Effect of the olive fruit size on the parasitism rates ofBactocera oleae(Diptera: Tephritidae) by the figitid waspAganaspis daci(Hymenoptera: Figitidae), and first field releases of adult parasitoids in olive grove

Abstract

<jats:title>Summary</jats:title><jats:p>The olive fruit fly <jats:italic>Bactrocera oleae</jats:italic> (Rossi) (Diptera: Tephritidae) is the major pest of olives worldwide. The figitid wasp, <jats:italic>Aganaspis daci</jats:italic> (Hymenoptera: Figitidae), is a larval-prepupal endoparasitoid of fruit fly species, and it was found to successfully parasitize medfly larvae in field-infested figs in Greece. To assess the potential of <jats:italic>A. daci</jats:italic> as a biological control agent against <jats:italic>B. oleae</jats:italic>, we studied the effect of olive fruit size on parasitism rates of <jats:italic>A. daci</jats:italic> on 2<jats:sup>nd</jats:sup> and 3<jats:sup>rd</jats:sup> instar larvae of <jats:italic>B. oleae</jats:italic>, by using fruit of different size (cultivar ‘Chalkidikis’) and wild olive fruit. In addition, we conducted releases of <jats:italic>A. daci</jats:italic> females in a pilot olive grove in Volos, Magnesia. From July to October, we released 200 <jats:italic>A. daci</jats:italic> females/0.1 ha/week, followed by olive fruit sampling to estimate olive fruit infestation levels and the parasitism rates of <jats:italic>A. daci</jats:italic>. Laboratory trials revealed that fruit size and larvae instar were predictors of parasitism success of <jats:italic>A. daci</jats:italic>, with parasitism rates higher for small-size fruit of the cultivar “Chalkidikis” and the 3<jats:sup>rd</jats:sup> instar larvae of <jats:italic>B. oleae</jats:italic>. In field trials, no <jats:italic>A. daci</jats:italic> adults emerged from the olive fly infested fruit.</jats:p>

A Minor Role of Host Fruit on the Parasitic Performance of Aganaspis daci (Hymenoptera: Figitidae) on Medfly Larvae

“…Laboratory and greenhouse trials confirmed that A. daci could parasitize tephritid larvae on different host fruits, supporting previous observations. This species had been previously observed parasitizing larvae from the genus Bactrocera Macquart on mango and cempedak in its area of origin [ 9 ], on guava in Egypt [ 15 ], and even on olive fruits in laboratory trials in Greece [ 58 ]. Moreover, A. daci has been reported emerging from larvae of C. capitata on figs [ 18 , 20 ], citrus [ 20 ], apples [ 59 , 60 ], loquats, guavas, grapefruits, and peaches [ 21 , 22 ].…”