Experimental releases of Anthocoris nemoralis F. and Anthocoris nemorum (L.) (Heteroptera: Anthocoridae) against the pear psyllid Cacopsylla pyri L. (Homoptera: Psyllidae) in pear

We investigated the potential for control of pear psyllid, Cacopsylla pyri in pear orchards by Anthocoris nemoralis and Anthocoris nemorum in semi-field and field experiments. One adult A. nemorum or A. nemoralis female reduced C. pyri eggs and young nymphs in sleeve cages by almost a third and by half respectively after two days in an experimental infestation. In a natural infestation two A. nemorum, two A. nemoralis or both together reduced C. pyri eggs and nymphs by 72–90% compared to a control in two weeks. In a small field experiment, 5–6% of introduced C. pyri remained on branches where A. nemoralis eggs had been laid, while twice as many remained on untreated branches, reflecting a significant effect of anthocorids but also considerable natural mortality. Field releases of 10 or 30 A. nemoralis nymphs per tree in three orchards in early May and again two weeks later resulted in reductions of 31–40% in C. pyri with one exception: in the orchard that had the initially highest psyllid infestation, the treatment with releases of only 10 A. nemoralis nymphs was not significantly different from the control. In general, adult anthocorids as well as nymphs brought about considerable reductions in pest numbers. Field releases show promise for developing a practical release method.