Endocrine Disruption Effect Of Insecticides For Control On Diamondback Moth, Plutella Xylostella (Linn.)

By means of High-Performed Liquid Chromatography(HPLC), the dynamics of juvenile hormone (JH) and molting hormone (MH) in larval stages of diamondback moth (DBM), Plutella xylostella (Linn.), were studied. Also, the effect of fipronil, chlorpyrifos, chlorfuazuron and Bt., which were widely used in DBM control in China, on JH and MH expression in DBM was studied to find their endocrine disruption possibility.1 Detection rrocedure for hormone in DBM with HPLCThe detection rrocedure for JH in DBM was set up as, mixture of methanol and water (V:V=70:30) as mobile phase and flowing rate at 1 mL/min, wavelength at 218nm, injection volume 10μL and colomn temperature 35℃and that for MH was mixture of methanol and water (V:V=50:50) as mobile phase and flowing rate at 0.5 mL/min, wavelength at 254nm, injection volume 10μL and colomn temperature 35℃.2 Dynamics of JH and MH in larval stages of DBMEepressed as hormone titer per insect, both JH and MH titer increased with larval stage and a peak could be found within each stage.Juvenile hormone, expressed as the amount in each individual, in the 1st instar larvae was 0.046 ng per insect, and 0.058ng per insect in the 2nd instar larvae and 4.39 ng per insect in the 4th instar larvae. For molting hormone, peaks were also found in the 3rd and 4th instar larvae. The peak was 8.86ng per insect in 3rd instar larave and 21.90ng per insect in 4th instar larvae. The results indicated that the hormone titer per body weight was not a good indicator for hormone dynamic study.3 Effect of insecticide treament on JH and MH in larval stages of diamondback moth (DBM), Plutella xylostella (Linn.)The results indicated that all the tested insecticides, which were fipronil, chlorpyrifos, chlorfluazuron and Bt, could affect the expression of JH or Hormone and resulted in the changes of hormone peak time or hormone titer. But that varied with insecticide types as well as their concentration, hormone type and larval stages.4 Perspective of endocrine disruption of insecticides on DBM controlThe results suggested that many insecticides could disrupt the hormones in DBM and showed a good perspective in DBM control. But to make better use of that, more research work should be conducted including the underlying molecular and biochemical mechanisms of endocrine disruption in DBM caused by insecticides and their short- and long term effects on DBM.