Natural enemies associated with Tuta absoluta and functional biodiversity in vegetable crops

Tuta absoluta Meyrick (Lepidoptera: Gelechiidae) is considered one of the main pests threatening tomato production worldwide. In the Mediterranean, the use of predatory mirids is widespread, and although several larval parasitoid species have been recorded in the area, their contribution to the biological control of the pest is often neglected. With the general objective of improving the biological control of T. absoluta, our field study aimed to determine the relative abundance of natural enemies associated with T. absoluta in tomato fields and to assess whether insectary plants placed in the vicinity of vegetable crops would help to improve functional biodiversity in the farms. The study was conducted during two years in six commercial tomato fields in Northeast Spain that were managed using an integrated pest management program based on predatory mirid conservation. Our results indicated that Necremnus tutae Ribes & Bernardo (Hymenoptera: Eulophidae) was by far the main natural enemy responsible for larval parasitism of T. absoluta. The flowering plants used in the present study were attractive to several natural enemies that are of interest not only for tomato but also for other vegetable crops coexisting at the farm level, including parasitoid wasps, hoverflies, and other important beneficials, such as Orius spp., ladybeetles and predatory thrips.