《植物病虫害绿色防控技术》课件-四、甘薯病虫害绿色防控（双语）

四

甘薯病虫害绿色防控

IV

GreenPreventionandControlofSweetPotatoDiseasesandPests

一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot甘薯黑斑病

又称黑疤病，黑膏药、黑疮等，目前已成为我国甘薯产区危害普遍而严重的病害之一。据统计，我国每年由该病造成的产量损失为5％～10％，危害严重时造成的损失为20％～50％，甚至更高。此外，病薯中可产生甘薯黑疱霉酮等物质，人畜食用后，引起中毒，严重者死亡。Sweetpotatoblackspot,alsoknownastheblackscar,blackplaster,blacksore,etc.,hasbecomeoneofthecommonandseriousdiseasesinproducingareasofsweetpotatoinChina.Accordingtostatistics,theannualyieldlosscausedbythediseaseinChinais5%~10%,andthelosscausedbyseriousdamageis20%~50%orevenhigher.Inaddition,ipomeamaroneandothersubstancescanbeproducedindiseasedpotatoes,whichcancausepoisoninganddeathinseverecasesafterhumanandanimalconsumption.（一）症状

主要危害薯苗和薯块。苗期症状

受侵染的幼芽基部产生凹陷的圆形或梭形小黑斑，以后逐渐纵向扩大至3～5mm，严重时则环绕苗基部形成黑脚状。地上部病苗衰弱，矮小，叶片发黄，重病苗死亡。

(I)SymptomsItmainlyharmssweetpotatoseedlingsandtubers.SymptomsatseedlingperiodAtthebaseofinfectedseedlings,concaveroundorspindlesmallblackspotsappear,andthengraduallyexpandto3~5mmlongitudinally.Inseverecases,blackrootformaroundthebaseofseedlings.Theabovegroundpartofthediseasedseedlingisweakandshort,theleavesturnyellow,andtheseriouslydiseasedseedlingdies.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot生长期症状当病苗移栽到大田后，生长衰弱，叶片发黄脱落，遇干旱易枯死。病苗即使成活，结薯也少，产量极低。薯蔓上的病斑可蔓延到新结薯块上，多在伤口处产生黑色斑块。Symptomsatgrowthperiod

Whenthediseasedseedlingsaretransplantedtothefield,theirgrowthisweak,theleavesturnyellowandfalloff,andtheyareeasytodieincaseofdrought.Evenifthediseasedseedlingssurvive,therearefewpotatoesandtheyieldisextremelylow.Thespotsonthepotatovinescanspreadtothenewtubers,mostlyproducingblackspotsatthewounds.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot贮藏期症状病斑多发生在伤口和根眼上，初为黑色小点，逐渐扩大成圆形、椭圆形或不规则形膏药状病斑，稍凹陷，直径1～5cm不等，轮廓清晰。病部组织坚硬，可深入薯肉2～3cm，薯肉呈黑绿色，味苦。Symptomsatstorageperiod

Thespotsmostlyoccuronthewoundsandrootholes.Itisinitiallyblackdotsandgraduallyexpandsintoround,oval,orirregularplaster-likespots,slightlysunken,withadiameterrangingfrom1~5cmandaclearoutline.Thetissueoftheaffectedpartishard,andcanpenetrateintothesweetpotatoby2~3cm.Thesweetpotatopresentsblack-greenandtastesbitter.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot（二）病原甘薯长喙壳菌属子囊菌亚门长喙壳属甘薯黑斑病菌1.分生孢子2.厚垣孢子3.子囊壳4.子囊壳基部剖面5.子囊6.子囊孢子(II)EtiologyCeratocystisfimbriataEllis.etHalstedbelongstotheCeratocystisofAscomycotinaFungusofsweetpotatoblackspot1.Conidia2.Chlamydospore3.Perithecium4.Basesectionofperithecium5.Ascus6.Ascospores一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot（三）发病规律越冬：以子囊孢子、厚垣孢子和菌丝体在薯块或土壤中病残体上越冬。带菌种薯和秧苗是主要的初侵染来源，其次是带有病残组织的土壤和肥料。侵入途径：甘薯黑斑病病菌寄生性不强，主要由伤口侵染，也可从根眼、皮孔等自然孔口侵入。传播：分生孢子和子囊孢子在田间主要靠种薯、种苗、土壤、肥料和人畜携带传播。温湿度：土温在15～30℃适合发病，最适温度为25℃；甘薯贮藏期间，当温度高于15℃时利于发病，最适发病温度为23～27℃。

