Species Diversity in the Parasitoid Genus Asobara (Hymenoptera: Braconidae) from the Native Area of the Fruit Fly Pest Drosophila suzukii (Diptera: Drosophilidae)

Abstract

Drosophila suzukii (Matsumura), commonly known as Spotted Wing Drosophila (SWD), is a worldwide serious economic threat to the production of berries and stone fruits. The chemical control widely used against this pest is often not able to preventing yield losses because wild flora offers an abundance of fruits to D. suzukii where the pest is able to reproduce and from where it recolonizes neighbouring cultivated fields. Alternatively, within Integrated Pest Management protocols for D. suzukii, biological control could play a key role by reducing its populations particularly in non-cultivated habitats, thus increasing the effectiveness and reducing the side negative effects of other management strategies. Because of the scarcity and of the low efficiency of autochthonous parasitoids in the new invaded territories, in the last few years, a number of surveys started in the native area of D. suzukii to find parasitoid species to be evaluated in quarantine structures and eventually released in the field, following a classical biological control approach. This paper reports the results of these surveys carried out in South Korea and for the first time in China. Among the parasitoids collected, those belonging to the genus Asobara Foerster resulted dominant both by number and species diversity. By combining morphological characters and the mitochondrial COI gene as a molecular marker, we identified seven species of Asobara, of which two associated with D. suzukii, namely A. japonica and A leveri, and five new to science, namely Asobara brevicauda, A. elongata, A mesocauda, A unicolorata, A. triangulata. Our findings offer new opportunity to find effective parasitoids to be introduced in classical biological control programmes in the territories recently invaded by D. suzukii.

Host specificity of Asian parasitoids for potential classical biological control of Drosophila suzukii

“…This species was already known as a polyphagous parasitoid in Asia, being recorded on more than 25 Drosophilidae species (Nomano et al 2015). Daane et al (2016) and Guerrieri et al (2016) recorded it on D. suzukii in South Korea and Mitsui and Kimura (2010), Nomano et al (2015) and Matsuura et al (2017) in Japan. Other studies in Europe and North America showed its ability to parasitize D. suzukii by affecting the haemocyte load of larvae, thereby overcoming its cellular immune system (Chabert et al 2012; Kacsoh and Schlenke 2012; Poyet et al 2013).…”

Development of Asian parasitoids in larvae Of Drosophila Suzukii feeding on blueberry and artificial diet

“…Consequently, there is an urgent need to revise the taxonomy of the G. brasiliensis complex as this taxonomic uncertainty may prevent its use for biological control. Asobara japonica and L. japonica are both known to attack D. suzukii and other Drosophila species in Asia Guerrieri, Giorgini, Cascone, Carpenito, & van Achterberg, 2016;Ideo et al, 2008;Mitsui & Kimura, 2010;Novković et al, 2011;Wachi, Nomano, Mitsui, Kasuya, & Kimura, 2015), but for these species too, the occurrence of biotypes or cryptic species, potentially showing different levels of host specificity, should be further investigated. Host range tests are currently underway with these Asian parasitoids and European Drosophila spp.…”

Environmentally sustainable pest control options forDrosophila suzukii

“…In the D. suzukii native range, Asobara japonica and A. leveri develop on D. suzukii larvae (Guerrieri, Giorgini, Cascone, Carpenito, & van Achterberg, ; Ideo, Watada, Mitsui, & Kimura, ). Furthermore, in a survey of eight native Asobara spp.…”

“…There may be additional unknown Leptopilina and Asobara spp. that could be useful control agents for D. suzukii , as indicated by a recent field study, which described five new species of Asobara (Guerrieri et al., ).…”