MADHUMATHI, T.SRINIVAS, K.2018-06-182018-06-182001D6506http://krishikosh.egranth.ac.in/handle/1/5810053803The 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.ennullThesis