(III)OccurrenceRegularityOverwintering:Ascospores,chlamydospores,andmyceliumoverwinterontubersordiseasedresiduesinsoil.Theseedtubersandseedlingswithfungusarethemainsourcesofprimaryinfection,followedbysoilandfertilizerwithdiseasedandresidualtissues.Waysofintrusion:Thepathogenofthefungusofsweetpotatoblackspotisnothighlyparasiticandismainlyinfectedbywounds,andcanalsointrudebynaturalorificessuchasrootholsesandlenticels.Transmission:Conidiaandascosporesaremainlycarriedbyseedtubers,seedlings,soil,fertilizers,andhumansandanimalsinthefield.Temperatureandhumidity:Soiltemperatureof15~30°Cissuitableforthedisease,andtheoptimumtemperatureis25°C.Duringthestorageofsweetpotatoes,whenthetemperatureishigherthan15°C,itisconducivetothedisease,andtheoptimumtemperatureforthediseaseis23~27°C.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot

（四）防治技术

采取以清除初侵染来源为前提、精选无病种薯为基础、培育无病壮苗为中心、安全贮藏为保证，实行以农业防治为主、药剂防治为辅的综合防治措施。（1）清除侵染源

严格执行检疫制度，严禁从病区调运种薯、种苗。育苗时不用病土、旧床土垫苗床，更新苗床土壤；大田收获后，及时清除病源，集中将带病残体晒干焚烧或深埋。（2）建立无病留种田

选用无病薯苗栽插大田，采用高剪苗，结合药剂浸苗，或在春薯蔓上剪蔓栽插夏薯；留种地要选3年未栽种甘薯的地块，收获的种薯要单收、单运、单藏。（3）种薯的安全

薯块入窖后，初期应注意降温排湿，当气温下降时，应及时封窖防冻，严格控制窖温在10～14℃。黑斑病发生严重的地区，种薯入窖前，可用25%多菌灵可湿性粉剂250倍液浸种5min，凉干后再入窖。

(IV)ControlTechniqueComprehensivepreventionandcontrolmeasureswithagriculturalpreventionandcontrolasthemainstayandchemicalpreventionandcontrolasthesupplementshallbeimplementedonthepremiseofremovingtheprimaryinfectionsource,selectingdisease-freeseedtubersasthebasis,cultivatingdisease-freestrongseedlingsasthecenterandsafestorageastheguarantee.

(1)Removalofthesourceofinfection.Strictlyimplementthequarantinesystem,anditisstrictlyprohibitedtotransportseedtubersandseedlingsfromtheendemicarea.Whenraisingseedlings,donotusediseasedsoilandoldbedsoiltomattheseedbed,andrenewtheseedbedsoil.Afterharvestinginthefield,removethediseasesourceintime,andintensivelydry,burn,ordeeplyburythediseasedresidues.

(2)Establishmentofthedisease-freeseedfield.Selectdisease-freepotatoseedlingstoplantinthefield,usehigh-cuttingseedlings,soaktheseedlingswithchemicals,orcutthevinesonthespringpotatocranetoplantsummerpotatoes.Selectplotswheresweetpotatoeshavenotbeenplantedforthreeyearsastheseedfieldandharvestedseedtubersshouldbeharvested,transported,andstoredseparately.

(3)Safetyofseedtubers.Afterthetubersareputintothecellar,attentionshouldbepaidtocoolinganddehumidificationattheinitialstage.Whenthetemperaturedrops,thecellarshouldbesealedintimetopreventfreezing,andthecellartemperatureshouldbestrictlycontrolledat10~14°C.Inareaswithseriousblackspots,seedtuberscanbesoakedin1:250dilutionof25%carbendazimwettablepowderfor5minutesbeforebeingputintothecellar,andthenputintothecellarafterbeingcooledanddried.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot（4）培育无病壮苗

①精选种薯育苗时，做到种薯三选，即出窖时选，浸种时选，苗床排种时选。严格剔除病、虫、伤及受冻薯块。

②种薯消毒

种薯消毒处理可采用温汤浸种和药剂浸种。温汤浸种：薯块在51～54℃温水中浸10min，可杀死附着在薯块表面及潜伏在种皮下的病菌。由于种薯下水后要大量吸热降温，所以应将水温调节在56～58℃。药剂浸种：因地制宜地选用浸种药剂种类。可选用70%甲基硫菌灵可湿性粉剂800～1000倍液浸种10min；或50%代森铵200～300倍液浸种10min。浸种液一次配药可连续浸种薯10～15次。药剂浸种不仅防病效果好，而且还有促进出苗及生长的作用。

