A study of the effects of imidacloprid under laboratory and field conditions on nymphs of Triatoma infestants (Hemiptera: Reduviidae)

SILVESTRINI, MARÍA P.; MESTORINO, NORA; DADÉ, MARTÍN M.; BOZZOLO, FACUNDO; DANIELE, MARTÍN R.; FRANCINI, FLAVIO

VETERINARY PARASITOLOGY

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2020 vol. 280

0304-4017

The aim of this study was to determine imidacloprid´s lethalactivity in fifth-instar nymphs of Triatoma infestants. In the firststage of the current work, a topical application assay of the insecticideon non-fed and repletion-fed nymphs was performed. The results showed aDL50 three times greater in non-fed bugs than in those fully engorged.The presence of food determined less time for the maximum lethal effectof the insecticide: 24 h post topical application for fed nymphs and 72 hfor non-fed nymphs. In the second stage of this study, a xenointoxicationassay on dogs was performed. The commercial products, Advantage®, Bayer(imidacloprid 10% p/v) and Power Ultra®, Brouwer (imidacloprid 5.15%,permethrin 40% and piperonyl butoxide [PBO] 3%) were evaluated. Once theinsecticide was administered, nymphs were fed on dogs 24, 72, 168, 240and 336 h post-administration. Blood intake was similar among nymphsexposed to treated dogs compared to control groups. Although bothcommercial products showed a low triatomicidal activity, a higherefficacy of the product combining imidacloprid with the synergistpiperonyl butoxide and permethrin compared to the product withimidacloprid as the only active ingredient was observed. The resultssuggest that imidacloprid alone or in combination with permethrin and PBOdo not represent an alternative for the control of T. infestans.