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Rice (Oryza sativa L.) is a staple food crop supporting more than half of the global population. However, its productivity is severely constrained by insect pests, which cause significant yield losses at different crop growth stages. More than 100 insect species infest rice, but only about 15–20 species are of economic importance. Major pests include stem borers, planthoppers, leaf folders, gall midge, and gundhi bug. Effective pest management requires an integrated approach combining cultural, biological, mechanical, and chemical methods. This review highlights major insect pests of rice, their damage symptoms, and sustainable management strategies with emphasis on Integrated Pest Management (IPM).
Keywords: Rice; insect pests; IPM; biological control; sustainable agriculture; insectpests; biologicalcontrol; sustainableagriculture oliaoryzaeWood-Mason; isnowawide-spreadpest 1.Introduction causingseriouslossesinmanynewareaslikeU.P; Bi- Riceisoneofthemostimportantcerealcropsglob-
oliaoryzaeWood-Mason,isnowawide-spreadpest 1.Introduction causingseriouslossesinmanynewareaslikeU.P.,Bi- Riceisoneofthemostimportantcerealcropsglob- har,N.EasternstateofManipuretc. inadditiontoits ally and plays a critical role in food security. Insect severestatusnotonlyinkharifbutalsoinrabiseasons pestsareamajorbioticconstraintinriceproduction, incoastalareasofA.P.andKerala.Similarly,planthop- rankingsecondonlytoweedsincausingyieldlosses. persaswellasleaffolder,Cnaphalocrocismedinalis Thesepestsattackriceatallgrowthstages—fromnurs- Guenee which were of minor importance, assumed ery to storage—resulting in reduced yield and grain major pest status. Brown planthopper, Nilaparvata quality.Theintensificationofricecultivation,excessive lugensStalandwhitebackedplanthopper,Sogatella nitrogenfertilization,andindiscriminatepesticideuse furciferaHorvatharenowofseriousconcerninPun- haveledtopestoutbreaksandresistancedevelopment. jab,HaryanaandpartsofU.P.Theyhavebeenrecog- Therefore,sustainablepestmanagementstrategiesare nised as major pests responsible for significant de- essential.IntegratedPestManagement(IPM)andInte- clineinyieldofriceindifferentcroppingsystemzones gratedNutrientManagement(INM)arethetwopillars andareconsideredasnationalpests.Othersporadic ofcropmanagementthathasdirectinfluenceonthe pestsviz., ricehispa, DicladispaarmigeraOlivieroc- yieldandquality.Healthiersoilsproducecropsthatare curringinAndhraPradesh,HimachalPradesh,Bihar, lessdamagedbypests.Theinteractionsamongfertiliz- WestBengal,OrissaandNorthEasternregion,green ers,ricecultivars,andpestsmayhavedramaticeffects leafhopper,NephotettixvirescensDistantprevalentin onyield,yettheseinteractionsarepoorlyunderstood. Bihar,WestBengal,Assam,Orissa,MadhyaPradesh, Soilfertilitypracticescanaffectthesusceptibilityof AndhraPradeshandTamilNadu,gundhibug,Lepto- cropplantstoinsectpestsdirectlyorindirectly.Soils corisaspp.inuplandriceinUttarPradesh,Bihar,West withhighorganicmatterandactivesoilbiologicalac- Bengal,Orissa,MadhyaPradesh,Manipurandpartsof tivitygenerallyexhibitgoodsoilfertilityaswellascom- AndhraPradesh,climbingcutworm,Mythimnasepa- plexfoodwebsandbeneficialorganismsthatprevent rataWalkerinuplandricegrowingareasandswarming pestbuildup. Ontheotherhand,farmingpractices caterpillar,SpodopteramauritiaBoisduvalinlowlying