Effects of sublethal concentration of diazinon, fenitrothion and chlorpyrifos on demographic and some biochemical parameters of predatory bug, Andrallus spinidens Fabricius (Hemiptera: Pentatomidae) in laboratory conditions
2015
Gholamzadeh-Chitgar, Moloud | Hajizadeh, Jalil | Ghadamyari, Mohammad | Karimi-Malati, Azadeh | Hoda, Hassan
Effects of three insecticides, diazinon, fenitrothion and chlorpyrifos on Andrallus spinidens Fabricius (Hemiptera: Pentatomidae), a predator of lepidopterous larvae in rice fields were investigated. The insecticides were applied topically at lethal dose (LD ₃₀) on the fifth instar nymphs of A . spinidens and evaluated on life table and some biochemical parameters of the predatory bugs. The results showed that pre-oviposition period, fecundity and longevity of treated bugs were significantly affected compared with the control. Analysis of life table parameters of A. spinidens revealed adverse effects of insecticides on net reproductive rate (R ₀), intrinsic rate of increase (r), finite rate of increase (λ), doubling time (DT) and mean generation time (T). Among the tested insecticides, fenitrothion was the most toxic insecticide. The lowest value of r was 0.060 day ⁻¹ in fenitrothion. Effects of insecticides on the detoxification enzymes showed that all compounds had inhibitory effect on esterases, acetylcholinesterases and glutathione S-transferases. According to this study, the insecticides cause harmful effects on demographic and biochemical parameters of A. spinidens and are not compatible with the predatory bug even at sublethal concentration.
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