The Research Of Detection Of Hidden Insect Witin Wheat Using Different Methods

The loss of stored grain caused by pest is very serious.So it is still important to find an easy and convenient method for insect detecting and this problem was caused concern from all over world.Based on the background of insect detection,reference method,staining and dissection method,soft X-ray method and LF-NMR method(Including LF-NMR and LF-MRI)were used to study wheat infected by hidden insects rice weevil(Sitophilus oryzae).LF-NMR technology was a new method and was introduced to this research firstly.In this thesis,the main aspect was to detect pests by LF-NMR technology.Wheat and hidden insects rice weevil(Sitophilus oryzae)for the different characteristic signals between them were detected:first study was that different stages of S.oryzae were detected independently by LF-NMR spectroscopy;second part and third part were that using LF-NMR spectroscopy detected rice weevil with four growth period wandering amongst the wheat kernels and S.oryZae growth inside wheat kernels until adults emerging from kernels;last part was that LF-MRI was been used to study S.oryzae growth inside wheat kernels,which were 15,20,25 and 30day after detected by LF-NMR spectroscopy.The conclusions as follows:1.Wheat infested by insect pests whether or not also could be identified by reference method,staining and dissection method and soft X-ray method.It proved that wheat with insect infestation could be detected better using the combinative method between staining and dissection.The relationship between egg-plugs and numbers of rice weevil that used to infested wheat kernels was positive correlation.The relationship between egg-plugs and numbers of dissection was also positive correlation.The result of reference method showed that when more adults were put into wheat,more numbers of offspring were hatch,but there was on significant relationship in numbers of adults and numbers of offspring.When infected wheat detected by soft x-ray,the higher accuracy was found as rice weevil growing.2.A significant difference of signal was found between uninfected wheat and S.oryzae(four periods:larvae,prepupa,pupa and adult).The range of transverse relaxation of uninfected wheat was from 0.66ms to 0.76ms and of insect was from 36ms to 58ms.These results were crucial basis to identity insect infestation in next experiment.3.No matter S.oryzae outside or inside wheat kernel,the signal of insect both could be detected.The signal intensity was enhanced with the number of hidden pests and the size of insects increasing.In addition,the LF-MRI images of uninfected wheat and infected wheat had big discrimination,and four growth periods could be easy to identify.4.Using LF-NMR to detect wheat kernels infested by numbers of rice weevil,it proved that the higher insect infestation caused significant change of signal.The relationship between moisture content of infected wheat and T2b,T22,P2b,P22 were positive correlation.This was same to days of rice weevil growth.But the re lationship between numbers of rice weevil did not show relationship with T22,meaning the feature of S.oryzae was steady.