thatcausenutritionimbalancescanlowerpestresis- riceinBihar,WestBengal,AssamandOrissahavebeen tance. Theresistanceortoleranceofplantstoinsect consideredregionallysignificant.Majorinsectpestsof pestsseemstobecloselyrelatedtovarioussoilprop- ricealongwithsymptomsofdamageweregivenbelow: erties.Asoil’sphysicalcondition,levelofcompaction, water-holdingcapacity,anddrainage,affectssoiland Brownplanthopper(BPH),NilaparvatalugensStal planthealth. Thechemicalaspectsofsoils(pH,salt Bothadultsandnymphssucksapfromthebaseofthe content,availabilityofnutrients,etc.)canaffectcrop tillers,resultinginyellowinganddryingoftheplants. health and pest susceptibility. Recent studies have Atearlystagesofattack,roundyellowishpatchesap- shownthatplantresistancetoinsectanddiseasepests pearwhichsoonturnbrownishduetodryingupofthe islinkedtooptimalphysical,chemical,and—perhaps plants.Thepatchesofinfestationspreadinconcentric mostimportantly—biologicalpropertiesofsoil(Altieri circleswithinthefieldandinseverecasestheaffected andNicholls,2003;Zehnderetal.,2007).Therearesev- fieldgivesaburntappearanceknownas’hopperburn’. eralstrategiesforimprovingthesoilhealthlikecrop Thehopperpopulationscanmultiplyveryfastandmi- rotation,growingofgreenmanures,covercrops,tillage grateoverlongdistancescausingwidespreadinfesta- practices,mulchesandcleancultivationthatalsohelp tioninshorttime.Apartfromcausingdirectdamage, inreducingtheinsectpestincidence.Thislecturein- BPHalsoactsasavectorofgrassystuntvirus. cludesmajorinsectpestsofriceandimpactoffertiliz- ers,organicmanuresonthesepestsandstrategiesto Whitebackedplanthopper(WBPH),Sogatellafur- beconsideredforenhancedsoilfertilityandeffective ciferaHorvath pestregulation.
WBPHisrelativelysmallerinsizecomparedtoBPHwith aconspicuouswhitespotondorsalthorax.Thenature 1.1 Insectpestscenarioinrice–presentstatus ofdamageofWBPHissimilartoBPH.Bothnymphsand Sincetheonsetofgreenrevolutioninriceinthecoun- adultssucktheplantsapfromphloemandcausedry- try,therehasbeenaconcomitantaccentuationand ingupofplants.UnlikeBPH,itdoesnotcausesudden tremendouschangeinthepestscenario.Amongthe andseverehopperburn.
majorpests,yellowstemborer,Scirpophagaincertu- Yellow Stem borer (YSB), Scirpophaga incertulas lasWalkerwhichwasnotknowninareaslikePunjab Walker and Haryana has assumed number one pest status, sometimesinflictingseverelosses.Gallmidge,Orse- Thestemborersattackricecropthroughoutthegrowth
Leaffolder(LF),CnaphalocrocismedinalisGuenee Leaffolderdamagewasfoundatallthestagesofcrop growth.Larvafoldstheleafandfeedsbyscrapingthe greenmesophylltissuefromwithinthefold.Thisfeed- Hopperburn ingresultinlongitudinalwhitestripesandunderse- Figure3.
vereinfestationwholefieldappearsscorched.Usually periodfromnurseryuptoharvest.Thedamageresults asinglelarvawasfoundineachfold.Thefoldingand incharacteristicsymptomsof’deadhearts’or’white feedingofleaffoldersaffectsthephotosyntheticability production. Theheavyapplicationofnitrogenfertil- izerrarelyaffectsinsectdirectly,however,itcanalter orchangemorphological,biochemicalandphysiologi- calcharactersofhostplantsandimprovenutritional conditionsforherbivores.Morenitrogenapplication wasforcedformoreoccurrenceofinsectpestsanddis- eases,especiallybrownplanthopper(BPH),leaffolder (LF),stemborer(SB),blast(Bl)andred-strippeddis- ease(RSD).Manyinsectspeciesexhibithighergrowth ratesanddecreaseddevelopmenttimeswhentheir Whiteear hostplantisfertilizedathighNlevels(e.g.,Fisherand Figure6.
