Biology, distribution and damage of Tuta absoluta, an exotic invasive pest from South America

Tuta absoluta (Meyrick) is an invasive pest of tomato native to South America, where it is responsible for extensive damage. In Europe it was first detected in Spain in 2006 and afterwards it rapidly spread into several countries becoming a key pest due to its behaviour and ecology, to the absence of co-evolved biocontrol agents and to the reduced knowledge of its control. After only five years from its first record in the Old World, the moth is currently present in Portugal (including Azores), Spain (including Canary Islands), France, Switzerland, Italy, UK, the Netherlands, Germany, Lithuania, Bulgaria, South West Russia, Hungary, Kossovo, Albania, Greece, Cyprus, Turkey, Iraq, Lebanon, Israel, Jordan, The Gaza strip, Morocco, Algeria, Tunisia, Saudi Arabia and Libya. The extraordinary spreading process of the species could be attributed not only to its dispersal capacity but mainly to the intensive international tomato commercialization. The moth can secondarily feed on other solanaceous species, both cultivated (such as potatoes, eggplant and sweet pepper), and wild (species of the genera Solanum, Datura, Nicotiana and Lycium) as well as on some non-solanaceous plants. This capability to use alternative plants as secondary hosts advantages the continuous presence of this pest in many habitats, also in absence of tomato crops. The knowledge of the main biological traits of the pest is the base to develop effective plant protection management strategies. T. absoluta is a multivoltine species with an homodynamous behaviour and the length of its life-cycle depends on environmental conditions, particularly temperature. The larvae feed and develop inside tomato leaves, stems and fruits throughout the entire growing cycle. Mature larvae pupate in sheltered sites usually in the soil making control more difficult. The adults have nocturnal habits and in Mediterranean conditions they can be easily detected all over the year. Damage is directly related to the reduction of the photosynthetic capacity and of the production levels, both in protected and open-field tomato crops; besides, economic loss derives from the unmarketability of the infested fruits whose presence makes post-harvest processes (packing, storage and shipment) more expensive. Indirect damage can be also caused by secondary infection of pathogens developing on the infested plant and fruit tissues. Finally, the persistence of the pest inside tomato fruit together with its resistance to low temperatures can strongly interfere with exportation flows to the countries were T. absoluta is still not present; this capacity strongly fosters its invasive behaviour.