A mycoinsecticide combined into pheromone-containing traps builds a valuable strategy against Chagas disease vectors in Argentina”. (Comunicación oral).

JUÁREZ M PATRICIA; FORLANI LUCAS; PEDRINI NICOLAS; GIROTTI JUAN R.; MIJAILOVSKY SERGIO J

Greenwich

Congreso; Ento'11. Royal Entomological Society's Annual National Meeting e International Symposium on Chemical Ecology: Reception, Detection and Deception.; 2011

Royal Entomological Society

Triatomine kissing bugs mediate the transmisión of Tripanosoma cruzi, the causative agent of Chagas disease, the most relevant parasitic disease in Latin America. Current control strategies based on insecticide spraying, are growingly threatened by the emergence of pyrethroid-resistant bug populations. We have already shown that entomopathogenic fungi have the ability to breach the insect cuticle and are effective both against pyrethroid-susceptible and resistant Triatoma infestans bugs, either in laboratory or field assays [1]. We also know that T. infestans cuticle lipids play a major role as contact aggregation pheromones. Here we will discuss the potential of pheromone–based infection traps to effectively kill bugs indoors. A powdered Beauveria bassiana formulation (GHA, Laverlam, USA) was placed in traps containing the cuticle pheromone. Different formulations and doses of fungal formulation were tested. In laboratory assays, insects were released within the traps for a short period; then, they were maintained individually and mortality was checked daily. Field assays were performed in rural houses in the Argentina-Bolivia border. Traps were fixed on the walls close to the insect refuges detected; they were replaced after a month. All traps were removed after an additional month. Insects were counted before and after treatment, and fungal infection was checked on dead bugs. When insects were released into pheromone-containing traps, 42.5 ± 16.4% of the bugs were aggregated after 4 h; the response increased significantly (87.9 ± 10.2%, P < 0.05) 24 h after starting the assay. When the fungal formulation was incorporated into the traps, mortality was significantly different (P < 0.05) in the presence (59.0 ± 9.6%), or absence (33.3 ± 5.3%) of the pheromone. In field assays, 59.3 ± 9.5 % of the total bugs detected were killed by the fungi after 2 months. The cumulative mortality due to fungal infection from November to January, compared to the initial number of insects detected before intervention, was 84.2 ± 11.3 %. This low cost, low tech, ecologically friendly methodology is the first proven alternative to help control T. infestans, regardless their pyrethroid susceptibility.   [1] Pedrini N. et al., PLoS Negl Trop Dis 3(5): e434