Fiedler2000,SlanskyandFeeny1977,Tabashnik1982).
Theyfoundthattheaveragedensityofleaffolderlar-
inlarvaldensitywasduetothepositiveeffectofni- trogen fertilization on egg recruitment and survival Gallmidge,Orseoliaoryzae ofmedium-sizedlarvae. Thericeplantswithhighni- Themaggotofricegallmidgeentersinsidetheyoung trogenwerepreferredtofeedingandovipositionby riceplantandstartsfeedingongrowingportions.As Brownplanthopper(BPH).Plantswithhighnitrogen aresult,themeristematictissuegrowsandencloses contenthadhighfeedingratesandhoneydewexcre- thefeedinginsectinside.Themeristematictissueasit tion,lessprobingbehavior,highersurvivalrates,fe- grows,turnsintoapalegreentubularstructurecalled cundity and oocytes production and high tendency “silvershoot.”Thelarvaepupatesinsidethesilvershoot for outbreak of BPH (Cheng, 1971; Lu et al, 2004 & and emerges as adult from the top portion of silver 2005). Kannoetal(1977)monitoredthefeedingac- shoot.Thedamagedtillerdoesnotbearpanicle.The tivityofBPHusingtheisotopemarkof32Pandfound cropundersevereinfestationisstuntedwithmorenu- thatthefeedingamounts,honeydewexcretionandni- meroustillers.
trogencontentinthebodyofBPHonhighnitrogen Influenceoffertilizersoninsectpests plantswereincreasedby3-7,7and2-3times,respec- tively.Thewatercontent(WC)andrelativewatercon- Nutritionmanagementisoneofthemostimportant tent(RWC)significantlyincreased,whiletheamount practices for high production system, but nutrition ofsapflowedreducedstatisticallywiththeincrease managementmayaffectresponseofricetopests,as innitrogencontentofriceplants.However,theRWC wellasdevelopmentpatternofpestpopulationsdue inricetreatedwithhighnitrogenfertilizerdrastically tothechangeofenvironments.Theunderstandingof decreased due to the injury by BPH nymphs, while impactsofnutritionmanagementoninteractionsbe- thereducedsurvivaldurationwiththeincreaseofni- tweenriceandpestsisabasistostimulatehighyield trogen content was recorded. This might be one of productionsystem.Mostpestmanagementmethods thekeyfactorsforenhancingthesusceptibilitytoBPH usedbyfarmerscanbeconsideredassoilfertilityman- damageinriceplantssuppliedwithnitrogenfertilizer agementstrategiesandviceversa.Developmentoffer- (Luetal,2004).Nitrogenfertilizationalsosignificantly tilizerresponsivehighyieldingvarietieshasresultedin increasedthepopulationsofWBPH,GLH,andsmall theindiscriminateuseoffertilizersespeciallynitroge- brown planthopper ((Hu et al, 1986; Ma Lee, 1996). nousfertilizers.Applicationofthesefertilizershaslong However,MaandLee(1996)foundthatGLHpopulation termeffectsonthegrowthoftheplantwhichinturnaf- didnotincreasewithhighernitrogenlevelsinfieldsat fectsthepestpopulationdynamicsinriceecosystems. latertransplantingtimes.Thedeadheartsandwhite EffectofNitrogenoninsectpestsofrice heads caused by Yellow stem borer (YSB) increased Nitrogenisthemostessentialmineralnutrientforplant withhighernitrogenlevels(Yein Das,1988). Similar growthanddevelopmentandpropernitrogenman- effectsofnitrogenontheincidenceofStriped stem agementisessentialinintensiveagricultureforplant borer(SSB),Chilosuppressalishadalsobeenobserved (Tan,1986).Theapplicationofnitrogenfertilizercan Plant resistance to pests depends on the age and increase the succulence in stems and leaves, which growthoftheplantwhichisassociatedtothephys- can lead to greater stem borer attack, higher larval iology of the plant directly. Thus any factor that af- weightsandshorterthedevelopmentaltime.Liuand fectsthephysiologyoftheplantlikefertilizationhas Qin (1997) reviewed the population of YSB and SSB beenshowntoaffectallthreecategoriesofresistance inChinaandfoundthattheratesofdamage, densi- viz.,non-preference,antibiosis&tolerance.Fertiliza- ties, and the weight and sizes of larval body of SSB tionalsocauseschangesingrowthrates,sizeofplant increasedsignificantlywiththeincreaseinnitrogen, parts,prolongedvegetativestage,acceleratedorde- whilethenitrogencontentofriceplantwasakeyfactor layedmaturity,changeinfloweringetcwhichindirectly affectingthediapauseofYSBlarvae.However,whorl influencesthegrowthanddevelopmentofinsectpests. maggotandricethripsincidencewasnotincreased Effectsofsoilfertilitypracticesonpestresistancecan withincreaseindosesofnitrogen.
