Differences of susceptibility of five triatomine species to pyrethroid insecticides - Implications for Chagas disease vector control

As pyrethroids are presently the favored group of insecticides to control t riatomines, we performed a series of bioassays to determine the intrinsic a ctivity of some of the main compounds used in the control campaigns, agains t five of the main species of triatomines to be controlled Comparing the insecticides it can be seen that lambdacyhalothrin is more ef fective than the other three pyrethroids, both considering the LD50 and 99 for all the three species with comparable results. On Triatoma infestans th e LD50 of lambdacyhalothrin was followed by that of alfacypermethrin, cyflu thrin and deltamethrin. On Rhodnius prolixus the sequence, in decreasing or der of activity, was lambdacyhalothrin alfacypermethrin, deltamethrin and c yfluthrin. Some modifications can be seen when we compare the LD99, that ha s more to see to what happens in the field. T. brasiliensis showed to be as sensible to lambdacyhalothrin as T. infestans, the most susceptible for th is product. By the other side T. sordida is the least susceptible consideri ng the LD99 of this insecticide.