《植物病虫害绿色防控技术》课件-三、玉米纹枯病绿色防控（双语版）

玉米纹枯病绿色防控

GreenPreventionandControlofCornSheathBlight

玉米纹枯病又称玉米烂脚瘟，我国始见于1966年的吉林省，在上世纪70年代中后期逐渐成为我国玉米主产区的一种重要病害。在四川、重庆、贵州、江苏、浙江、河南、陕西、山东等省及两湖、两广地区的春、夏、秋玉米均有纹枯病的发生。一般年份发病率达40%，严重时发病率达70%。

Cornsheathblight,alsoknownascornrotblight,wasfirstseeninJilinProvincein1966andgraduallybecameoneofthemajordiseasesinthemaincorn-productionareasinChinainthemiddleandlate1970s.SheathblightoccursinSichuan,Chongqing,Guizhou,Jiangsu,Zhejiang,Henan,Shaanxi,Shandongandotherprovinces,aswellasinspring,summerandautumninHunan,Hubei,GuangdongandGuangxi.Theincidenceincommonyearsis40%,or70%inseriouscases.三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight（一）症状识别

SymptomIdentification

玉米纹枯病从苗期至穗期均可发生，危害高峰期在玉米子粒形成至灌浆充实期。该病主要危害叶鞘、叶片和穗部，也侵害茎秆。最初多由近地面的叶鞘发病，由下而上逐步发展。

Cornsheathblightcanoccurfromtheseedlingstagetotheheadingstage,andthepeakharmperiodisfromtheformationofcornkernelstothefillingstage.Thediseasemainlyharmsleafsheaths,leavesandears,andalsoharmsstems.Atfirst,thediseasemostlyoccursfromtheleafsheathneartheground,

andgraduallydevelopsfrombottomtotop.其症状为在叶片和叶鞘上形成典型的呈暗绿色水浸状的同心斑，大面积覆盖被侵染叶片和苞叶，形成不规则的云纹状病斑，中部灰褐色，边缘深褐色，随后病斑逐渐扩大，包围整个叶鞘直至叶鞘叶片干枯；病斑向上扩展至果穗基部，果穗停止发育并迅速发展至全穗，最后死亡。

Thesymptomsincludethattypicaldarkgreenwater-soakedconcentricspotsareformedontheleavesandleafsheaths,coveringtheinfectedleavesandbractsinalargeareatoformirregularmoire-likespots,withgrayishbrowninthemiddleanddarkbrownontheedges,andthenthespotsgraduallyexpandandsurroundthewholeleafsheathuntiltheleavesoftheleafsheathswither.Spotsspreadupwardtothebaseoftheears,whichstopdevelopingandrapidlydeveloptothewholeears,andfinally,theearsdie.三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight三玉米纹枯病绿色防控

III.GreenPreventionandControlofCornSheathBlight环境潮湿时，病斑上可看见稀疏的白色蛛丝状菌丝体。病组织内或叶鞘与茎秆之间常产生褐色颗粒状菌核，菌核周围有少量菌丝和寄主相连。成熟的菌核灰褐色，大小不等，形状各异，多为扁圆形，极易脱离寄主，遗落田间。Whentheenvironmentiswet,sparsewhitearachnoidmyceliumcanbeseenonthespots.Browngranularsclerotiaareoftenproducedindiseasedtissuesorbetweenleafsheathsandstems,andasmallamountofhyphaeareconnectedtothehostaroundthesclerotia.Maturesclerotiaaregrayishbrown,indifferentsizesandshapes,mostlyoblate.Theymayeasilydetachfromthehostandbeleftinthefield.三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight（二）病原

多数研究者认为，玉米纹枯病的病原菌主要由半知菌亚门的立枯丝核菌、禾谷丝核菌和玉蜀黍丝核菌3个种，其中玉蜀黍丝核菌常危害果穗导致穗腐，禾谷丝核菌主要侵害小麦，而玉米纹枯病的主要病原菌是立枯丝核菌。

Mostresearchersbelievethatthepathogensofcornsheathblightmainlyconsistofthreespecies:Rhizoctoniasolaniofdeuteromycotina,RhizochondriacerealisandRhizoctoniazeaeVoorhees.RhizoctoniazeaeVoorheesoftenharmsfruitearsandcausesearrot.Rhizochondriacerealismainlyharmswheat,whilethemainpathogenofcornsheathblightisRhizoctoniasolani.玉米纹枯病菌丝幼嫩时无色，较细，分枝呈直角、近直角或锐角，分枝处大多有缢缩现象，离分枝不远处有隔膜。菌丝细胞多核，一般3～10个，多数4～6个。随菌龄和分枝增加，新分枝细胞渐变粗短，达一定程度后纠结成菌核。菌核初为白色，后变为不同程度褐色，上凸底凹或平，球形或椭圆形，表面粗糙，单生或多个结成不规则形，表面有许多微孔。