bemediatedthroughchangesinnutritionalcontent incrops. TheresponsesofBPHtonitrogendiffered Effectofphosphorousoninsectpests onricevarietieswithdifferentresistancelevels.Little Phosphorousfertilizerdidnotaffectricegrowth,but differencesinhoneydewexcretion,survivalrateand improves root development resulting which in turn population built-up of BPH were found on resistant increasestoleranceforrootpests,suchasrootwee- ricevarietiesat320kg/haand160kg/hanitrogenrates. vil,Echinocnemusoryzae(TirumalaRao,1952).There ThedamagesonresistantvarietyIR26byBPHwere wasnodifferenceinplantheight,numberoftillers/ notaffectedapparentlybynitrogenapplications,but squarefootatvariousP2O5levels.OnlytheSPADindex onsusceptiblevarietyKaoshenyu12thedamageswas wasrespondedtoP2O5levels,higherdoseofphospho- obvious. The BPH weights, feeding rates and popu- rousmadethericeleavesgreenerthanascomparedto lationgrowthincreasedwithnitrogenapplicationon control(nophosphorousapplication).Applicationof IR26,UtriRajapanandTriveni.Populationgrowthof phosphorousfertilizers(0–60kg/ha)didnotaffectthe BPHincreasedthreefoldonresistantvarietiesIR26and developmentandoutbreakofpests.However,applica- UtriRajapan,andtwofoldonmoderatelyresistantvari- tionof40kgP2O5resultedinlowstemborerdamage etyTriveni,withoutantibiosis(HeinrichsandMedrano, ascomparedtoothertreatments(chauetal,2003). 1985).Atthesamerateofnitrogenfertilizer,moreBPH adultswerelocatedonsusceptiblevarietiesthanon Effectofpotassiumoninsectpests resistantones(WangandWu,1991).
Lowestleaffolderinfestationandwhiteearincidence Soilnutrientavailabilitynotonlyaffectsthedegreeof wasrecordedathigherdosesofpotassium(100kg/ha). damagetoplantsbyherbivoresbutalsotheabilityof Similarlyearheadbugandbluebeetledamagewas plantstorecoverfromsuchdamage.Theadditionof foundlowathighdoseofK(Kulagodetal,2011).Kap- Nstimulatestillerproduction,whichhelpsriceplants plicationsmaysuppresspestsbyloweringplantsugar compensateforearlystemborerdamage(Rubiaetal andaminoacidlevels,promotingthickercellwallsand 1996).Similarly,plantswithhighNcontenthaveanim- increasingsiliconuptake(Baskaran,1985). provedabilitytocompensateforplanthopperfeeding (RubiaSanchezetal1999).
