Effectiveness of inundative releases of Anthocoris nemoralis (Hemiptera: Anthocoridae) in controlling the olive psyllid Euphyllura olivina (Hemiptera: Psyllidae)

This study investigated the effectiveness of field releases of nymphs of Anthocoris nemoralis (F.) (Hemiptera: Anthocoridae) in controlling the olive psyllid, Euphyllura olivina Costa (Hemiptera: Psyllidae). Field trials were conducted in two successive years (2014 and 2015) in two organic olive orchards located in the region of Sfax (Tunisia) using two treatments: low (release of 10 A. nemoralis nymphs/tree) and high (release of 40 A. nemoralis nymphs/tree) applied two times, the first on March 3 and second on March 17. In both olive orchards, the high treatment was the most effective in controlling the increase of E. olivina in the spring. The A. nemoralis population grew gradually and reached a single peak towards the end of April. In control and low treatment plots, despite the significant increase in predator populations, psylla abundance was not controlled. After the second release, however, in high treatment plots a reduction in psyllid density was recorded. An expected effect of the A. nemoralis releases was a reduced parasitic activity of Psyllaephagus euphyllurae (Masi) (Hymenoptera: Encyrtidae).