Survey on indigenous parasitoids of the invasive exotic pest Tuta absoluta in Southern Italy

Abstract: The tomato borer, Tuta absoluta, is an invasive pest native to South-America and sinceits arrival in Europe the tomato production has faced severe yield loss. The composition of theindigenous parasitoid complex of the leafminer was monitored in Southern Italy (Campania,Sardinia and Sicily) during 2009-2011. The parasitoid collection was carried out by exposingsentinel tomato infested plants and by sampling open field and protected greenhouse crops, aswell as Solanum nigrum, a T. absoluta wild host. The parasitoids found developing on theleafminer were mostly generalist idiobionts belonging to 12 genera and 6 families (Ichneumonidae,Braconidae, Eulophidae, Elasmidae, Pteromalidae and Trichogrammatidae). A promptshift of native parasitoids to the new invasive host was observed and the parasitoid complexrecovered on T. absoluta seems to follow the typical pattern of parasitisation on exotic pests,being characterized by a relatively low number of species mostly represented by generalistidiobionts, performing low levels of parasitisation in open field. This study highlighted thesuitability of sentinel plants for indigenous parasitoids surveys in case of heavily treated crops,since the majority of the species were collected on sentinel plants (16 out of 23 totallyrecovered). The data recorded up to now lead to be rather optimistic with reference to theperspective of T. absoluta natural biocontrol in the Mediterranean basin.