Effectofbalanceduseoffertilizers Gururajkattietal(2004)reportedlowestwhiteeardam- Effectoforganicmanuresoninsectpests ageaswellasleaffolderdamageatrecommendedlev- Useoforganicmanures,eitheraloneorincombination els of N, P and K. Studies in India, China, Indonesia withfertilizersisincreasingdaybydayinriceproduc- PhilippinesandVietnamfoundlowerinsectpestinci- tion. Inadditiontoimprovingthesoilfertilitystatus, denceinfieldswithsitespecificnutrientmanagement these organic manures may also affect insect pests. ascomparedtofarmersfertilizerpractices(Stacruz Theorganicmanurescreateapartialnitrogenstress etal,2001;Samiayyanetal,2000).Minorplantnutri- uptocertainperiodwithoutanynegativeeffectson ents,suchassiliconandzinc,canalsocontributeto cropgrowthandthusinduceresistancethroughintrin- pestsuppression.Intheproperquantities,siliconcan sicproductionofdefensecompounds,whichdeterthe increasetheresistanceofriceplantstoplanthoppers, pestattack.Thelownitrogencontentinplantsdueto andstemborers(Changetal2001,KimandHeinrichs organicmanuresleadstoincreasedphenols,tannins 1982,Pathaketal1971,Prakash1999). Zincapplica- andligninsthatmaketheleaftoughnessandproduc- tionsreportedlyminimizedamagebyElasmopalpus,a tionofmorecellwallrelatedstructuralcompounds stemborerofdrylandrice(Reddy1967).
Soilfertility&plantresistancetoinsectpests Theorganiccropshavebeenshowntobemoretolerant Pest ScientificName DamageSymptoms ManagementPractices Pheromonetraps, Deadhearts, YellowStemBorer Scirpophagaincertulas Trichogrammarelease, whiteearheads need-basedinsecticides Resistantvarieties, BrownPlanthopper Nilaparvatalugens Hopperburn,wilting avoidexcessnitrogen, imidaclopridspray Cnaphalocrocis Leaffolding, Lighttraps,biologicalcontrol, LeafFolder medinalis reducedphotosynthesis neemspray Resistantvarieties, GallMidge Orseoliaoryzae Silvershoots timelyplanting Manualremoval, RiceHispa Dicladispaarmigera Whitestreaksonleaves insecticidespray GundhiBug Leptocorisaacuta Chaffygrains,badodor Netting,malathionspray
Pest Stage ETL YellowStemBorer Vegetative 5%deadhearts YellowStemBorer Reproductive 2%whiteearheads BrownPlanthopper Allstages 10insects/hill LeafFolder Vegetative 2damagedleaves/hill GallMidge Tillering 5%silvershoots GundhiBug Milkystage 1bug/panicle aswellasresistanttoinsectattacksandorganicriceis mologyprogramrevealedthattheleaffolderdamage, reportedtohavethickercellwallandlowerlevelsof white ears by stem borer and BPH population were freeaminoacidthanconventionalrice.Surekhaetal lowinvermicompostappliedplotsfollowedbyFYMap- (2010)reportedthat,thewhiteearsanddeadhearts pliedplots.Neemcakeandkaranjcakeappliedplots inricewereslightlymoreininorganictreatmentscom- recordedlowpestincidencefollowedbyvermicompost paredtoorganics.Outbreakofstemborerinricecrop appliedplots(AICRIPProgressreport2008-2010). wasreportedtobelowwithorganicscomparedtosyn- Effectofpesticideapplicationsonsoilfertility theticinorganicfertilizers(LuongandHeong, 2005). Thereisalsoevidencethatcertainpesticidescanre- Significantly lowest percent of silver shoots was re- ducesoilfertility.Differentpesticideswillincreaseor portedwhennutrientsweremetthroughorganicsirre- decreaseammonification,nitrification,denitrification, spectiveofplantprotectionmeasures.Lowincidence andnitrogenfixation.Someinsecticides,suchaslin- ofinsectpestssuchasplanthoppersandleafhoppers dane(HCH)andchlorpyriphos, increaseextractable was observed in organically farmed rice fields com- ammoniuminfloodedsoils.Malathionandparathion, paredtotraditionalfields(Hidaka;1997;Kajimuraet organic phosphate insecticides, inhibit the activity al.,1993,andKajimura,1995).Surekhaetal(2010)also of soil urease under flooded conditions. The ef- reportedmorepopulationsofnaturalenemiessuchas fectsofpesticidesonnitrogentransformationscanbe Platygasteroryzae,miridbugsandspidersinorganic temperature-dependent.HCHappliedincombination treatmentscomparedtoinorganics.Hesleretal(1993) withcarbofuranresultnitrificationinfloodedsoils.Cer- andLouisetal(1993)reportedsignificantlyabundant tainpesticidesinhibitdenitrificationinirrigatedsoils. populationsofpredatorslikegiantwaterbugs,back CarbofuranstimuatesnitrogenfixationofNostocmus- swimmers and diving beetles in organic fields. The coruminliquidcultureatlowconcentrationsbutin- densityofimmigrantsofthericeplanthopperspecies hibitsNfixationathighconcentrations(RayandSethu- Sogotellafurciferawassignificantlylowerandtheset- nathan1988).Applicationoftriazophosresultedinthe tlingrateoffemaleadultsandsurvivalrateofimmature reductionofNandPcontentsandincreaseinKand stagesofensuinggenerationsweregenerallylowerin Zninricefoliageregardlessofcultivarsandnutrient organiccomparedtoconventionalricefield.Luongand levels.