(4)Cultivationofstrongdisease-andpest-freeseedlings①Thereselectionofseedtubersshouldbecarriedoutforcarefulselection,thatis,selectionwhenleavingthecellar,selectionwhensoakingseedtubers,andselectionwhenseedbedseeding.Strictlyremovediseases,insects,injuries,andfrozentubers.②Disinfectionofseedtubers.Soakinginwarmwaterandchemicalscanbeusedforthedisinfectionofseedtubers.Soakinginwarmwater:Soakingtubersinwarmwaterat51~54°Cfor10mincankillpathogensattachedtothesurfaceofpotatoesandlatentundertheseedcoat.Sinceseedtubersneedtoabsorbalotofheatafterenteringthewater,thewatertemperatureshouldbeadjustedto56~58°C.Soakingwithchemicals:Selectthetypesofchemicalsaccordingtolocalconditions.Theseedscanbesoakedin1:800~1,000dilutionof70%thiophanate-methylwettablepowdersfor10min,orin1:200~300dilutionof50%ammoniumsulfatefor10min.Theseedtuberscanbecontinuouslysoaked10~15timesafterthesolutionispreparedonce.Chemicalsoakingnotonlyhasagooddisease-preventioneffectbutalsopromotesseedlingemergenceandgrowth.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot③加强苗床管理

育苗时尽量采用新苗床，旧苗床应清除全部旧床土，更换新土，并喷药消毒，且施用无菌净肥。④药剂浸苗

将薯苗捆成小捆，在药剂中浸秧苗基部，具有消毒防病作用。可用70%甲基硫菌灵可湿性粉剂800～1000倍液浸薯苗5min、50%多菌灵可湿性粉剂2500～3000倍液浸薯苗2～3min或10%双效灵水剂400～500倍液浸薯苗10min。（5）选用抗病品种

因地制宜选用抗病品种，目前生产上推广应用的抗病品种主要有苏薯8号、豫薯4号、渝苏303、渝苏153、鄂薯2号、冀薯4号等。（6）加强栽培管理

实行轮作倒茬，旱地种植3年以上轮作或旱地和稻田轮作。同时采用起垄栽培，合理施用肥水，增施不带病菌的有机肥，防止薯块开裂，及时防治地下害虫和田鼠。③Strengthenseedbedmanagement.Newseedbedsshouldbeusedasfaraspossibleduringseedlingraising.Alltheoldseedbedsoilshouldberemoved,replacedwithnewsoil,disinfectedbysprayingchemicals,andappliedwithsterilecleanfertilizer.④Seedlingssoakingwithchemicals.Bundlepotatoseedlingsintosmallbundlesandsoakthebaseofseedlingsinthechemicalfordisinfectionanddisease-prevention.Theseedlingscanbesoakedwith1:800~1,000dilutionof70%thiophanate-methylwettablepowderfor5min,1:2,500~3,000dilutionof50%carbendazimwettablepowderfor2-3min,or1:400~500dilutionof10%shuangxiaolingsolutionfor10min.(5)Selectionofdisease-resistantvarieties.Selectdisease-resistantvarietiesaccordingtolocalconditions.Atpresent,thedisease-resistantvarietiespopularizedandappliedinproductionmainlyincludeSushu8,Yushu4,Yushu303,Yushu153,Eshu2,Jishu4,etc.(6)Strengthencultivationmanagement.Croprotationshallbecarriedout,andcroprotationshallbecarriedoutindrylandformorethan3yearsorindrylandandricefields.Atthesametime,ridgingcultivationisadopted,fertilizerandwaterarereasonablyapplied,andorganicfertilizerwithoutpathogensisaddedtopreventtubersfromcrackingandpreventundergroundpestsandrodentsintime.一甘薯黑斑病绿色防控I.

