Abstract:
To evaluate the safety of different insecticides to two parasitoids
Encarsia formosa and
Encarsia sophia of
Bemisia tabaci, and to provide scientific basis for integrated pest management and rational application of insecticides in
B. tabaci control, laboratory toxicity of different insecticides on
E. formosa and
E. sophia was determined by residual film in glass tube method. Meanwhile, the risk of
E. formosa and
E. sophia was evaluated in laboratory conditions. The results showed that 22.4% spirotetramat showed the lowest laboratory toxicities on
E. formosa and
E. sophia during in all of the tested insecticides, with the LC
50 being 136.465 mg/L and 119.408 mg/L, respectively. The highest laboratory toxicities to both of this two parasitoids were from 20% dinotefuran among in all of the tested insecticides, with the LC
50 being 14.496 mg/L against
E. formosa and 9.259 mg/L against
E. sophia, respectively. The LC
50 of different kinds of tested insecticides against
E. formosa were higher than that against
E. sophia. Among which, 22.4% spirotetramat and 50% sulfoxaflor showed medium risk against both
E. formosa and
E. sophia, 10% nitenpyram, 10% cyantraniliprole and 20% dinotefuran showed high risk to the two parasitoids. 22.4% spirotetramat and 50% sulfoxaflor showed medium risk on
E. formosa and
E. sophia. The concentration of insecticides and the times of application should be properly reduced on the premise of ensuring the control effect when it was used to control
B. tabaci in the field. Meanwhile, the application of these insecticides should be avoided to use during the peak period of adult parasitoid emergence. 10% nitenpyram, 10% cyantraniliprole and 20% dinotefuran had higher risk than the other two insecticides on
E. formosa and
E. sophia, which should be avoided to use during the active period of
E. formosa and
E. sophia in
B. tabaci control.
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