《植物病虫害绿色防控技术》课件-二、油菜霜霉病绿色防控（双语）

二油菜霜霉病绿色防控

II

GreenPreventionandControlofRapeDownyMildew

油菜霜霉病我国各油菜区重要病害，长江流域、东南沿海受害重。一般发病率为10%～30%，严重时达80%以上。

Rapedownymildew:ItisanimportantdiseaseinvariousraperegionsinChina,whichseriouslyharmstheYangtzeRiverBasinandthesoutheastcoast.Thegeneralincidencerateis10%~30%,andreachesabove80%inseverecases.（一）症状识别

油菜各生育期均可感病，为害油菜地上部分各器官。

叶片：发病后，初为淡黄色斑点，后扩大成黄褐色大斑，受叶脉限制呈不规则形，叶背面病斑上出现霜状霉层。二油菜霜霉病绿色防控II

GreenPreventionandControlofRapeDownyMildew

(I)SymptomIdentification

Rapeissusceptibletothediseaseatallgrowthstages,causingharmtothe

abovegroundorgansofrape.

Leaves:Aftertheonsetofthedisease,lightyellowspotsappearatfirst,andthenexpandintolargeyellowish-brownspots,whichareirregularlyshapedduetothelimitationofleafveins.Adownymoldlayerappearsonthespotsonthebackoftheleaves.油菜霜霉病病叶正面症状油菜霜霉病病叶背面症状SymptomsontheFrontofDownyMildewDiseasedLeavesofRapeSymptomsontheBackofDownyMildewDiseasedLeavesofRape

茎、薹、分枝和花梗：感病后，初生褪绿斑点，后扩大成黄褐色不规则形斑块，斑上有霜霉病菌。花梗发病后有时肥肿、畸形，花器变绿、肿大，呈“龙头”状，表面光滑，上有霜状霉层。严重时全株发病，布满霜霉，变褐枯死。

Stems,stalks,branches,andpedicels:Afterinfectedwiththedisease,chloroticspotsappearfirst,andthenexpandintoyellowish-brownirregularpatcheswithdownymildewonthespots.Aftertheonsetofthepedicel,sometimesitisswollenanddeformed,andthefloralorgansturngreenandswollen,showinga"dragonhead"shapewithasmoothsurfaceandafrostymoldlayer.Inseverecases,thewholeplantbecomesdiseased,andiscoveredwithdownymildew,andturnsbrownandwitherstodeath.（二）病原寄生霜霉，属鞭毛菌亚门真菌油菜霜霉病病菌孢囊梗及孢子囊2.孢子囊

3.孢子囊的萌发4.卵孢子

(II)EtiologyParasiticdownymildew,belongingtoflagellariasubphylumfungi

DownymildewpathogenofrapeSporangiophoresandsporangia2.Sporangia3.Germinationofsporangia4.Oospores（三）发病规律越夏：冬油菜区，病菌以卵孢子随病残体在土壤中、粪肥里和种子内越夏，秋季萌发后侵染幼苗，病斑上产生孢子囊进行再侵染。越冬：冬季病害扩展不快，并以菌丝在病叶中越冬，翌春气温升高，又产生孢子囊借风雨传播再次侵染叶、茎及角果，油菜进入成熟期，病部又产生卵孢子，可多次再侵染。远距离传播主要靠混在种子中的卵孢子。至于近距离传播，除混在种子、粪肥中的卵孢子直接传到病田外，主要靠气流和灌溉水或雨水传播。

