Ooctonus vulgatus(Hymenoptera, Mymaridae), a potential biocontrol agent to reduce populations ofPhilaenus spumarius(Hemiptera, Aphrophoridae) the main vector ofXylella fastidiosain Europe

Abstract

As a vector ofXylella fastidiosa(Wells, 1987) in Europe, the meadow spittlebugPhilaenus spumarius(Linnaeus, 1758) (Hemiptera, Aphrophoridae) is a species of major concern. Therefore, tools and agents to control this ubiquitous insect that develops and feeds on hundreds of plant species are wanted. We conducted a field survey ofP. spumariuseggs in Corsica and provide a first report ofOoctonus vulgatusHaliday, 1833 (Hymenoptera, Mymaridae) as a potential biocontrol agent ofP. spumariusin Europe. To allow species identification, we summarized the main characters distinguishingO. vulgatusfrom other European species ofOoctonusand generatedCOIDNA barcodes. Parasitism rates were variable in the four localities included in the survey but could reach 69% (for an average number of eggs that hatched per locality of 109). Based on the geographic occurrences ofO. vulgatusobtained from the literature, we calibrated an ecological niche model to assess its potential distribution in the Holarctic. Obviously, several questions need to be addressed to determine whetherO. vulgatuscould become an effective biocontrol agent ofP. spumariusin Europe. So far,O. vulgatushas been reared only fromP. spumariuseggs, but its exact host-range should be evaluated to ensure efficiency and avoid non-target effect. The top-down impact of the parasitoid on vector populations should also be assessed on large data sets. Finally, the feasibility of mass rearing should be tested. We hope this report serves as a starting point to initiate research on this parasitoid wasp to assess whether it could contribute to reduce the spread and impact ofX. fastidiosain Europe.