Heong,(2005)opinedthattheorganicsormanuresaf- fectedriceplantgrowthandminimizedtheoutbreak EffectofSoilfertilitymanagementpracticesonin- ofbrownplanthopper.Amulti-locationstudyoneffect sectpests oforganicmanuresoninsectpests’underAICRIPento- Anumberofsoilfertilitymanagementpracticeslike Pest Insecticide Dose Remarks StemBorer Chlorantraniliprole18.5SC 150ml/ha ApplyatETL BPH Imidacloprid17.8SL 100ml/ha Avoidrepeateduse LeafFolder Flubendiamide20WG 50g/ha Sprayatearlystage Hispa Quinalphos25EC 1000ml/ha Uniformcoverage GundhiBug Malathion50EC 1000ml/ha Sprayatmilkystage
Agent TargetPest Application Trichogrammajaponicum Stemborer Release50,000/haweekly Cyrtorhinuslividipennis Planthoppers Conservationbiologicalcontrol Beauveriabassiana Variouspests Spray5g/litre Metarhiziumanisopliae Planthoppers Sprayformulation Neemoil(Azadirachtin) Generalpests 3-5ml/litrespray croprotation,covercrops,tillagepractices,greenma- 2.3 White-backed Planthopper (Sogatella fur- nuresandapplicationofcompostandotherorganic cifera) manureshavegreatimpactoninsectpestswherein • Causessapsuckingandtransmitsviraldiseases mostofthesepracticesbreakstheirlifecycle,creates unfavorableenvironmentforpestmultiplicationand 2.4 RiceLeafFolder(Cnaphalocrocismedinalis) exposethemtonaturalenemiesleadingtolowpest • Larvaefoldleavesandfeedonchlorophyll damage.
• Reducesphotosyntheticarea Theoryoftrophobiosis 2.5 RiceGallMidge(Orseoliaoryzae) Trophobiosis is derived from two Greek roots – • Causes“silvershoots”or“onionleaf”symptoms trophikos (nourishment) and bio- sis (life): "the re- lationshipsbetweenplantandparasiteareprimarily 2.6 RiceHispa(Dicladispaarmigera) nutritional"Chaboussou,p.206).Accordingtothetro- • Scrapesleafsurfaceleadingtowhitestreaks phobiosistheory,itisnutrientdeficienciesandimbal- ancesthatleadtopestanddiseaseoutbreaks,andthat syntheticpesticidesandfertilizerscancausesuchde- 2.7 GundhiBug(Leptocorisaacuta) • Suckssapfromdevelopinggrains ficienciesandimbalances. Accordingtothistheory, • Causeschaffygrainsandbadodor pestscanonlysurviveonplantsthathaveanexcessive Thesepestsarewidelyreportedaseconomically levelofsolublenutrientsintheirsaportissues,such importantacrossrice-growingregions asaminoacids,sugars,nucleotides,minerals.Theex- cess can be due to inhibition of proteosynthesis, to predominanceofproteolysisoverproteosynthesisor 3.YieldLossesDuetoInsectPests toexcessiveproductionofaminoacids.Inhibitioncan Yieldlossesvarydependingonpestspecies,infestation becausedbypesticidesorbyunbalancednutrition. level,andenvironmentalconditions.Inseverecases, Excessiveproductionofaminoacidscomesfromover- lossescanreach30–70%,particularlyduetoplanthop- supplyofnitrogenfromsolublefertilizers. persandstemborers.Pestpopulationdynamicsfluc- tuateseasonallyandgeographically.
