The potential of Pseudapanteles dignus to control T. absoluta in Argentina.

LUNA, M.G.; SALAS GERVASSIO N. G. ; SÁNCHEZ, N.E.

Pucón

Congreso; IV International Symposium on biological control of arthropods (ISBCA).; 2013

Universidad Pontificia de Chile

The tomato moth, Tuta absoluta (Lepidoptera: Gelechiidae), is a key tomato pest originated from South America. After its introduction into Europe in 2006, it spread across Afro-Euroasia, threatening major tomato producing countries, as India and China. Although it has not been reported in North America yet, it is considered as an emergency pest (Desneux et al. 2011). In Argentina, T. absoluta management is mainly based on preventive weekly or bi-weekly applications using about 16 different neurotoxic insecticides (Sánchez et al. 2009). Chemical control costs can reach up to 38% ($175 US per ha per crop cycle) of total sanitary costs. After hatching, young T. absoluta larvae enter into tomato fruits, leaves or stems, on which they feed and develop, thus creating conspicuous mines. Potato, eggplant, tobacco and wild solanaceous species are also reported as hosts of T. absoluta (Pereyra and Sánchez 2006). Biological control of T. absoluta is regarded as feasible because there are over 50 species of predators and parasitoids reported throughout the actual pest distribution (Luna et al. 2012). Indeed, T. absoluta biological control is commercially available in some countries in Europe and South America by means of augmentative releases of egg and larval parasitoids, and hemipteran predators. In Argentina, despite an increasing interest by producers, biological control remains as an agronomic tool to be developed for this pest (Luna et al. 2007; Pereyra et al. 2010). Our studies aimed at promoting T. absoluta biological control by using entomophagous insects naturally occurring in the local tomato agro-ecosystem by bringing producers an efficient, low-cost and environmentally safe pest management. We present results on: 1) life history traits of two main T. absoluta larval parasitoid wasps, the endoparasitoid Pseudapanteles dignus (Hymenoptera: Braconidae) and the ectoparasitoid Dineulophus phtorimaeae (Hymenoptera: Eulophidae), 2) their patterns of parasitism in the field, 3) preliminary evaluations of the effectiveness of P. dignus inoculative releases on T. absoluta control in an experimental tomato greenhouse, and 4) exploration of P. dignus and T. absoluta alternative hosts (other gelechiids, and cultivated vs. natural vegetation) as baseline information to determine the risks of implementing tomato leafminer biological control. Research was conducted in commercial tomato farms of Northern Buenos Aires province, Argentina. Collaborative work was also done along with INTA.