Controlling Effect Of Different Extreme Temperatures On The Adults Of Sitophilus Zeamais Motschulsky

The adults of Sitophilus zeamais Motschulsky were researched in this study The different temperatures(high temperatures/43,47,51,55?,low temperatures/-8,-12,-16,-20?)were setted in order to research the change of mortality,moisture content and the activity of protective enzymes(SOD,POD,CAT)of S.zeamais.The adults of S.zeamais,both in normal environment and exercise high and low temperature calibration,were studied after extreme high and low temperature treatment for different times,provide a theoretical basis for scientific and efficient implementation of insecticidal extreme temperature treatment.The specific results are as follows:With the extension of processing time,the mortality of test insects in normal environment was increased significantly,body moisture content of insect was decreased gradually,the activity of protective enzyme rising at first and then downward on the whole after treatment,Extreme high temperature above 50? has obvious effect on lethal of S.zeamais.But the change of body moisture of insect in not obvious and the activity of POD and CAT is lower than insect after 43?,47?treatments.The results show that moisture loss and reduce of activity of protective enzyme is the important factors for insect death when experience extreme high temperature short time.The mortality rate of test insect,which experiences high temperature,is lower than normal insect after the same high temperature treatment.When the exercise time is longer,the corrected mortality is lower.The body moisture content of insects after 3 hours high temperature treatment is significantly higher than the control.But the mortality is lower than the control group,indicating that water content is probably one of the factors influencing heat resistance of insects.The activity of protective enzyme of insect exercising 5 hours high temperature treatment is stronger than the control,and mortality was significantly lower than the control group,indicating that protective enzyme activity may also affect heat resistance of insects.After treatment with extreme low temperature,the mortality of test insect increased but the body moisture of insect has no obvious change with the extension of processing time,which show moisture of insect may not be the main factors influencing the pests died when treated with extreme low temperature.,The activity of protective enzyme of insect decreases after rising first with the extension of treatment time,the decline of enzyme activity may be an important reason that resulted in the deaths of pests.After the same low temperature treatment,the mortality of experienced cold hardening test insect is significantly lower than the control after-8,-20? low temperature treatments,but the body moisture content of insect has no difference while the activity of protective enzyme is stronger than the control.The mortality of insect experience cold hardening 8 hours test is lower than control when treat with-12? low temperature.The biggest mortality rate,moisture content,activity of protective enzyme of insect experience cold hardening has no difference with the control when treatment with-16? low temperature.This result showed that the insect resistance to milder low temperature or extreme low temperature for short time is improved after experienced cold hardening.