Study On Biological Characteristics And Control Technology Of Xinjiang Agrilus Planipennis

Agrilus planipennis Fairmaire（emerald ash borer,EAB）is a forestry pest which endangers the Fairmaire,Oleaceae plants.Since 1966,the pest damaged seriously Fairmaire rhynchophylla Hance,F.americana Linn and F.velutina Toor in Northeast China.EAB have caused death of numerous introduced ashes and damaged the death of F.bungeana Toor in its National Nature Reserve in Yili,Xinjiang since EAB invaded into Xinjiang.In order to prevent the further spread and outbreak of EAB in Xinjiang,this study clarified the life history and spatial distribution of EAB in Manas County,Xinjiang,and then determined the key control time of EAB.Then,the toxicity of adults was determined indoors to determine the best chemical control agent and recommended concentration of adults,and the best agent,concentration and injection time of trunk injection in larval stage were determined outdoors.And the best release age of two Sclerodermus species was determined and their field control effects were determined.Finally,a comprehensive prevention and control technology system based on chemical control and biological control was formed.The results were as follows:1.Biological characteristics of EAB:EAB has one generation per year and overwintered as mature larvae in xylem in Manas County of Xinjiang,from early May to mid-May is the pupation stage,from early May to late June is the adult emergence stage,from mid-May to early July is the adult oviposition and larval hatching stage,from early June to late October is the larval damage stage,from late July the larvae began to bore into the xylem damage,from late July to early April next year is the larval overwintering stage.Therefore,the best control period of EAB is the early stage of adult emergence（late April to early May）,the peak of adult emergence（early May to early June）and the larval phloem damage period（early June to mid-July）.2.The EAB distribution on F.velutina:the EAB adults major laid eggs on the 1～2 m trunks and the emergence holes the 2～3 m,and most larva were distributed below 4 m which is similar with the adult emergence holes.The number of EAB eggs laid on host plant was influenced by the bark thickness and it was decreased significantly when the bark thickness more than 6 mm,and there was no significant correlation distribution of EAB and the DBH of host plants.3.Toxicity determination of different insecticides on adults of EAB:Indoor toxicity test showed that the LT₅₀of 500-fold diluted solution of 8%beta-cypermethrin SC was the smallest（201.00 min）,followed by 500-fold diluted solution of 5%emamectin benzoate ME（205.20 h）.The toxicity of 8%beta-cypermethrin SC was the highest at 6 h,and the LC₅₀value was the smallest(1 144.00 mg·L^-1).the toxicity of 5%emamectin benzoate ME was the highest at 12 h and 24 h,and the LC₅₀values(852.11 mg·L^-1,178.83 mg·L^-1)were the smallest.3.The mortality of 5%emamectin benzoate ME reached 100%at 24 h,and the corrected mortality（80.19±3.43%）of 8%beta-cypermethrin SC diluted 500 times was the highest at 12 h.4.Control effect of different insecticides on EAB Larvae:the control effect of 20%dinotefuran SC stock solution on 1～2 instar larvae of EAB was the best after injection（83.60±3.55%）,and the effect of 70%imidacloprid WG diluted 10 times（96.87±1.77%）was the best after dilution of different agents,followed by 2%thiamethoxam SC diluted 1 times（87.73±9.54%）.The larvae injected on June 21st（1～2 instar larvae）had the highest mortality and the best effect.5.Parasitic effects of two species of Sclerodermus on EAB:the results of indoor artificial inoculation showed that the parasitoid-host ratios of the two species of Sclerodermus wasps to the4th instar larvae of EAB was significantly higher than other instars.When parasitoid-host ratios was 4:1,the parasitism rate of the two species of Sclerodermus wasps to the larvae of EAB was significantly higher than that other wasps.Under natural conditions,the average longevity of the two bee adults is about 35 days.The parasitism rate of Sclerodermus pupariae Yang et Yao was higher than that of S.guani Xiao et Wu by releasing different natural enemies and different ratio of parasitoid-host in the 3～4 instar larvae.The ratio of parasitoid-host ratios（15:1）had the highest parasitism rate（37.59±5.50%）and the best parasitism effect.