title: Toxicity of pyrethroids and repellency of diethyltoluamide in two deltamethrin-resistant colonies of Triatoma infestans Klug, 1834 (Hemiptera: Reduviidae).
abstract: The aim of the currrent investigation was to evaluate (a) the toxicity of three pyrethroids (deltamethrin, lambda-cyhalothrin, and tetramethrin); (b) the effect of these insecticides on the locomotor activity; and (c) the repellent effect of N,N-diethyl-m-toluamide (DEET) on two deltamethrin-resistant strains of Triatoma infestans from Argentina (El Chorro and La Toma), and one susceptible strain. The resistance ratios (RRs) obtained for the La Toma strain were: > 10,769, 50.7, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The RRs for the El Chorro strain were: > 10,769, 85.8, and > 5.2 for deltamethrin, lambda-cyhalothrin, and tetramethrin respectively. The hyperactivity usually caused by the three pyrethroids was in both the deltamethrin-resistant strains compared to the susceptible reference strain. No differences were observed in the repellent effect of DEET between the three groups. These results indicate that the deltamethrin-resistant insects have a cross resistance to lambda-cyhalothrin and tetramethrin, and are also resistant to the first symptom of pyrethroid poisoning (hyperactivity). However, the sensorial process related to DEET repellency does not appear to be altered.
authors.affiliation: Centro de Investigaciones de Plagas e Insecticidas, Villa Martelli, Provincia de Buenos Aires, Argentina.
authors.forename: Valeria
authors.initials: V
authors.lastname: Sfara
authors.forename: Eduardo N
authors.initials: EN
authors.lastname: Zerba
authors.forename: Raúl A
authors.initials: RA
authors.lastname: Alzogaray
mesh_terms: D000818:Animals; D003671:DEET; D007302:Insect Repellents; D007306:Insecticides / Q000633:toxicity*; D007928:Lethal Dose 50; D009043:Motor Activity / Q000187:drug effects*; D009758:Nymph / Q000187:drug effects; D011722:Pyrethrins / Q000633:toxicity*; D014224:Triatoma
chemical_list: D007302:Insect Repellents; D007306:Insecticides; D011722:Pyrethrins; D003671:DEET