GreenPreventionandControlofSweetPotatoBlackSpot

甘薯软腐病

俗称水烂病，为甘薯贮藏期的主要病害之一。该病发分布广泛，全国各甘薯生产区均有发生，常在贮藏期发生腐烂，造成不同程度的损失。（一）

症状识别

薯块变软腐烂，表面生有棉絮状灰白色菌丝体，后期上有黑色小点。切开病薯块，薯内呈淡褐色，维管束褐色较深，可流出汁水，有芳香酒味。二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo

Softrotofsweetpotato.Itiscommonlyknownaswaterrot,whichisoneofthemaindiseasesduringthestorageperiodofsweetpotatoes.ThediseaseoccurswidelyinallsweetpotatoproductionareasinChina,andoftenrotsduringstorage,causinglossestodifferentdegrees.(I)Symptomidentification

Thetubersbecomesoftandrotten,withcottonflocculentgrayish-whitemyceliumonthesurfaceandblackdotsonthelaterstage.Whenthediseasedtubersarecut,thetubersarelightbrown,andthevascularbundlesaredarkbrown,withsapflowingoutandthearomaofalcohol.甘薯软腐病为害薯块症状甘薯软腐疬为害薯块横切面症状SymptomsofTuberDamagedbySoftRotSymptomsofCrossSectionofTuberDamagedbySoftRot二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo根霉属（二）病原物分类地位：接合菌亚门根霉属；孢囊梗：直立，丛生于匍匐丝上，下端生有假根；孢子囊：球形，内有半圆形的囊轴及大量的孢囊孢子；孢囊孢子：单胞，褐色，椭圆形，表面有条纹；接合孢子：黑褐色，近球形，表面有刺状物。孢子囊（Sporangia）假根（Rhizoid）Rhizopus(II)PathogensTaxonomicstatus:RhizopusofZygomycotina;Sporangiophores:Erect,clusteredonstolons,withrhizoidsatthelowerend;Sporangia:Spherical,withsemicircularcolumellaandalargenumberofsporangiospores;Sporangiospores:Amerosporous,brown,oval,withstripesonthesurface;Zygospores:Black-brown,nearlyspherical,withspinesonthesurface.二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo接合孢子（Zygospore）二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo（三）

发生规律

该菌存在于空气中或附着在被害薯块上或在贮藏窖越冬，由伤口侵入。病部产生孢子囊借气流传播进行再侵染，薯块有伤口或受冻易发病。发病适温15～25℃，相对湿度76%～86%。

该病菌的腐生能力较强，寄主范围也较广，除甘薯外，还可为害多种作物的果实，花和贮藏器官。病原菌以孢子囊经气流及农事操作等传播，一般从薯块端部或其它部位的伤口侵入。

病害的发生与薯块的生活力强弱关系密切，薯块本身生活力旺盛，病害不会发生，只有薯块受冻后，生活力降低，病菌才容易侵入。薯块伤口多，带蔓贮藏等都有利于病害发生。(III)OccurrenceRegularity

Thefungusispresentintheairorattachedtotheinfectedtubersoroverwintersinthestoragecellarandinvadesfromwounds.Thesporangiaproducedbytheaffectedpartsaretransmittedbyairflowforreinfection,andtuberswithwoundsorfrozenarepronetothedisease.Theoptimumtemperatureforonsetis15~25°Candtherelativehumidityis76%~86%.Thepathogenhasastrongsaprophyticabilityandawidehostrange.Inadditiontosweetpotatoes,theycanalsodamagethefruits,flowers,andstorageorgansofvariouscrops.Thepathogenicbacteriaistransmittedbysporangiathroughairflowandagriculturaloperationsandgenerallyinvadesfromthewoundsattheendoftubersorotherparts.Theoccurrenceofthediseaseiscloselyrelatedtotheviabilityofthetuber.Thetuberitselfhasstrongviability,sothediseasewillnotoccur.Onlyafterthetuberisfrozen,theviabilityisreduced,andthepathogeniseasytoinvade.Tuberswithmanywoundsandarestoredwithvines,whichareconducivetotheoccurrenceofdiseases.二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo（四）

