White Peach Scale, Pseudaulacaspis pentagona (Targ.) (Hemiptera: Diaspididae), is affected by host plant variety in a blackcurrant orchard

The White Peach Scale (WPS), Pseudaulacaspis pentagona (Hemiptera: Diaspididae) is one of the most damaging armored scale insects as it is a pest of various crops, including ornamental plants and fruit trees. In France, P. pentagona has become one of the main threats towards blackcurrants (Ribes nigrum L.), especially in Burgundy, the Loire Valley and the Rhone-Alpes where the cultivation of blackcurrants is not only an emblematic and cultural activity but also has economic importance. We determined the direct effect of blackcurrant varieties on the infestation rate, female body size, and parasitism rate of P. pentagona. Our study was conducted in a Burgundy (France) natural population of P. pentagona developing on two blackcurrant varieties `Noir de Bourgogne' and `Royal de Naples'. This field study showed that WPS females feeding on `Noir de Bourgogne' were more numerous, had a larger body, a larger shield, and were less parasitized compared to females feeding on `Royal de Naples' at the same site. However, the high scale density and the low parasitism rate found overall on both varieties brings into question the benefits of a pest management strategy based on the change of the varieties used in blackcurrant orchards.