Host-Choice Behavior of Diaphorina citri Kuwayama (Hemiptera: Psyllidae) Under Laboratory Conditions

The Asian citrus psyllid (ACP), Diaphorina citri Kuwayama, is the vector of the bacterial pathogens that cause Huanglongbing (HLB), considered to be the most devastating disease of citrus worldwide. Knowledge of the ACP's host-plant finding behavior aids in our understanding of the epidemiology of HLB and in designing experiments to investigate host plant resistance to ACP. We present the results of research conducted to assess the ability of adult ACP to distinguish between a non-host plant [Rhododendron simsii Planch. (Ericales: Ericaceae)] and two host plant species [Murraya paniculata (L.) Jack and Lugan Citrus reticulata Blanco (Sapindales: Rutaceae)] in a caged, free-choice situation. After being introduced into cages with the three plant species, more than 9 h elapsed before adult ACP made definite plant choices. Subsequently for more than 7 days, although adults were observed on R. simsii each time the plants were inspected, greater numbers were usually observed on M. paniculata or C. reticulata. Ultimately, most adults were on C. reticulata, intermediate numbers were on M. paniculata, and few were on R. simsii. However, at least some ACP adults were always observed on R. simsii, suggesting that adults regularly moved within a cage among the plant species. Regular movement of adults between plants would favor dissemination not only of its population but also of HLB. Adult ACP showed a strong preference for settling on flush leaves as opposed to mature leaves or other plant locations, and larger flush shoots were as attractive as tiny new shoots. It is well known that host plant volatiles such as those associated with flush attract ACP adults and regulate how fast and where they settle on a plant.