Adaptability and 'Candidatus Liberibacter asiaticus' titres of Diaphorina citri adults on three weed species in China.

BACKGROUND: Diaphorina citri is a vector of 'Candidatus Liberibacter asiaticus' (CLas), which is associated with citrus huanglongbing (HLB). In this study, the adaptability and CLas titres of D. citri adults on three weed species, namely, Ageratum conyzoides, Solanum nigrum and Praxelis clematidea, which are widely distributed in citrus orchards in China, were determined. RESULTS: D. citri selected S. nigrum preferentially over the other weed species. The longest survival times of D. citri adults on A. conyzoides, S. nigrum and P. clematidea were 48, 41 and 11 days, respectively. On S. nigrum, the survivorship of females was significantly higher than that of males. The CLas titres of D. citri adults feeding on the three weeds for 1 week increased significantly during autumn but did not change significantly during spring. Conversely, the titres of adults on citrus increased significantly during spring but did not change significantly during autumn. CONCLUSION: D. citri exhibited different adaptabilities to the three weed species, but the CLas titres of D. citri adults did not decrease on any of the weeds. These results suggested that the three weed species could help dispersing of D. citri and transmission of CLas while ideal host conditions were scarce or absent. © 2021 Society of Chemical Industry.

Phytoseiid mites (Acari: Mesostigmata: Phytoseiidae) in Nanling National Nature Reserve, Guangdong, China.

Nanling National Nature Reserve is the biggest natural reserve in Guangdong Province. It is located on the south side of the Nanling middle mountain range, bordering on Hunan Province. During Oct. 28-Nov. 2, 2018, a survey was carried out to investigate the fauna of phytoseiid mites in Nanling National Nature Reserve. A total of 17 species in eight genera and two subfamilies was recorded, including two new species Transeius conyzoides Fang Wu sp. nov. and Typhlodromus (Anthoseius) huangjiaensis Fang Wu sp. nov. A checklist of all species is presented in this paper, and the two new species are described and illustrated.