Is Harmonia axyridis a potential biocontrol agent in Christmas tree plantations?

Abstract: Nordmann fir (Abies nordmanniana) Christmas trees are a high value crop and qualitydemands are high. The adelgid Dreyfusia nordmannianae is the key pest in the production ofChristmas trees, feeding on current-year foliage and causing needle distortion. Laboratory assayswere carried out to evaluate the potential of Harmonia axyridis as a biocontrol agent in Christmastree plantations. Differences appeared in the predation efficiency of larvae and adults as well as inthe suitability as prey of different adelgid generations and developmental stages. Harmoniaaxyridis preferred and performed better on aphids belonging to Aphidoidea than on an adelgiddiet. Our laboratory results indicate that H. axyridis may not be a highly effective biocontrolagent against D. nordmannianae. However, H. axyridis may assist in the natural regulation of theincreasingly common lachnid Cinara confinis in Christmas tree plantations.