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Abstract
The insecticide susceptibility in cat flea adult and larvae, Ctenocephalides
felis (Bouch(), were examined in this experiment. The LC50s of cypermethrin,
cyfluthrin, carbaryl, propoxur, fenthion, and chlorpyrifos to adult cat flea
were 26.989 ug/cm2, 18.860 ug/cm2, 1.708 ug/cm2, 1.783 ug/cm2, 0.494 ug/cm2,
0.185 ug/cm2 respectively. The LC50s of fenthion, and chlorpyrifos, cyfluthrin,
and cypermethrin, to cat flea larvae were 0.411 ug/cm2, 1.802 ug/cm2, 2.562
ug/cm2, 2.968 ug/cm2, respectively. Carbaryl and
propoxur was unachievable in 50 % mortality in cat flea larvae even at the
highest concentration treatment.
The esterase in cat flea larvae showed the highest specific activities
at pH 7.5. The specific activities of esterase were temperature dependent,
the higher temperature the higher activity. But the reasonable
physical reaction
temperature should be at 27 0C. The enzyme concentration in the
reaction mixture
between 0.08-1 individual /ml gave the similar specific enzymatic activity. The
incubation period of reaction time between 5-30 minutes made no
different in the
specific enzymatic activity. The esterase specific activity in 10 days old 3rd
instar larvae had the highest activity and the 6 days old 3rd instar larvae had
the lowest activity. In the 12 days old 3rd instar larvae also had the lower
activity since the pupation proceeded.
The components of esterase activity in cat flea larvae, carboxylesterase,
cholinesterase and arylesterase, were 61.92 %, 28.08 % and
10.00 %, respectively.
The specific activities of esterase in cat flea larvae were suppressed by
by contacting to chlorpyrifos, propoxur and carbaryl. There were no significant
effects on enzymatic activity distribution in individual larva
after cyfluthrin,
cypermethrin, fenthion and chlorpyrifos treatment. But after treated propoxur
and carbaryl inhibited the esterase activity.
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