2.MajorInsectPestsofPaddy Cross-ReferencingNote 2.1 YellowStemBorer(Scirpophagaincertulas) AsshowninFigure1,insectpestsundergocomplete • Damage symptoms: Dead hearts (vegetative metamorphosis, which is crucial for timing control stage),whiteearheads(reproductivestage) measures.Figure2illustratestheintegratedapproach • Natureofdamage: Larvaeboreintostemsand required for sustainable pest management in rice feedinternally ecosystems.Thefirstborerresistantvariety‘IR-20’of ricewasdevelopedbycrossingTKM-6(highlyresistant 2.2 BrownPlanthopper(Nilaparvatalugens) donor)xTN-1. Thisvarietyismoderatelyresistance • Damagesymptoms: Hopperburn,plantwilting tostripedricestemborer(Chilosuppressalis)andyel- • Importance: Major pest causing severe out- lowstemborer(S.incertulas)ofrice,besidespossess- breaksinAsia ingresistancetogreenleafhopper(Nephotettixspp.), Pest Stage ETL YellowStemBorer Vegetative 5%deadhearts YellowStemBorer Reproductive 2%whiteearheads BrownPlanthopper Allstages 10insects/hill LeafFolder Vegetative 2damagedleaves/hill GallMidge Tillering 5%silvershoots GundhiBug Milkystage 1bug/panicle
Pest Insecticide Dose Remarks StemBorer Chlorantraniliprole18.5SC 150ml/ha ApplyatETL BPH Imidacloprid17.8SL 100ml/ha Avoidrepeateduse LeafFolder Flubendiamide20WG 50g/ha Sprayatearlystage Hispa Quinalphos25EC 1000ml/ha Uniformcoverage GundhiBug Malathion50EC 1000ml/ha Sprayatmilkystage positsofsilicashowedtolerancetosomeborerspecies (Scirpophagaspp.andChilospp.)ofthecropasthese wornoutmandibleoftheinsects.
4.Conclusion Insectpestsremainamajorchallengeinriceproduc- tion,significantlyaffectingyieldandquality.Sustain- ablemanagementthroughIPMisthemosteffective approachtomitigatepestdamagewhileensuringenvi- ronmentalsafety.Futurestrategiesshouldfocusonin- Generalizedlifecycleofmajorinsectpests tegratingadvancedtechnologieswithtraditionalprac- Figure11.
