Effects of carrot psyllid (Trioza apicalis) feeding on carrot yield and content of sugars and phenolic compounds

Abstract

Carrot psyllid, Trioza apicalis, is a serious pest of carrot in Northern Europe, as it can significantly damage young carrot seedlings in a period as short as 3 days. This study was conducted to investigate effects of carrot psyllid feeding at different plant growth stages on carrot yield and to assess changes in content of sugars, phenolics and related compounds in carrot roots resulting from the psyllid feeding. In addition, reflectance of carrot leaves was measured to assess the intensity of discolouration in damaged leaves. Results showed that carrot yield was significantly reduced by a 3-day carrot psyllid feeding period when the seedlings were exposed to psyllids at 1-or 2-leaf stage. However, at 4-leaf stage feeding by one carrot psyllid did not reduce yield. Sucrose concentration in the damaged roots was significantly decreased, whereas concentrations of some phenolic compounds were significantly increased. The reflectance of leaves of damaged carrots differed significantly from those of undamaged control leaves. These observations indicate that carrot psyllid damage has potential to lower not only the carrot yield, but also the carrot crop quality. No phytoplasma was detected in the carrots exposed to psyllids, but recently, T. apicalis has been associated with 'Candidatus Liberibacter solanacearum'. The role of carrot psyllid feeding and the psyllid-associated bacterium in the damage formation are discussed.A.I. Nissinen et al.Carrot psyllid feeding: yield, sugars and phenolics

Electrophysiological responses of carrot psyllids (Trioza apicalis), in different phases of their life cycle, to volatile carrot and conifer compounds

“…The carrot psyllid, Trioza apicalis (Förster), is a widespread pest of carrots in northern and parts of central Europe and may cause almost complete yield loss (Láska, ; Nissinen et al, ; Rygg, ). Symptoms include reduced and deformed roots and rapid leaf‐curling, which on average becomes visible two days after psyllid feeding (Markkula, Laurema, & Tiittanen, ).…”

Migration flight of carrot psyllid (Trioza apicalis) at various latitudes is independent of local phenology

“…Nissinen et al (2007) showed that damage to small carrot seedlings exposed to just one individual of T. apicalis for only three days led to a significant yield reduction. Later Nissinen et al (2012) found changes in the quality of the roots by attacked plants. The possible participation of Liberibacter on this reduction was discussed by Munyaneza et al (2010).…”

Vector mediated transmission of Candidatus Liberibacter solanacearum and epidemiological consequences

“…Furthermore, direct psyllid feeding could also produce symptoms such as leaf yellowing, leaf distortion and root reduction (Nissinen et al, 2007(Nissinen et al, , 2012. However, the most important damage associated with psyllids is the indirect damage produced by the transmission of plant pathogens.…”

“…Groups of eight individuals from each sex were collected and placed in Eppendorf tubes just before the transmission test was conducted. Each group of 8 psyllids was released onto a 1-leaf stage carrot receptor seedling by opening and inserting the Eppendorf tube into the soil next to the carrot plant, which was then enclosed in a transparent plastic cylindrical cage following a procedure similar to the one described by Nissinen et al (2012). Psyllids started to leave 43 the Eppendorf almost immediately after opening the lid and were able to access and remain on the test plant for 6-h IAP.…”