Pathogen Identification And Pestcides Screening Indoor For Diseases Of Schisandra Chinensis(Turcz.) Baill

In this paper it is for the firstly reported that the occurrence of bacterial canker and root rot of Schisandra chinensis in the world.Pathogens of the three diseases were identified and symptoms of three diseases in detail;Biological characters of Alternaria leaf spot and root rot of Schisandra chinensis were studied;Pesticides for three diseases have been screened indoor.Bacterial canker.Pathogen mainly infect leaves of the plants especially young leaves,older leaves lessly infected.Small brown spots appears on leaves especially margin at early stage of the disease.Leaf margin wilt for lose of water and brown necrosis are observed with the develop of the diseases;Canker formed on stem and branches,serously the appearance of the whole field like as fired.4 pathogenic strains(w₁ w₂ w₃ w₄) are obtained from different parts of the disease plant.Four strains were bacilliform,Gram-negative,peritrichous flagella two or more;could infect Schisandra chinensis,36℃growth negative,5%Nacl growth positive,sucrose reduction positive,potato rot negative,malonic salt negative,gelatin liquefaction negative,indole negative;lecithinase negative,erythromycin sensitivity positive, acided from 11 kinds of carbon include lactose et al,couldn't produce acid from melezitose,α-CH3-D-gluconate,etc.According to concerned parts of《Bergey's Manual of Determinative Bacteriology》9th ed,it may be that the disease was caused by Erwinia sp..Alternaria leaf spot.Disease starts at leaf tip and margin,needlepoint brownish black round lesion on leaves at first,then enlarge as blackish brown round to ellipse spot with ring.Seriously,most of spots combined each other as a big irregular lesion and crack at dry condition,black mould were observed on the back of spots when wet condition.Light greenless-spot appear on fruit off surface,then develop as brown spot, cover most of fruit and lead to seed exposed and fruit dropping off at last;brown oval spot on stem firstly and then spread in length and width and wilt in earlier period of the plant.Conidia were clavate or ovate,brown,constriction,10.4～30.0×7.8～18.0μm with 3-5 transverse and 0-2 longitudinal septa and beaks 5.0～12.0×2.0～3.5μm or no. In view of the morphology and comparison with other concerned species of Alternaria,the pathogens are identified as Alternaria liriodendri T.Y.Zhang et J.Z.Zhang.S.chinensis root rot.It firstly infect the root tips and related root hair areas via wound and cut.The infected root tips and root hairs or other related parts appear as necrosis with the time going on.Necrosis area spreads up and down resulting in parts or the whole of root necrosis,even including the eustipes.The wilted leaves can recover at beging and did not in later and drop off from plants.Microconidium with 1-2cell,ovoid or kidney shape,body 7.0～24×2.0～4.5μm.The figure of macroconidium were fusiform or sickleshaped,bent or straight,pediculated cells, 20～44×2.5～5.0μm with 3 transverse,35～60×3.5～5.0μm with 5 transverse.In view of the morphology and comparison with other concerned species of Fusarium,the pathogens are identified as Fusarium oxysporum Schlecht..Bacterial canker and root rot of Schisandra chinensis are not reported in the world,so Schisandra chinensis are the new record hosts of their pathogens.Species of the pathogen of Alternaria spot are firstly identified.Twelve bactericides to bacterial canker were tested with the lowest effective concentration and the diameter of inhabition zone indoor.Fungicides were screended for two fungical diseases with methods of inhabition zone indoor.The results show that streptomycin sulfate was not only the best effective to inhabit the pathogen,but also the lowest effective concentration to inhabit pathogen,so streptomycin sulfate was the preferred bactericide to Erwinia sp.for field trial.Carbendazol,Topsin-M, Tetramethylthiuram disulfide and Score are effective to pathogens,it is suggested that these fungicides be the first choose in field trail.