(III)OccurrenceRegularityOversummer:Inwinterraperegions,thepathogensoversummerasoosporesinthesoil,manure,andseedswiththediseasedresidues.Aftergerminationinautumn,theyinfecttheseedlings,andsporangiaareproducedonthespotsforsecondaryinfection.Overwinter:Inwinter,thediseasedoesnotexpandrapidlyandoverwintersinthediseasedleavesashyphae.Inthefollowingspring,theairtemperaturerises,andsporangiaareproducedtospreadbywindandraintoinfectleaves,stemsandcornerfruitsagain.Whenrapeentersthematuritystage,thediseasedpartsproduceoosporesagaintocauserepeatedre-infection.Long-rangespreadmainlydependsonoosporesmixedinseeds.Asforclosespread,oosporesmixedinseedsandmanurearemainlytransmittedbyairflowandirrigationwaterorrainwater,exceptthattheyaredirectlytransmittedtodiseasedfieldsthroughseedsandmanure.（三）发病规律该病发生与气候、品种和栽培条件关系密切气温8～16℃、相对湿度高于90%、弱光利于该菌侵染。长江流域油菜区冬季气温低，雨水少发病轻，春季气温上升，雨水多，田间湿度大易发病或引致薹花期该病流行。连作地、播种早、偏施过施氮肥或缺钾地块及密度大、田间湿气滞留地块易发病。

(III)OccurrenceRegularityTheoccurrenceofthediseaseiscloselyrelatedtoclimate,cultivarandcultivationconditionsItisconducivetothebacterialinfectionwhenthetemperatureis8~16°C,therelativehumidityisabove90%,andthelightisweak.IntherapeareaoftheYangtzeRiverBasin,theairtemperatureislowinwinter,withlessrain,andthediseaseisgentle;inspring,theairtemperaturerises,withmorerainandhighfieldhumidity,itiseasytocausethediseaseorcausethediseasetospreadduringtheboltingandfloweringperiod.Continuouscropping,earlysowing,excessiveapplicationofnitrogenfertilizerorpotassium-deficientplotsandplotswithhighdensityandmoistureretentioninthefieldarepronetothedisease.（四）防治技术

1、因地制宜种植抗病品种。如中双4号、两优586、新油9号、蓉油3号等。提倡种植甘蓝型油菜或浠水白等抗病的白菜型油菜。2、与禾本科作物轮作l～2年，或水旱轮作，可大大减少土壤中卵孢子数量，降低菌源。3、种子消毒播种前用25％甲霜灵可湿性粉剂按干种重量0.3％拌种。也可用50％福美双或75％百菌清可湿性粉剂拌种，药量为种量的0.4％。

(IV)ControlTechnique1.Plantdisease-resistantvarietiesaccordingtolocalconditions.SuchasZhongshuangNo.4,LiangyouNo.586,XinyouNo.9andRongyouNo.3.ItissuggestedtoplantBrassicanapusorXishuibaiandotherdisease-resistantcabbagerapes.2.Rotationwithpoaceouscropsfor1~2yearsorpaddy-uplandrotationcangreatlyreducethenumberofoosporesinthesoilandreducethepathogensource.3.Seeddisinfection:Beforesowing,mixtheseedswith25%metalaxylwettablepowderby0.3%ofthedryseedweight.Theseedscanalsobemixedwith50%thiramor75%chlorothalonilwettablepowder,andthedosageis0.4%oftheseedweight.

4、加强田间管理，做到适期播种，不宜过早。根据土壤肥沃程度和品种特性，确定合理密度。采用配方施肥技术，合理施用氮磷钾肥提高抗病力。雨后及时排水，防止湿气滞留和淹苗。发现病叶随时摘除，收获后搞好田园卫生。5、药剂防治，一般在3月上旬抽薹期，调查病情发生情况，当病株率达20%以上时，用烯酰吗啉、甲霜·锰锌、霜霉威盐酸盐、代森联等，一般隔7～10d喷1次，视病情防治2～3次。4.Strengthenfieldmanagementandsowseedsinduetime,whichshouldnotbetooearly.Determinethereasonabledensityaccordingtothesoilfertilityandvarietycharacteristics.AdoptformulafertilizationtechnologyandreasonablyapplyNPKfertilizertoimprovediseaseresistance.Drainwaterintimeafterraintopreventmoistureretentionandseedlingflooding.Removethediseasedleavesatanytime,andensurefieldhygieneafterharvest.5.Chemicalcontrol.Generall