inpaddyshowingegg,larva,pupa,andadultstages. tices to achieve long-term pest control and food se- curity.Todate,theapplicationofthescienceofpest nutrientinteractionsonriceconsistsofsimplerecom- mendationstosplitnitrogenapplications,plowstraw intothesoiltoincreasesiliconuptake,applyKduring planthopperoutbreaks,orapplyNtopromoterecov- ery following stem borer and defoliator damage, to giveafewexamples(Litsinger1994,Peng1993).While useful,thesesortsofunquantifiedrecommendations fallshortofgivingfarmersthetoolsnecessarytoma- nipulatepestpopulationsthroughnutrientmanage- ment.Furthermore,theliteratureisfullofcontradic- toryimplicationsforthemanipulationofsoilnutrients
themmoreattractivetostemborers(SekoandKato 1950).Ontheotherhand,theadditionofNstimulates tungrovirus,bacterialleafblightandseveralracesof tillerproduction,whichhelpsriceplantscompensate blast.Co-4varietyofcowpeahavingcharactersofpod forearlystemborerdamage(Rubiaetal1996).Plan- formationinwidercluster,wideranglebetweenthe thopperincidenceisincreasedbyNapplications(Cook podsandpeduncleandthickpodwallwasfoundto andDenno1994,Uthamasamyetal1983),butplants behighlyresistanttospottedpodborer(Marucates- withhighNcontenthaveanimprovedabilitytocom- tulalis).SugarcanevarietieslikeCo-62207,withahigh pensateforplanthopperfeeding(RubiaSanchezetal spinedensityonthelowerleafsurfaceormid-ribwere 1999).Theseapparentcontradictionsresultfromsev- foundtobelesssusceptibletoattackbythesugarcane eralfactors:mostofthestudiesareconductedonone topborer(S.nivella).Ricevarietiescontaininghighde- orafewcultivars,soilpropertiesarerarelyconsidered, Agent TargetPest Application Trichogrammajaponicum Stemborer Release50,000/haweekly Cyrtorhinuslividipennis Planthoppers Conservationbiologicalcontrol Beauveriabassiana Variouspests Spray5g/litre Metarhiziumanisopliae Planthoppers Sprayformulation Neemoil(Azadirachtin) Generalpests 3-5ml/litrespray
Crop Insect-pest Cultivars Deccan101&103;Ganga4,5,7&9; 1.Maize (a)Stemborer(Chilopartellus) Gangasafed-2etc.
2.Rice (a)Brownplanthopper(Nilaparvatalugens) Manasarowar,Bhadra,Joyti,CO-42etc. IR-36,Surekha,Lakshmi,Kunti,Shakti, (b)Gallmidge(Orseoliaoryzae) Rajendradhan,CAUS-1etc.
(c)Greenleafhopper(Nephotettixvirescens) IR-20,IET7301,IET7302,IET7303,Vanietc. (d)Yellowstemborer(Scirpophagaincertulas) Ratna,IET-3093,IET-2845,IET-2812,Soketetc. (e)Multipleresistantlines PTB12,PTB20,PT321,H-4etc.
(stemborer,leaffolder,thrips,bluebeetleetc.) andmostoftheresearchisdoneunderartificialcon- Gopalan,M.(1983).Theeffectofcarbofuranand ditionsinwhichnaturalenemiesandothercontribut- nitrogenonleaffolderincidence. IRRN, 8,13–14. ingvariablescannotaffecttheresults.Thereisaneed 7. Bhaskaran, P. (1985). Potash for resistance to todescribethecombinationsofsoilnutrientmanage- insectpests. JournalofPotassiumResearch, 1, mentandcultivarchoicesthatencourageordiscour- 81–94.
ageyieldlossfromdamagebykeyricepests.Itisalso 8. Chaboussou, F. (1985). Healthy plants: A new essentialtodevelopnutrientmanagementrecommen- agriculturalrevolution (Englishtrans.2004).Jon dationsthatpromotebettercompensationforandbet- Carpenter,Charlbury,UK.
terhostplantresistanceagainstpestdamageinnew 9. Gahn,G.C.,Sanchez,E.R.,&Cox,P.G.(2001). andpopularricecultivars.Now,thetimehascomefor Thequestforconnections:Developingaresearch integratingpestandnutrientmanagementstrategies agendaforintegratedpestandnutrientmanage- byimprovingthematchbetweenINMandIPMrecom- ment (DiscussionPaperNo. 42). International mendationsforricesothatfarmerscanstrikeabalance RiceResearchInstitute,LosBaños,Philippines. betweenapplyingenoughfertilizertoincreaseyields 10. Katti, G., Jotimani, R., Padmavathi, C., Pasalu, withoutincreasingpestdamage.
I.C.,Prasad,J.S.,&Krishnaiah,N.V.(2006,Oc- tober9–12). Effectoforganicmanuresonpest incidenceinrice [Posterpresentation].2ndInter-