The metabolic mechanisms for metaflumizone resistance in this insect
were analysed. The inhibitor of esterases greatly potentiates the toxicity of this chemical against the field
resistant populations. The synergism ratio is 5.7 and 3.4-fold for S. exigua collected from Huizhou, Guangdong
Province in 2011 and 2012, respectively. The activity of esterases in field populations (HZ12) is also
significantly greater than that in the susceptible strain, and further significantly increased by challenge
with metaflumizone for 3 generations.