The effect of volatiles on host-plant finding behavior of adult potato psyllids, Bactericera cockerelli (Hemiptera: Psyllidae): implications for reducing zebra chip disease incidence

One of the requirements in developing resistant crop varieties is in-depth information about interactions between host-plants and their pests. Among the cues used by insects to locate and choose a suitable host plant, plant volatile cues play an important role. We explored the effect of potato plant volatiles on host-plant finding behavior of adult potato psyllids, the only known vectors of zebra chip (ZC) disease pathogen, which causes millions of dollars in losses to potato producers and processors. Based on fields trials from an on-going breeding program, four potato varieties with low ZC infection rate and two commercial varieties (Atlantic and Russet) were included in a 6-choice bioassay of oviposition preference and corresponding volatile profiling. The metabolite, Germacrene-D, was produced in comparatively high amount in one potato variety, which received consistently low oviposition (non-preferred) by potato psyllids. Germacrene-D is known as an insect repellent and has been shown to “overshadow” the effect of attractive plant volatiles. Results from the combination of choice bioassay and volatile data are discussed in the context of developing potato varieties that are less attractive to potato psyllids.