Hymenoptera parasitoid complex of Prays oleae (Bernard)(Lepidoptera: Praydidae) in Portugal

Abstract

The olive moth, Prays oleae (Bernard) (Lepidoptera: Praydidae), is one of the most important pests of olive trees throughout the Mediterranean region, the Black Sea, the Middle East, and the Canary Islands. Thus, it is particularly important to develop alternative strategies to control this pest. Over a 4-year period, a survey was done in order to acquire knowledge about the complex of parasitoids associated with this pest. Leaves, flowers, and fruit infested with larvae and pupae of P. oleae were collected from olive groves, conditioned in vials, and kept under laboratory conditions until the emergence of P. oleae adults or parasitoids. The abundance and richness of parasitoids as well as the rate of parasitism was estimated. Hymenoptera parasitoids were found to be responsible for 43% of the mean mortality of the sampled individuals. From the 22 parasitoid species recorded, three dominated in terms of the provoked parasitism rates: Ageniaspis fuscicollis (Dalman) (Encyrtidae), Chelonus elaeaphilus Silvestri (Braconidae), and Elasmus flabellatus (Fonscolombe) (Elasmidae) (Hymenoptera). Additionally, several of the identified taxa were reported for the first time in Portugal as parasitoids of P. oleae. Moreover, a strong relationship between the species of parasitoids and the generation of the pest was found. Given the moth's presence and its impact on olive tree production worldwide, the outcomes of this study show a rich complex of parasitoids that naturally occurs in association with P. oleae, causing high mortality rates, and highlight the importance of these beneficial parasites in the control of this pest.

Parasitic wasps related to Prays oleae (Bernard, 1788) (Lepidoptera, Praydidae) in olive orchards in Greece

“…Very recently, the hymenopteran parasitoid complex of P. oleae was studied in Portugal where, among the 22 recorded parasitoid taxa, A. xanthostigma was the major natural enemy (Nave et al 2017). Furthermore, in Egypt A. xanthostigma was found to parasitise the larval stage of P. oleae at a rate of more than 50% (Herz et al 2005).…”

“…The subgenus Microchelonus Szepligeti, 1908 is even considered as a valid genus, following the standpoints of Papp (2014a, b). The genus Chelonus Panzer, 1806 counts 601 species in the Holarctic region (Papp 2014c) with M. elaeaphilus being known in the Mediterranean region, either as M. elaeaphilus or C. elaeaphilus (Papp 2012; Nave et al 2017). This species has been introduced and established in Greece from France (Yamvrias 1998).…”

“…Diadegma armillatum is a known parasitoid of various lepidopterous species (Velcheva et al 2012; Fernandez Triana et al 2014) that has been recently recorded attacking P. oleae larvae (Nave et al 2017). The genus Exochus Gravenhorst, 1829 is the largest group of Metopiinae including the widely distributed in Europe, E. lentipes that attacks various Tortricidae and Gelechiidae larvae (Yu et al 2012).…”

“…Prays oleae is one of the main pests infesting olives of commercial production, since larvae of the first, second, and third generations attack flowers, fruits, and leaves, respectively (Kavallieratos et al 2005; Nave et al 2017). The anthophagous generation can cause yield losses up to 581 kg of fruit per ha and the corresponding carpophagous up to 846 kg per ha, an issue that justifies the imposed control measures (Bento et al 2001).…”

“…The anthophagous generation can cause yield losses up to 581 kg of fruit per ha and the corresponding carpophagous up to 846 kg per ha, an issue that justifies the imposed control measures (Bento et al 2001). In recent years, high socioeconomic pressures have forced olive growers to develop alternative control strategies in an effort to mitigate the undesirable side effects of pesticides on trophic chains and biological balances (Nave et al 2017). In this sense, not only the economic losses due to the pest should be evaluated, but also the possible secondary effects that such control measures can have on beneficial fauna (Ramos et al 1998).…”