ca. L. asiaticus’ to healthy citrus trees.
Sources
Cen Y, Zhang L, Xia Y, Guo J, Deng X, Zhou W, Sequeira R, Gao J, Wang Z, Yue JQ, Gao Y (2012) Detection of 'Candidatus Liberibacter asiaticus' in Cacopsylla (Psylla) citrisuga (Hemiptera: Psyllidae). Florida Entomologist 95(2), 304-311.