植物土传病原菌立枯丝核菌课件

植物土传病原真菌 立枯丝核菌（Rhizoctonia solani ） 一、Rhizoctonia solani 的介绍 土传的三大病原真菌 镰刀菌(Fusarium spp) 腐霉菌 (Pythium spp.) 立枯丝核菌（Rhizoctonia solani ） 是一个非常重要的土传植物病原真菌 半知菌亚门丝孢纲无孢目丝核菌属 1、命名与融合群 丝核菌 l单核丝核菌 l双核丝核菌 l多核丝核菌 多核 双核 单核 Binucleate hyphae 时间时间 Date学名 scientific name作者 Author(s) 1910 Sclerotium irregulare Shirai Miyake 1912 Hypochnus sasakii Shirai Sawada 1928 Corticium vagum Berk 幼期营养菌丝中远基的细胞隔膜附近分枝、老熟分 枝与再分枝一般呈直角； 分枝发生点附近缢缩并形成一隔膜； 有明显的桶孔隔膜 呈各种深浅不同的褐色。 Microscopic view of Rhizoctonia solani mycelium constricted O：Occlusion O1：Granular O2：striated band P1：regularly perforate P2：imperforate P3-P5：Vesiculate P6：parenthesome absent Multinucleate hyphae 、通常存在的特征： l产生念珠状细胞； l产生菌核，且菌核有内外层分化，但不分化成菌环和 菌髓； l菌丝直径大于5m，大多数为5-14m，平均6-10m； l生长迅速； l致病性；可引起枯萎、猝倒、种腐、果腐和烂根。致 病力可从无致病力到强致病力。寄主范围变化也很大 ，可由有限到相当广。 Moniliod cells Moniliod cells of Rhizoctonia solani. These specialized hyphae are produced in dense aggregates to form survival structures called bulbils 绝对没有的特征（彭绍裘等，1986） ： l锁状联合(锁状联合是双核菌丝的鉴定标准， 凡是产生锁状联合的菌丝均可断定为双核 )； l分生孢子； l分化为菌环与菌髓的菌核； l菌索； l除褐色以外的其它色素； l除T.cucumeris以外的其它有性态 有性型特征 3、危害性（寄主范围） 侵染水稻 、小麦、玉米、棉花、大豆、马铃薯、粟 、洋麻等农作物 引起林木花卉如各种苗木、香石竹、菊花、鸡冠花 、鸢尾等发生立枯、猝倒、茎腐、基腐和根腐等多 种类型的病害。 寄主范围十分广泛，在世界范围内侵染43科260多 种植物，引起寄主发生严重的病害（生越明，1984 ）。 在自然环境，. solani以腐生、寄生或共生三种方 式生存，对环境的适应能力强，形成的菌核在土壤 中可以存活2年多（Kozaka 1975），是一种防治困 难的病原菌。 危害特点 1、寄主范围广 2、存活能力强 3、遗传多样性丰富 4、IGS引起寄主的病害 AG 1-IA lsheath blight, sheath spot rice l sclerotial disease, leaf blight, banded leaf corn l leaf blight, banded leafsorghum（高粱） l leaf blightbean l leaf blightsoybean l summer blight crimson clover（深红三叶草） l southern blight camphor（樟脑） seedlings l brown patch turfgrass（草皮草） AG 1-IB lweb blight bean rice soybean figs leguminosous Hortensia（绣球花） lrot cabbage lbottom rot（底腐病） lettuce AG 1-IC ldamping off buckwheat（荞麦） l damping off and crown root rotcarrot l damping off soybean flax pine AG 2-2 IIIB lfalse sheath blightrice lsheath blight mat rush ginger gladiolos lblack scurf edible burdock（牛蒡） lbrown patchturf grass lcrown and brace rotcorn ldamping off sugar beet tree seedlings crhysanthemum root rotkonjak（魔芋） AG 4 (HG I, HGII and HGIII) lfruit rottomato lstem rotpea l damping off and stem canker potato ldamping off and root rots soybean lobolly pine seedlings onion Stevia（甜叶菊） pea snap bean cotton peanuts slash lpod rot snap bean AG 5 lblack scurf potato lbrown patchturf grass lroot rot beans soybeans adzuki beans AG 6nonpathogenic group - AG 7nonpathogenic - AG 8bare patchescereals AG 9weak pathogencrucifers potatoes AG 10 nonpathogenic - AG 11 wheat AG BI nonpathogenic - 引起不常见植物病害 Begonia Diseases：Rhizoctonia Crown Rot Easter Lily Diseases ：Rhizoctonia Stem Rot Fern Diseases: Rhizoctonia Blight Fuchsia Diseases ：Rhizoctonia Root Rot Gerbera Diseases ：Rhizoctonia Crown Rot Poinsettia Diseases： Rhizoctonia Root Rot Gypsophila Diseases ：Rhizoctonia Stem Rot Impatiens： Damping-Off ，Rhizoctonia Stem Rot Primula Rhizoctonia Crown Rot and Bud Blight Pothos Rhizoctonia Stem Rot Statice Rhizoctonia Crown Rot Snapdragon Rhizoctonia Stem Rot A chile plant infected by R. solani, with a reddish-brown discoloration at the soil line level of the stem 危害症状 Garden mum（菊花） - Rhizoctonia foliar blight /pub/search/topsearch.asp?page=http:/w /greenhouse/pestsdis/gallery/index.html closeup 危害症状 Target spot lesion on tobacco caused by Rhizoctonia solani Belly rot of cucumber caused by Rhizoctonia solani Head rot, caused by Rhizoctonia solani, on cabbage. 危害症状 Headrot of cabbage Bottom Rot of Cabbage 危害症状 危害症状 Wire stem of cabbage Wire stem symptoms on lower stem of broccoli（椰菜） plant. 危害症状 Rhizoctonia Damping-Off and Stem Rot of Soybeans in the field. 危害症状 Rhizoctonia Damping-Off and Stem Rot of Soybeans Characteristic reddish-brown sunken cankers on the hypocotyl caused by Rhizoctonia solani. 危害症状 Bean Rhizoctonia root rot (R. solani ) 危害症状 BEET: Damping-Off (Rhizoctonia solani plus other genera ) 危害症状 Sugarbeet Rhizoctonia Root and Crown Rot Pathogen: Rhizoctonia solani Root symptoms of Rhizoctonia 危害症状 LETTUCE: Bottom Rot (Rhizoctonia solani ) 危害症状 TOMATO: Soil Rot (Rhizoctonia solani ) Rhizoctonia damping-off and fruit rot 危害症状 Rhizoctoni a Diseases of Turfgrass Turfgrass Rhizoctonia Blight Pathogens: Rhizoctonia solani and R. cerealis 危害症状 Sparse growth of turf due to seedling damping off caused by Pythium spp., Rhizoctonia spp., Fusarium spp., and/or Helminthosporium spp. 危害症状 Sore shin on cotton seedlings the primary agents are Rhizoctonia solani, Pythium spp., Phoma exigua (Ascochyta), and Fusarium spp. 