Browsing by Author "SRINIVAS, K."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
ThesisItem Open Access BIO- EFFICACY OF SELECTED INSECTICIDES AGAINST RICE PEST COMPLEX WITH SPECIAL REFERENCE TO RICE LEAF FOLDER Cnaphalocrocis medinali's GUENEE(Professor Jayashankar Telangana State Agricultural University, 2001) SRINIVAS, K.; MADHUMATHI, T.The studies wereconducted both inthe laboratoryand field during kharif 2000 on the biology of rice leaffolder, Cnapha/ocrocis medina/is Gueneeand Bio-efficicacyofselected insecticidesagainstrice pestsand their effect on natural predators atAgricultural College, Bapatla. Female moth laid flat, oval eggs in groups and occasionally in singles on the undersurface ofleaves nearmidrib, The eggs measured 0.70 : 0.25mm‘in length with an average fecundity of 80 eggs. The larva had five instars which measured 2.35 i 0.65, 5.20 i 0.48, 10.80 i 0.38, 13.60 i 0.24 and 16.6 : 0.13mm in length. Full grown larva is greenish yellowand pupated insidethe leaffold and sometimes in between thestem and leafsheath. Pupa ofmaleandfemale measured 10.23i0.34 and 11.80:0.97mm length respectivelywith distinctsexual dimorphism, Theegg, larval, pre-pupal, pupal and adultmaleandfemale longevity periods were 4.7 +_0.46, 18.8 i 0.81, 1.5 i 0.5, 7.0 1 1.0, 3.5i0.5and8.8:0.98'days,respectively. Field studies on the bioefficacy of selected insecticides showed that after two sprays given at 30 and 45 days after transplantation, cartap hydrochloride4G @ 25 kg ha", ethofenprox 10EC @ 15ml l‘1 and acephate 758P @ 1.59 l'1 against leaf folder and carbofuran 36 @ 25 kg ha". fipronil 0.36 @ 25 kg ha‘1 and chlorpyriphos 1OG @ 10 kg ha‘1 against gall midge were effective. Studies on the effect of insecticides against natural predatory populations indicated that carbofuran 3G @ 25 kg ha“, azadirachtin 1500ppm @ 2.5ml and 5ml l'1 , ethofenprox 10EC @ 15ml l“, fipronil 0.3G @ 25 kg ha‘l, cartap hydrochloride 4G @ 25 kg ha'1 to spiders: cartap hydrochloride 4G @ 25 kg ha“, chlorpyriphos 1OG @ 10 kg ha" and azadirachtin 1500ppm @ 2.5 and 5rril l‘1 to coccinellids; azadirachtin 1500ppm @ 2.5 and 5ml I“, cartap hydrochloride 4G @ 25 kg ha". carbofuranto carabids; cartaphydrochloride4G@25kg ha". carbofuran BG @ 25 kg ha”. azadirachtin 1500ppm @ 2.5m l‘1 to damselflies and cartap hydrochloride 4G @ 25 kg ha", azadirachtin 1500ppm @2.5mlI". chlorpyriphos 1OG@10kgha'1todragonflieswererelatively safeastheyrecorded comparativelyless mortality while phenthoate50EC and BPMC 50EC against spiders and dragonflies; BPMC 50EC and ethofenprox 10EC againstcoccinellids; chlorpyriphos20EC, BPMC 50EC, ethofenprox 10EC against carabids and damselflieswere highlytoxic. Highest yields of52.59, 43.11 and 41.48 q ha'1 were obtained in plots treated with carbofuran BG, fipronil 0.3G and cartap hydrochloride 4G, respectively.ThesisItem Open Access RESPONSE OF SUNFLOWER(Helium/ms annuusL.)TO VARYING TW/CPE RATIOS IN SUMMER SEASON(Professor Jayashankar Telangana State Agricultural University, 1998) SRINIVAS, K.; PRAVEEN RAO, V.A fieldexperimentwasconductedonsandyloamsoilatCollegefarm,Acharya N.G.RangaAgriculturalUniversity,Rajendranagar,Hyderabadduring 1997—98summer seasontoinvestigatethe“Responseofsunflower(HeliantlzusannuusL.)tovarying IW/CPEratiosinsummerseason”. Thetreatmentsconsistedofdifferentirrigationschedulesbasedonirrigationwater depth (1W) : Cumulative pan evaporation (CPE) ratios viz., 0.6, 0.8, 1.0 and 1.2 throughoutthecr0plifeandtheircombinationsatvegetative andreproductivestages. Besidesthisanirrigationtreatmentbasedonschedulingirrigationsonlyatcriticalgrowth sub periods was included. Thus, constituted twelve treatments were laid out in a randomizedblockdesign withthreereplications. Thetest varietywasMSFH-8. The amountofwaterappliedateachirrigationwasequivalentto50mmdepth(1134litersper plot). Schedulingofirrigationsat 1.0IW/CPE (13)ratiothroughoutcroplife(whichrequired10irrigationsof50mmdeptheachat8daysinterval), 1.2 IW/CPE(L)ratio throughoutcroplife(whichrequired12irrigationsofSOmmdeptheachat6daysinterval) andcombinationof0.6+1.0(16),0.6+1.2(17),0.8+1.002;),0.8—1.2(19),1.0+1.2(110) lW/CPEratios(which required9-12 irrigationsof50mm deptheach withan irrigation interval of6—10days)wereon parand producedsigniticantlx Pig-her 31'.:1:1 itch-:11 lcz1i area/plant drymatteraccumulation/plant,capitulumdiameter totalnumberofseedsper plant,1000-seedweight seedyield/plant oilcontent,seedyield/haandtotaldrymatter/"ha incomparisonto0.6IIW/CPE(1;)ratiothroughoutthecroplife,0.8IW/CPE(1;)ratio throughoutthecroplifeandcombinationsof0.6+0.8(15)and0.8+0.6(In)IW/CPE ratiosandinigationsatcriticalgrowthstagesonly(112). ThecropETawasmaximum(489.4mm)intreatment1.2IW/CPEratiothroughoutcroplife(14)closelyfollowedby1.0+1.2(110)(486.5mm)and0.8+1.2(19)(478mm) IW/CPE ratios. While lowest ETa (259 mm) was recorded when irrigations were scheduledatcriticalgrowthstages(112). Ontheotherhand,wateruseefficiencywas highest(5.10kg/ha/mm)whenirrigationswerescheduledat0.8+1.0IW/CPEratio(13). As regardsto moistureextraction pattern cropplants in adequate soil moistureregimes [13(1.0IW/CPEratiothroughoutthecroplife),I4(1.2IW/CPEratiothroughoutthecroplife),16(0.6+ 1.0IW/CPEratio),17(0.6+ 1.2IW/CPEratio),18(0.8+ 1.0 IW/CPEratio),19(0.8+ 1.2IW/CPEratio)and110(1.0+ 1.2IW/CPEratio)treatments] extractedmoremoisturefrom0-40cmsoildepthincrement;whilecropplantsinrelatively drytreatments [11 (0.6 TW/CPE ratio throughoutthe crop life), 12 (0.8 IW/CPE ratio throughoutthecroplife),15(0.6+0.8IW/CPEratio),In(0.8+0.6IW/CPEratio),and112 (irrigationsatcritical grtstages)treatments] extractedbulkoftheirmoisture from lowerdepthsi.e.,20—60cm. Crop coefficients for sunflower ETa were developed based on open panevaporation methodandcalculation ofnet irrigationrequirementand gross irrigation requirement usingKcvalueswasdemonstrated. Theseasonalnetirrigationrequirement was 463.2 mm, while the gross irrigation requirement at field inlet and head works amountedto6617m3and 11580m3 respectively.Thepeakim'gationrequirementwas 4232In. ThecropyieldresponsetoseasonalETawasfoundtobe linearwithanR2of0.958. Seedyieldshowedsignificantpositivecorrelationwithplantheight,leafareaper plant,drymatterperplant,diameterofcapitulum,effectiveseedsperplant,totalnumberof seedsperplantandtestweight. Variationofplantwaterstressparametersviz,relativewatercontent,leafwaterpotential, diffusive resistance, transpiration rate andleaftemperature were largely a functionofwaterapplicationi.e.,IW/CPEratiosemployedduringthecropgrowingseason for scheduling irrigations. Seed yield and crop ETa showed significantly positive correlationwithrelativewatercontent,leafwaterpotentialandtranspirationrate,whileit was negativewithdiffusiveresistanceandleaftemperature.