Study On Acoustic Detection Technique For Semanotus Bifasciatus (Motschulsky) Larvae

Semanotus bifasciatus(Motschulsky) is a main forest borer in China.In recent years,its damage has constituted a threat to the protection of Platyclatus orientalis in some regions.In 1996,it was recommended to be Forest Plant Quarantine Objects,and cancelled in 2004 quarantine pests list.Today,there are few mature monitoring technology on Semanotus bifasciatus(Motschulsky),using the acoustic signal of larva movement have many advantages,such as simple process,low cost,no environmental pollution,no damage to the tree.Our research attempt to use pest detector and high sensitivity recorder to collect the acoustic signal,and get the analysis results.①The result showed that the suitable temperature for acoustic detection is 20～28℃,and the best is 20℃.Because in this temperature range the larva's activity of Semanotus bifasciatus are more frequently,and reached the peak value on 20℃,it provides reference for field monitoring.The distribution of larva in wood and the choosing of measure point cause significant effect on the results.②The movement of larvae contains feeding and creeping,63.7%proportion of the movement is feeding,and creeping get 36.3%,The acoustic signal energy of feeding is much more than creeping.③In the lab,using self-made Deafening chest to cut the noise,Research on Verification shows the effect meet the requirement,in field,using artificial neural net and wave filter to eliminate noise, extract pure acoustic signal.④By the research of acoustic signal and source position,the effective detection scope of AED2000 can reach to 1.70 metres.⑤The number of Semanotus bifasciatus(Motschulsky) acoustic signal increased by the raise of insect density,shows the linear relationship,the indoor function formula in march,april,may are:y =1.178x-0.306,y=1.989x-0.718 and y=3.554x+0.169.and in field the function formula in march, april,may are:y=1.668x+1.040,y=2.229x+0.707 and y=3.648x+0.887.