INVESTIGADORES
MASUH Hector Mario
artículos
Título:
New spot-on formulation containing chlorpyrifos for controlling horn flies on cattle: laboratory model of insecticide release and field trial
Autor/es:
LAURA JUAN; EDUARDO ZERBA; PEDRO MARIATEGUI; CLAUDIO SPEICYS; GUILLERMO TARELLI; SEBASTIÁN DEMYDA; HÉCTOR MASUH
Revista:
PARASITOLOGY RESEARCH
Editorial:
SPRINGER
Referencias:
Año: 2010 vol. 107 p. 967 - 974
ISSN:
0932-0113
Resumen:
A highly viscous formulation containing chlorpyrifos
(RET) was evaluated under laboratory, pre-field, and field
conditions, and compared against ear tags with organophosphorus
insecticides. Laboratory bioassays were performed
using Musca domestica L. and a thin layer chromatography
(TLC) plate of reversed phase silica gel modeling a lipophilic
surface. Insects were exposed to the insecticide vapors of
both formulations, directly and indirectly to test for lateral
diffusion. Knockdown time 50% (KT50) values were
determined as toxicological indicators of insecticide release.
Minimum KT50 values of the direct effect of both formulations
on horn flies were reached 4 weeks after being applied.
The KT50 effect of migrated insecticides showed that RET
formulation had a maximal effectiveness between the fourth
and tenth last week. The KT50 effect of the insecticide
migrating from ear tags decreased during the last 2 weeks of
the experiment, and the KT50 effect of the laterally migrated
insecticide was significantly higher for the RET formulation
during this period. A pre-field bioassay was performed by
exposing pieces of rabbit leather with both formulations and
recording the KT50. At the end of the experiment, the KT50
effect of laterally migrated insecticide was significantly
higher for the RET formulation. Regarding vapor emission,
as a general trend the KT50 effect of ear tags was greater than
for the RET formulation. To evaluate the horn fly infestation
in the field bioassays, photographs of the animal were taken.
The results shows that RET provided significant control for
11 weeks while the ear tags provided protection until the
12th week.