防治技术

1、适时收获，防止薯块受冻害

一般甘薯15℃以下即停止生长，9℃以下会遭受冷冻害，因此收获期掌握在旬平均气温在14～15℃时为宜，霜降前收获完毕，当天收获当天入窖，以免夜间遭受冷冻。

2、精选种薯入窖

凡带病、虫、伤及受冷、冻害薯块应严格剔除，运输过程中尽量减少伤口，保证贮藏质量。

3、选好窖址，做好旧窖消毒

提倡用新窖，旧窖要清理干净，或把窖内日土铲除露出新土，必要时用硫磺熏蒸，用硫磺15g/m3。消毒时应密闭两天，然后通气使用。

(IV)ControlTechnique1.Harvestintimetopreventtubersfromfreezingdamage.Generally,thegrowthofsweetpotatoesstopswhenthetemperatureisbelow15°C,andfreezingdamagewilloccurwhenthetemperatureisbelow9°C.Therefore,itisadvisabletocontroltheharvestperiodwhentheten-dayaveragetemperatureis14~15°C.AfterharvestingbeforeFrost'sDescent,putthepotatoesintothecellaronthesamedayofharvesttoavoidfreezingatnight.2.Puttingselectedseedtubersintothecellar.Alltuberswithdiseases,pests,injuries,coldinjuries,andfreezinginjuriesshouldbestrictlyremoved,andwoundsshouldbeminimizedduringtransportationtoensurestoragequality.3.Selectthecellarsiteandcarryoutdisinfectionfortheoldcellar.Itisrecommendedtouseanewcellar.Theoldcellarshouldbecleanedup,orthedailysoilinthecellarshouldberemovedtoexposethenewsoil.Ifnecessary,itshouldbefumigatedwithsulfurof15g/m3.Itshouldbesealedfortwodaysandthenventilatedforuse.二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo

4、加强贮藏期管理

应根据不同窖型掌握好窖内温、湿度及通气情况，甘薯入窖初期的15～20d内，薯块呼吸作用强，湿度大，应敞开窖门，散去水分，晚上或雨天应关闭窖门，待窖温稳定在10～14℃，应封闭窖门，冬季保持恒温，必要时应加覆盖物保温。春季气温回升后，随气温变化逐渐开窖通风，防止后期病害发生。4.Strengthenthemanagementofthestorageperiod.Thetemperature,humidity,andventilationinthecellarshallbewellcontrolledaccordingtodifferentcellartypes.Within15~20daysafterthesweetpotatoesareputintothecellar,thetubershavestrongrespirationandhighhumidity,sothecellardoorshouldbeopenedtodispersemoistureandthecellardoorshouldbeclosedatnightoronrainydays.Whenthecellartemperatureisstabilizedat10~14°C,thecellardoorshouldbeclosedandkeptataconstanttemperatureinwinter.Coveringsshallbeaddedforthermalinsulationifnecessary.Afterthetemperaturerisesinspring,graduallyopenthecellarforventilationwiththechangeoftemperaturetopreventdiseasesinthelaterperiod.二甘薯软腐病绿色防控II.

GreenPreventionandControlofSweetPotatoSoftRo（一）

发生与为害情况

甘薯麦蛾又名甘薯卷叶虫，属鳞翅目，麦蛾科。目前我国除新疆、宁夏、青海、西藏等地未见报道外，全国各地都有发生，且以南方各省发生较重。主要为害甘薯、蕹菜、山药、月光花、牵牛花等旋花科植物。

以幼虫为害，幼龄幼虫剥食叶肉，但不卷叶，幼虫稍大后，可以吐丝将叶卷起，幼虫在卷叶内啃食一面表皮和叶肉，留下另一面表皮，呈薄膜状，并将粪便排在卷叶内。此外，幼虫还能食害幼芽，嫩茎和嫩梢。发生严重时，大量叶片被卷缀，叶肉几乎被食尽，整片地呈现“火烧”现象，严重影响甘薯产量和品质。三甘薯麦蛾绿色防控III.

GreenPreventionandControlofSweetPotatoLeaf-folder

(I)OccurrenceandDamage

BrachmiamacroscopaMeyrick,alsoknownassweetpotatoleaf-folder,belongstoGelechiidaeofLepidopter.Atpresent,ithasnotbeenreportedinXinjiang,Ningxia,Qinghai,Tibet,andotherplacesinChina,butithasoccurredalloverthecountry,anditismoreseriousinsouthernprovinces.ItmainlydamagesConvolvulaceaesuchassweetpotato,waterspinach,yam,moonflower,andmorningglory.Thelarvaedamageplants.Younglarvaepeeloffmesophyllbutdonotrollleaves.Whenthelarvaeareslightlyolder,theycanspinsilktorolluptheleaves.Thelarvaenibbleononesideoftheepidermisandmesophyllintherolledleaves,leavingtheothersideoftheepidermisinafilmshape,anddischargefecesintherolledleaves.Inaddition,thelarvaecanfeedonyoungbuds,tenderstems,andshoots.Inseverecases,alargenumberofleavesarecurledupandthemesophyllisalmosteatenup,showinga"fire"phenomenoninthewholearea,whichseriouslyaffectstheyieldandqualityofsweetpotatoes.三甘薯麦蛾绿色防控III.

GreenPreventionandControlofSweetPotatoLeaf-folder三甘薯麦蛾绿色防控III.

