In 2009, the sensitivity of 15 field populations of Colorado potato beetle
(Leptinotarsa decemlineata Say.) - CPB was assessed to chlorpyrifos,
cypermethrin, thiamethoxam and fipronil, four insecticides which are mostly
used for its control in Serbia. Screening test that allows rapid assessment
of sensitivity of overwintered adults to insecticides was performed.
Insecticides were applied at label rates, and two, five and 10 fold higher
rates by soaking method (5 sec). Mortality was assessed after 72h. From 15
monitored populations of CPB, two were sensitive to label rate of
chlorpyrifos, one was slightly resistant, 11 were resistant and one
population was highly resistant. Concerning cypermethrin, two populations
were sensitive, two slightly resistant, five were resistant and six highly
resistant. Highly sensitive to thiamethoxam label rate were 12 populations,
while three were sensitive. In the case of fipronil applied at label rate,
two populations were highly sensitive, six sensitive, one slightly resistant
and six were resistant. The application of insecticides at higher rates (2, 5
and 10 fold), that is justified only in bioassays, provided a rapid insight
into sensitivity of field populations of CPB to insecticides.
Screening test for detection of Leptinotarsa decemlineata (Say) sensitivity to insecticides