Parasitoid complex associated to Tuta absoluta (Lepidoptera: Gelechiidae) and other leafminers in cultivated and non-cultivated Solanaceae, in Argentina

Knowledge on indigenous natural enemies for a given pest is essential to design biological control strategies, in a suitable and sustainable manner. For parasitoids, host plants can play a key role by providing them refuge and alternative food resources to population growth and sustainability. The general aim of this study is to maximize the action of natural enemies of South American tomato leafminer, Tuta absoluta (Meyrick), with the goal of reducing pesticide use. A two-year field survey was conducted through monthly sampling in cropped –excluding tomato- and spontaneous Solanaceae species in NE Buenos Aires Province, Argentina. The specific objectives were: 1) to assess the host plant range of T. absoluta; 2) to determine the host range of Pseudapanteles dignus (Muesebeck) (Hymenoptera: Braconidae), a major T. absoluta parasitoid in tomato; and 3) to explore the larval parasitoid complex of T. absoluta and other leafminers. A centrifugal phylogenetic approach was employed to select the plant species to be sampled, yielding 3 cultivated and 8 non-cultivated. Plants, leafminer hosts and parasitoids collected were identified and numbers of each were recorded. Graphical phenological profiles were constructed. T. absoluta was found year-round in 1 cultivated and 4 non-cultivated species. Interaction between P. dignus and T. absoluta occurred in 3 plant species. Interestingly, a complex of 17 parasitoid species attacked T. absoluta and other leafminers in 7 solanaceous species surveyed, most of them not reported before in association to this pest in tomato crops at the study region. Parasitism of T. absoluta was also observed throughout the year. This information indicates that other host plants than tomato maintain a natural parasitoid complex of T. absoluta when the crop is absent in the region.