| Pinus tobulaeformis die-back is endemic species in China,it is also a fine tree species for buildingand park virescence. In recent years a large number of Pinus tabulaeformis in shenyang area in liaoningprovince oil pine is death，at present this disease research has not reported in the world．In order to clear upthe causes of disease，regularity, prevention，control measures and so on，this article carry out a lot of theinvestigation and research，the main research of the disease contains the occurring law and pathogens ofidentification and inoculation test，experiment of biology pathogens, indoor prevention drug screening，drug screening tests in field．in the future This paper make a good theory basis for prevention and control ofthis disease．Specific research results are as follows：The occurrence of Pinus tobulaeformis die-back in Shenyang was investigated by random samplingand on-the-spot field observation，and the occurrence regularity was also analyzed. The results showedthat：the disease was common in Shenyang．The average disease rate and index were47.23%and14.88respectively. The occurrence of the disease was correlated with forest site and stand factor. adretto is light，which the average disease rate and index were79.38%and31.41respectively; Pinus tabulaeformis of20to30years old took a serious disease, which the average disease rate and index were80.02%and40.94respectively；the higher of stand density, the disease is more serious．The sample area of which standdensity is bigger than50plants per acres, which the average disease rate and index were93.04%and47.22respectively; Pinus tabulaeformis of over15meter high take a serious disease，which the average diseaserate and index were97.28%and46.21respectively；the mingled forest with Pinus tabulaeformis andKorean pine was serious，which the average incidence and index were100%and68.59respectively．By means of field collected specimens，the results of morphological identification and molecularbiology identification show that there are two kinds of the pathogen of Pinus tobulaeformis die-back．Oneis Cenangium ferruginosum, belonged to Ascomycota, Discomycete，Helotiales，Leotiaceae，Cenangium；The other one is Nectria cucurbitula belonged to Ascomycota，Discomycete，Hypocreales，Hypocreaceae，Nectria，and it’s a new record pathogen on domestic Pinus tobulaeformis．The antimicrobial effects of18fungicides on mycelium growth and conidia germinations ofCenangium ferruginosum and Nectria.cucurbitula were researched in laboratory. The results of the studyshow that: among these18agents of fungicides, the antimicrobial effects of6fungicides on myceliumgrowth of Cenangium ferruginosum canreach100%. They were1000-times diluents of tuzet,1000-times diluents of mancozeb,50-timesdiluents ofcarbendazim,50-times diluents of thiram,100-times diluents of fruit net and1000-timesdiluents of niacinamide, respectively. The relative antimicrobial rate of13agents among fungicidescan achieve100%on conidia germinations of Cenangium ferruginosum. They were1000-times diluents ofchlorothalonil, zineb, mildothane, asomate, Tuzet, mancozeb, fierce zinc、black leaves spirit、fruit net、rocephin,500-times diluents of niacinamide、carbendazim and300-times diluents of difenoconazole. Theantimicrobial rate of5fungicides on mycelium growth of Nectria.cucurbitula can reach100%. They were1000-times diluents of tuzet,1000-times diluents of mancozeb,50-times diluents ofcarbendazim,100-times diluents of fruit net and1000-times diluents of niacinamide, respectively. These indicate thattuzet, mancozeb, fruit net and niacinamide have the best antimicrobial effects on the pine blight.Tuzet500、800、1000times liquid，mancozeb500、800、1000times liquid，fruit net500、800、 1000times liquid and benzene mytery500、800、1000times liquid were used Pinus tobulaeformis die-backprevention experiment on5blocks of experiment plot of2hm2on Shenyang Qipan mountain area in Augustand September2010，surveying average incidence and average disease index and calculating controlefficiency．Community prevention experiment results show that：tuzet800times liquid and mancozeb500times liquid have the best control efficiency，and fruit net1000times liquid has the worst controleffiency．Tuzet800times liquid and mancozeb500times liquid were used the forest small area ofprevention experiment．Experiment results show that：both tuzet800times liquid and mancozeb500timesliquid have about80%control efficiency about incidence and about65%control efficiency about diseaseindex．They don’t have significant difference．So both tuzet800times liquid and mancozeb500timesliquid are the effective agent against Pinus tobulaeformis die-back．... |
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