Evaluation of native larval parasitoids as biological control agents against T. absoluta in Argentina

LUNA, M. G.; PEREYRA, P.C.; SANCHEZ, NE

Pucón

Simposio; IV International Symposium on biological control of arthropods (ISBCA). Session: ?Evaluation and practical application of parasitoids and predators of the tomato borer Tuta absoluta?; 2013

Universidad Católica 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 has been spreading 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). Particularly in Argentina, the leafminer 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% (US $175 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 & Sánchez 2006). Biological control of T. absoluta is regarded as a feasible technique because there are over 50 species of predators and parasitoids reported throughout the actual pest distribution (Luna et al. 2012). Indeed, T. absoluta biocontrol is commercially available in some countries in Europe and South America by means of augmentative releases of egg and larval parasitoids, and hemipteran predators; meanwhile 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 are focused to promote T. absoluta biological control by using entomophagous insects naturally occurring in the local tomato agro-ecosystem. The aim is to bring producers an efficient, low-cost and environmentally safe pest management. We present results on: a) life history traits of two main T. absoluta larval parasitoid wasps, the endoparasitoid Pseudapanteles dignus (Hymenoptera: Braconidae) and the ectoparasitoid Dineulophus phtorimaeae (Hymenoptera: Eulophidae), b) their patterns of parasitism in the field, c) preliminary evaluations of the effectiveness of P. dignus inoculative releases on T. absoluta control in an experimental tomato greenhouse, and d) 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 is conducted in commercial tomato farms of Northern Buenos Aires province, Argentina. Collaborative work is also done along with INTA.