GreenPreventionandControlofSweetPotatoLeaf-folder（二）形态识别1、成虫

体长5～7mm，翅展15～18mm，体黑褐色。前翅狭长，暗褐色或锈褐色，中室内有2个黑色小点，翅外缘有5个的小黑点。后翅较宽，淡灰色，缘毛较长。2、卵

长约0.6mm，椭圆形，表面有细的纵、横脊纹，初产时灰白色，后变为淡黄色，近孵化前一端出现小黑点。3、幼虫

老熟时体长18～20mm，头稍扁，黑褐色。前胸背板褐色，两侧具暗褐色倒“八”字形纹。中胸至腹部第2节背面黑色，以后各节乳白色，亚背线黑色，第2～6腹节每节两侧各有1条黑色斜纹。4、蛹

体长7～8mm，纺锤形，黄褐色。头钝尾尖，体上被细毛。臀棘末端有钩刺8个，呈圆形排列。

(II)MorphologicalRecognition1.Imago.Thebodylengthis5~7mm,thewingspreadis15~18mm,andthebodyisdarkbrown.Theforewingsarelongandnarrow,darkbrownorrustybrown,with2smallblackdotsinthemidcellsand5smallblackdotsontheoutermarginofthewings.Thehindwingsarewideandlightgray,andthemarginalhairsarelong.2.Egg.Theeggisabout0.6mmlongandoval,withfinelongitudinalandtransverseridgesonthesurface.Itisgrayishwhiteatthebeginningofdeliveryandthenturnslightyellow,withsmallblackspotsatoneendnearthehatchingend.3.Larva.Whenmature,thebodylengthis18~20mm,andtheheadisslightlyflatanddarkbrown.Thepronotumisbrown,withdarkbrowninverted"splayed"linesonbothsides.Thebackofthe2ndsegmentfromthemesothoraxtotheabdomenisblack,andthesubsequentsegmentsaremilkywhite,withblacksubdorsallines.Thereisablacktwillonbothsidesofeachofthe2ndto6thabdominalsegments.4.Pupa.Thepupais7~8mmlong,spindle-shaped,andyellowish-brown.Ithasablunttipandfinehairsonthebody.Thereare8hookspinesattheendofthebuttockspine,whicharearrangedinacircularshape.三甘薯麦蛾绿色防控III.

GreenPreventionandControlofSweetPotatoLeaf-folder三甘薯麦蛾绿色防控III.

GreenPreventionandControlofSweetPotatoLeaf-folder（三）

发病规律我国从北到南1年发生3～9代。在北方以蛹在残株落叶中越冬，而在南方以成虫在甘薯枯叶下、杂草丛中以及屋内阴暗处越冬。成虫昼伏夜出，有趋光性，喜食花蜜。成虫羽化后当天即可交配，次日晚产卵。多产卵于叶脉之间，少数产卵在嫩芽、嫩茎上，每头雌虫平均产卵100多粒。初孵幼虫在叶背啃食叶肉，2龄开始吐丝卷叶，3龄后食量增加，一条幼虫可卷食多片薯叶。4龄之后可将整叶对卷。食光叶肉或叶片．被害叶片大部分成灰色薄膜状或斑枯状，也有被食成较大孔洞的。田间幼虫密度大时，成火烧状团块。4龄之后的幼虫行动疾速活跃．触之即跳跃逃离，此阶段转叶为害频繁．一日当中可转叶3～6次。

(III)OccurrenceregularityThreetoninegenerationsoccurinayearfromnorthtosouthinChina.Inthenorth,itoverwintersaspupaeinstumpsandfallenleaves,whileinthesouth,itoverwintersasimagoesunderthedeadleavesofsweetpotatoes,inweedybushes,andintheshadowsofhouses.Theimagoesarenocturnalandphototaxisandliketoeatnectar.Theimagoescanmateonthesamedayaftereclosionandlayeggsthenextnight.Mosteggsarelaidbetweenveins,andafewlayeggsontenderbudsandstems.Eachfemalelaysmorethan100eggsonaverage.Thenewlyhatchedlarvaegnawonthemesophyllonthebackoftheleaves,spinandrolltheleavesatthesecondinstar,andincreasetheirappetiteafterthethirdinstar.Onelarvacanrollandeatmultiplepotatoleaves.Afterthefourthinstar,thewholeleavescanberolledinpairs.Eatingmesophyllorleaves.Mostofthedamagedleavesaregra