Feeding behavior of Diaphorina citri (Hemiptera: Liviidae) and its acquisition of ‘Candidatus Liberibacter asiaticus’, on huanglongbing-infected Citrus reticulata leaves of several maturity stages

Authors

  • Xiaozhu Luo Laboratory of Insect Ecology/Citrus Huanglongbing Research Laboratory, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
  • Alan L. Yen Biosciences Research Division, Department of Environment and Primary Industries, Bundoora, Victoria, 3083, Australia School of Applied Systems Biology, La Trobe University, Bundoora, Victoria, 3083, Australia
  • Kevin S. Powell Biosciences Research Division, Department of Environment and Primary Industries, Rutherglen, Victoria, 3685, Australia
  • Fengnian Wu Laboratory of Insect Ecology/Citrus Huanglongbing Research Laboratory, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
  • Yanjing Wang Laboratory of Insect Ecology/Citrus Huanglongbing Research Laboratory, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
  • Lixia Zeng Laboratory of Insect Ecology/Citrus Huanglongbing Research Laboratory, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
  • Yuzhi Yang Laboratory of Insect Ecology/Citrus Huanglongbing Research Laboratory, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China
  • Yijing Cen Laboratory of Insect Ecology/Citrus Huanglongbing Research Laboratory, South China Agricultural University, Wushan Road 483, Tianhe District, Guangzhou 510642, China

Keywords:

Asian citrus psyllid, HLB, leaf age, electrical penetration graph, pathogen acquisition, citrus

Abstract

The Asiatic citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the main vector of the Asiatic form of huanglongbing (HLB), the putative cause of which is a phloem-limited bacterium ‘Candidatus Liberibacter asiaticus’ (‘CLas’) (α-Proteobacteria). Nymphal and adult D. citri prefer to feed on young leaves of their host plants. Adults feeding on mature leaves are not considered very important by some Chinese farmers in the management of HLB. This study examined feeding by adult D. citri on ‘CLas’-infected citrus leaves of several maturity stages. Diaphorina citri adults from a ‘CLas’-free colony were tested for feeding behavior and the efficiency of their acquisition of ‘CLas’ from new shoots, and young and mature leaves. Probing and feeding behavior were monitored using the electrical penetration graph (EPG) technique, and pathogen acquisition efficiencies were tested by qPCR. The results showed that some EPG variables were significantly influenced by host-plant leaf maturity. The duration of waveform C (pathway phase) on new shoots was significantly longer than that on young leaves and mature leaves. In contrast, the duration of waveform E2 (phloem ingestion) was significantly shorter on new shoots and young leaves than on mature leaves. However, the duration taken for stylets of adult D. citri to reach the phloem and commence ingestion was not related to leaf maturity status. The qPCR results indicated that 23 of the 24 adults for which E2 waveforms were recorded harbored ‘CLas’. In addition, the minimum period of E2 waveform of these individuals was only 2 min. Proportions of ‘CLas’-positive adults feeding on mature leaves, young leaves and new shoots, were 55%, 40% and 35%, respectively. The main EPG variables were not significantly different between the males and females. Our results suggest that the acquisition of ‘CLas’ by adult D. citri is highly efficient, even when feeding on mature leaves. Therefore to effectively manage both vector and pathogen, D. citri populations should be monitored carefully, even when the trees stop producing new growth.

 

Resumen

El psílido de los cítricos asiático, Diaphorina citri Kuwayama (Hemiptera: Liviidae), es el vector principal de la forma asiática de Huanglongbing (HLB), la supuesta causa de que es una bacteria limitada al floema ‘Candidatus Liberibacter asiaticus’ (‘CLas’) (α-Proteobacteria). Las ninfas y adultos de D. citri prefieren alimentarse de las hojas jóvenes de sus plantas hospederas. Los adultos que se alimentan de las hojas maduras no son considerados muy importantes por parte de algunos agricultores chinos en cuanto al manejo de HLB. Este estudio examinó la alimentación de adultos de D. citri en hojas de cítricos de varios estados de madurez. infectadas con ‘CLas’. Se probaron adultos de Diaphorina citri de una colonia libre de ‘CLas’ para su comportamiento de alimentación y su eficiencia para la adquisición de ‘CLas’ en nuevos brotes y hojas jóvenes y maduras. Se realizó un monitoreo del comportamiento de prueba de plantas y su alimentación por medio de la técnica Gráfico de Penetración Eléctrica (GPE), y la eficiencia de adquisición de patógenos fueron probados por qPCR. Los resultados mostraron que algunas variables de GPE influyó significativamente en la madurez de la hoja de la planta hospedante. La duración de la forma de onda C (fase de vía) en nuevos brotes fue significativamente más larga que en las hojas jóvenes y hojas maduras. En contraste, la duración de la forma de onda de E2 (ingestión floema) fue significativamente más corta en nuevos brotes y hojas jóvenes que en las hojas maduras. Sin embargo, la duración tomada por las estiletes de adultos de D. citri para llegar al floema y comenzar la ingestión no fue relacionada con el estado de madurez de la hoja. Los resultados de qPCR indicaron que 23 de los 24 adultos en que registraron formas de onda E2 tenian ‘CLas’. Además, el período mínimo de forma de onda de E2 de estos individuos fue sólo 2 minutos. La proporcióon de los adultos ‘CLas ‘ positivos se alimentan de las hojas maduras, hojas jóvenes y nuevos brotes, fue 55%, 40% y 35% respectivamente. Las principales variables de GPE no fueron significativamente diferentes entre los machos y hembras. Nuestros resultados sugieren que la adquisición de ‘CLas’por adultos de D. citri es muy eficiente, incluso cuando se alimentan de las hojas maduras. Por lo tanto, para el manejo eficaz de poblaciones del vector y patógenos de D. citri, se debe realizar un monitoreo cuidadoso, incluso cuando los árboles dejan de producir un nuevo crecimiento.

 

View this article in BioOne

Downloads

Issue

Vol. 98, No. 1 (March 2015)

Section

Research Papers

License

Copyright for any article published in Florida Entomologist is held by the author(s) of the article. Florida Entomologist is an open access journal. Florida Entomologist follows terms of the Creative Commons, Attribution Non-Commercial License (cc by-nc). By submitting and publishing articles in Florida Entomologist, authors grant the FOJ and Florida Entomologist's host institutions permission to make the article available through Internet posting and electronic dissemination, and to otherwise archive the information contained both electronically and in a hard printed version. When used, information and images obtained from articles must be referenced and cited appropriately. Articles may be reproduced for personal, educational, or archival purposes, or any non-commercial use. Permission should be sought from the author(s) for multiple, non-commercial reproduction. Written permission from the author(s) is required for any commercial reproduction.