Cacopsylla pruni (Hemiptera, Psyllidae) in an apricot orchard is more attracted to white sticky traps dependent on host phenology

Abstract

The colour preference of the plum psyllid,Cacopsylla pruni(Hemiptera, Psyllidae), is yet poorly studied. This species is the only known vector of the ‘CandidatusPhytoplasma prunorum’, the agent of European stone fruit yellows (ESFY), a devastating disease of several cultivatedPrunusspecies in Europe. As ESFY is still uncurable, vector control, thus vector monitoring, is pivotal to protect these trees.Cacopsylla pruniis a univoltine, host-shelter-alternating species; overwintered adults migrate from conifer to wild or cultivatedPrunusspecies (family Rosaceae) in late winter-early spring. To select the most effective colour indicating the arrivals of the immigrants, yellow, fluorescent yellow, white, red and transparent sticky traps were deployed in an apricot orchard in Hungary. The two most abundant species in sticky traps wereC. pruniandC. melanoneura. Catches of white traps were significantly biased towardsC. prunias compared toC. melanoneuraspecimens. Moreover, white sticky traps were better at catching plum psyllids than the other colours. Attraction to white was strongest when immigrants from shelter plants kept arriving in the orchard, coinciding with the blooming principal phenophase of apricot trees. When the host flowering growth stage was over, catches ofC. pruniin white traps declined sharply to the level of yellow traps that was highest during this post-blooming period. We recommended white sticky traps for promptly monitoringC. pruniin apricot orchards because it is more potent and more selective than yellow ones during the critically important early flowering interval.