Pear psylla (Cacopsylla pyri) is a major pest in Swiss pear orchards, causing significant economic losses through the consequences of sap sucking on buds, shoots and leaves. Infestations can lead to reduced plant vigour and fruit size and honeydew accumulation on leaves and fruits. Traditional management relies on plant protection products, but growing concerns about pesticide resistance, environmental impact, and regulatory restrictions have intensified the search for sustainable alternatives. Predatory bugs, such as Anthocoris nemoralis, are biological control agents against pear psylla. We investigate whether A. nemoralis can effectively suppress psylla populations when released in sufficient numbers in a pear orchard in Eastern Switzerland. To evaluate the efficacy of A. nemoralis releases in commercial pear production, a field trial was conducted in a ‘Conference’ pear orchard in 2024 and 2025. Four treatments were compared: (1) Untreated control (no plant protection product and no predator release against pear psylla), (2) Standard chemical plant protection (one application of Spirotetramat against pear psylla), (3) Anthocoris release (release of 2000 A. nemoralis adults/ha, four times per season), and (4) Anthocoris release combined with bio-insecticide treatment (release of 2000 A. nemoralis/ha, four times per season, combined with applications of potassium hydrogen carbonate). We assessed pest and predator population dynamics over the course of the season, plant growth and fruit quality. Results from this trial will provide useful information of the potential of A. nemoralis releases for pear psylla control. Integrating biological control with other non-synthetic measures may further enhance pest management outcomes and reduce reliance on synthetic pesticides.