危害症状 Rhizoctonia Disease of Potato 危害症状 Scab of Potato Tubers caused by the fungus Rhizoctonia 危害症状 Rhizoctonia Stem and Stolon Canker of Potato 危害症状 Rhizoctonia Root, Stem, and Crown Rot of Alfalfa(紫花苜蓿) Rhizoctonia lesions on alfalfa taproots Rhizoctonia lesions on alfalfa stems Crown rot caused by Rhizoctonia 危害症状 Rhizoctonia blight sharp eyespot of dwarf winter wheat Rhizoctonia cereal 危害症状 危害症状识别 1.立枯 2.猝倒 3.水渍斑块 4.疮痂 5、life cycle Parmeter, 1970 and Agrios, 1988 Spatial distribution and spread of R. solani Soil-borne pathogens have limited means of spread in the field and it is usually the host plant that inadvertently grows towards the stationary pathogen (Gilligan, 1983). R. solani may grow from one plant to another and spread the disease as well as the inoculum. the disease produced by R. solani depends upon balance between the primary and the secondary inoculum which are interdependent (Bailey and Gilligan, 1999). What factors affect the spatial distribution as well as growth and spread of R. solani in the field. Three main factors responsible for patterns of the spatial distribution and spread of the fungus: the host plant, the intrinsic characteristics of the pathogen and the environment. Host plant lThe presence of a susceptible host plant is necessary for the disease to deve lop while the extent to which the disease spreadsdepends on the degree of susceptibility of the plant population. Intrinsic characteristics of the pathogen lIt is quite important to know how R. solani survives in unfavourable environmental conditions. Unfavourable ecological conditions may comprise the absence of a susceptible host, lack of nutrients, competition with microflora, etc lBesides survival, the second important question regarding the pathogen is the rate of growth to produce secondary infection lAnother important factor is the competitiveness and virulence of the pathogen in the given environment (Papavizas, 1970). Environment lThe biotic and abiotic components of the soil environment constitute a complex set of interacting factors which influence the growth and spread of R. solani. lSoil-borne pathogens live in soil, their activities are highly affected by soil properties and the cultural practices that disturb the soil. Soil physical conditions play an important role in the extent, rate and variability ofmycelial growth of R. solani (Otten and Gilligan, 1998; Otten et al., 1999). lThe extent and rate of fungal growth may depend on the soil porosity（空隙） because there is restricted space available which limits the spread of the hyphae of R. solani. lAnother important factor is soil moisture as growth and spread of R. solani is favoured by drought (Smiley et al., 1996). lThe distribution, size and quality of substrate present in the soil may affect the activity of soil-borne fungal mycelia (Griffith and Bardgett, 2000) Cultural practices alter the soil structure and its physicochemical properties, and thus have a considerable influence on the fungal growth and spread. lMinimum tillage（免耕法） lcrop rotation It seems that the multiple ecological requirements of R. solani are able to compensate（补偿） themselves when a few of them are not fulfilled by the environment, which may explain the large distribution of this fungus and the frequent occurrence of Rhizoctonia patches. These observations suggest that we must consider how appropriate agricultural practices promote conditions which may affect the soil inoculum potential towards Rhizoctonia disease. 6. Disease control A variety of measures have been reported in the literature to control the disease. As far as chemical control is concerned, contrasting reports can be found. None of the available seed treatment fungicides move systemically to roots (Paulitz et al., 2002). In conclusion, there is no single method of chemical control of epidemics caused by R. solani that is effective, economically practical and environmentally safe. 化学防治 lAzoxystrobin(亚托敏) lChlorothalonil(百菌清) letridiazole (Thiadiazole: ethyl 3-trichloromethyl-1,2,4- thiadiazol-5-ylether) letridiazole (依得利)+ thiophanatemethyl lFludioxonil(4-(2,2-difluoro-1,3-benzodioxol-4-yl)pyrrole- 3-carbonitrile) lIprodione( 依普同) lTerraclor (Quintozene：五氯硝基苯) lmancozeb lTriflumizole(赛福座) l井冈霉素 耕作方式方式 Crop rotation has also been reported to decrease the disease in various AGs as described earlier, however, it cannot be used alone to control the disease because the pathogen has a wide host spectrum and can escape even the long rotations (Balali et al., 1995). 生物防治 Biological control