Thehyphaeofcornsheathblightarecolorlessandthinwhenyoung,withbranchesatright,nearlyright,oracuteangles.Mostofthebranchesareconstricted,andthereisaseptumnotfarfromthebranches.Hyphaearemultinucleated,generally3~10,mostly4~6.Withtheincreaseoffungusinstarandbranches,thenewlybranchedcellsgraduallybecomethickerandshorter,andthenbecomesclerotiaafterreachingacertaindegree.Thesclerotiaarewhiteatfirst,thenbrownofvaryingdegrees,concaveorflatontheupperpart,sphericaloroval,roughonthesurface,solitaryorirregularinshape,withmanymicroporesonthesurface.三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight（三）发生规律

OccurrenceRegularity

初侵染源为玉米田土表和浅土层中的越冬菌核。在温湿度、光照条件适宜时，越冬菌核开始萌发菌丝，侵染玉米植株基部叶鞘，通过病、健叶片和叶鞘相互搭接等可造成再侵染，使病害逐步向上蔓延扩展引发玉米纹枯病。Theprimaryinfectionsourceisoverwinteringsclerotiaonthesurfaceofcornfieldsandintheshallowsoillayer.Whenthetemperature,humidity,andlightconditionsaresuitable,theoverwinteringsclerotiabegintogerminatehyphaeandinfecttheleafsheathsatthebaseofcornplants.Reinfectioncanbecausedbyoverlappingthediseasedandhealthyleaves,andleafsheaths,sothatthediseasegraduallyspreadsupwardandexpands,causingcornsheathblight.病菌可通过表皮、气孔和自然孔口3种途径侵入寄主，其中以表皮直接侵入为主。多雨潮湿时病部长出稠密的白色菌丝体，之后菌丝密集成多个菌核，最初为白色，后变为褐色，最后呈暗褐色。成熟的菌核多为圆形或扁圆形，易脱离寄主，遗落田间成为再次侵染的菌源。玉米种子和病株残体可带菌，但不能引起玉米植株发病。

Pathogenicbacteriacaninvadethehostinthreeways:epidermis,stomataandnaturalstomata,ofwhichthedirectinvasionofepidermisisthemainway.Whenitisrainyandwet,densewhitemyceliumwillgrowattheaffectedpart,andthenthehyphaearedenselyintegratedwithmultiplesclerotia,initiallywhite,thenbrown,andfinallydarkbrown.Thematuresclerotiaaremostlyroundoroblate,whichareeasytodetachfromthehostandbecomethesourceofsecondaryinfectioninthefield.Cornseedsanddiseasedplantresiduesmaycarrybacteria,buttheycannotcausecornplantdiseases.

三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight玉米纹枯病病菌属高温高速型菌群，病菌发育适温为28～32℃，在30℃和有足够的湿度时2d就形成新的菌核。连续阴雨或天气湿闷有利发病。过分密植，施氮过多，植地连作或前作地为水稻纹枯病严重的田块本病往往发生严重。三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight三玉米纹枯病绿色防控

III.GreenPreventionandControlofCornSheathBlightCornsheathblightpathogenicbacteriaisahigh-temperatureandhigh-speedflora.Theoptimumtemperatureforpathogendevelopmentis28–32°C,andnewsclerotiawillbeformedin2daysat30°Cwithsufficienthumidity.Continuousrainorwetandstuffyweatherisconducivetotheonsetofthedisease.Excessivelydenseplantingandexcessivenitrogenapplicationoftenleadtoseriousdiseaseinfieldswithcontinuouscroppingorpre-croppingricesheathblight.（四）防治技术

ControlTechnique

1、控制菌源玉米收获后，及时深耕灭茬，清除病原及时深翻消除病残体及菌核，集中烧毁或高温堆肥，尽量减少侵染来源；发病初期摘除病叶，并用药剂涂抹叶鞘等发病部位。1.Controlbacterialsource:Afterthecornisharvested,deepplowingandstubbleremovalshouldbecarriedoutintime,pathogensshouldberemoved,diseasedresiduesandsclerotiashouldbeeliminatedintime,andcentralizedburningorhigh-temperaturecompostingshouldbeadoptedtominimizeinfectionsource;attheearlystageofthedisease,thediseasedleavesshouldberemovedandthediseasedpartssuchasleafsheathsshouldbeappliedwithchemicals.

2、选用抗、耐病品种目前生产上尚无对玉米纹枯病免疫的品种，高抗纹枯病的品种也较少，但是选用早熟、耐病、高产的玉米良种，同样条件可降低病情20%～30%。2.Selectdisease-resistantcultivars.Atpresent,therearenocultivarsimmunetocornsheathblightinproduction,andtherearefewcultivarswithhighresistancetosheathblight.However,selectingearly-maturing,disease-resistantandhigh-yieldingcorncultivarscanreducethediseaseby20%~30%underthesameconditions.三玉米纹枯病绿色防控III.GreenPreventionandControlofCornSheathBlight

3、加强栽培管理实行轮作，合理密植，及时排除田间积水，降低田间湿度，消灭田间杂草。合理施肥，避免氮肥施用过多，以控制病害发生。

3.Strengthencultivationmanagement:Croprotationshouldbecarriedout,plantingshoul