sub-lethal effects of insect growth regulators on demographical traits and enzyme activity of spodoptera frugiperda (j. e. smith)

The fall armyworm (faw), scientifically known as spodoptera frugiperda j.e. smith is a polyphagous pest of numerous cultivated crops especially maize causing considerable economic losses in crop production worldwide. thereby, controlling their population is needed. in a present study, the comparative growth, reproduction, and detoxification enzyme activity were evaluated along with exposure to two insect growth regulators (igr) at low lethal doses as compared to the control. results indicate that the larval and pupal developmental time was significantly extended on lufenuron and hexaflumuron as compared to that on the control. similarly, the lowest number of eggs of faw females were recorded on lufenuron (411.84 ± 42.38, 328.75 ± 50.81 eggs at lc10 and lc30, respectively) followed by hexaflumuron (449.58 ± 42.38, 367.33 ± 36.4 eggs, respectively) as compared to that on the control (560.27 ± 13.47 eggs). therefore, it significantly decreased the intrinsic rate of increase (r), finite rate of increase (λ), and net reproduction rate (r0) of offspring generation (f1) when compared to the control. whereas, mean generation time (t) was longer for lufenuron (lc30 28.72±0.47, lc10 31.39±0.99 day) and hexaflumuron (lc30 31.02±0.58, lc10 27.99±0.54 day) compared to control (27.35 ±0.54 days). in addition, a considerably higher activity of all detoxification enzymes in larvae was recorded on lufenuron and hexaflumuron as compared to that on control. these findings are valuable to toxicity and low lethal evaluation of lufenuron and hexaflumuron on life table parameters and enzymatic properties in faw, which may contribute to identifying targets for effective control of faw.