The Insecticide Resistance Of Chlorpyrifos On Plutella Xylostella L. Due To Rearing Temperatures

Diamondback moth (Plutella xylostella L.), which belongs to Lepidoptera Plutellidae, is one of the most important worldwide pests, with high insecticide resistance, to cruciferous vegetables.is To provide theoretical basis for Plutella xylostella integrated management, studies to Plutella xylostella raised on different temperature on the resistance to chlorpyrifos , the change of AchE and CarE, were conducted. The results are summarized as follows:(1) Due to the rearing temperatures between 10 and 30, resistance and enzyme activity increase with the rising of rearing temperature. And, the regression equations are given below:a)for the relationship of LDso of susceptible strain and rearing temperature: y= -0.1144 x2+0.0803x-0.3649, R2=0.9760;b)for the relationship of LD50 of resistant strain and rearing temperature: y=-0.0058x2+0.7025x+3.0554, R2=0.9634;c)for the relationship of AchE activity of susceptible strain and raised temperature: y=4E-06x2-7E-05x+0.0052, R2=0.9940;d)foe the relationship of AchE activity of resistant strain and rearing temperature: y=-3E-06x2+0.0002x+0.0046, R2=0.9855;e)for the relationship of CarE activity of susceptible strain and rearing temperature: y=0.006x2-0.0082x+0.438, R2=0.9836;f)for the relationship of CarE activity of resistant strain and rearingtemperature: y=0.0031x2-0.0592x+0.8812, R2=0.9935;g)for the relationship of AchE activity of susceptible strain and resistance: y=0.0897x2-0.2487x+1.1598, R2=0.9815;h)for the relationship of AchE activity of resistant strain and resistance: y=-0.1996 x2+0.955x+0.2675, R2=0.9676;i)for the relationship of CarE activity of susceptible strain and resistance: y=0.1322x2-0.3196x+l.1925, R2=0.9820;j)for the relationship of CarE activity of resistant strain and resistance: y=3.1380x2-7.0931x+5.1018, R2=0.9654c(2) The sensitivity of chlorpyrifos on the larvae of diamondback moth raised on 5癈 is lower than that of raised on 20 C. Accordingly, the activities of AchE and CarE on the larvae of diamondback moth raised on 5 C are much more than that of raised within the range of 10C to 30 "C.The enzyme activity is inhibited of the diamondback moth raise on 35 C and with the reduction of LD50 to chlorpyrifos.(3) The recovery rate of the CarE activity is different after the inhibition of chlorpyrifos to CarE from the larvae of diamondback moth raised on different temperature.