Sridevi, G.Supriya, G. B.2023-12-302023-12-302022-11-04https://krishikosh.egranth.ac.in/handle/1/5810205174Studies on life-fertility and insecticidal management of fall armyworm (FAW), Spodoptera frugiperda (J. E Smith) were carried out during 2019-20 and 2020-21. The life-fertility studies were conducted in the Department of Entomology, College of Agriculture, Rajendranagar, while the trial on bioefficacy of insecticides was carried out during rabi, 2019-20 and 2020-21 at the College farm. Studies on dissipation of selected insecticides were conducted at Pesticide Residues Laboratory, AINP on Pesticide Residues, PJTSAU, Rajendranagar, Hyderabad. The age specific survivorship of S. frugiperda on vegetative and reproductive parts of different host plants (7 no.) and artificial diet, revealed that the larval period of S. frugiperda on vegetative parts ranged between 11.97±0.015 days (tomato leaves) and 13.99±0.035 (paddy leaves) whereas on reproductive parts it ranged between 13.73±0.046 days (tomato fruits) and 14.92±0.072 (sorghum earheads) while on artificial diet, it was 14.84±0.139 days. The pupal period varied between 7.02±0.043 (paddy leaves) and 7.97±0.028 days (maize leaves) on foliage while it ranged between 7.05±0.052 days (sorghum earheads) and 9.87±0.122 days (maize kernels) on reproductive parts. The pupal period of S. frugiperda was recorded highest on artificial diet 8.86±0.170 days. The adult longevity ranged between 9.89±0.098 days (paddy leaves) to 13.84± 0.170 days (maize leaves) and 10.92±0.101 days (sugarcane setts) to 11.90±0.107 days (sorghum earheads) when S. frugiperda fed on vegetative and reproductive parts, respectively and on artificial diet it was 12.02±0.034 days. The total life cycle of S. frugiperda reared on vegetative (33.20±0.091 to 35.92±0.217 days) and reproductive parts (33.99±0.041 to 36.09±0.025 days) was significantly less than that on artificial diet (37.00±0.012 Name of the author : SUPRIYA G. B Title : “STUDIES ON LIFE-FERTILITY AND INSECTICIDAL MANAGEMENT OF FALL ARMYWORM” Degree to which it is submitted : DOCTOR OF PHILOSOPHY IN AGRICULTURE Faculty : AGRICULTURE Department : ENTOMOLOGY Chairperson : Dr. G. SRIDEVI University : PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY Year of submission : 2022 days). S. frugiperda when reared on maize leaves, sorghum leaves and artificial diet showed type-I survivorship curve, while on paddy and tomato leaves it was stair step, type-I. However, on sugarcane leaves, castor leaves, paddy panicles and sugarcane setts, the survivorship curve was type-II, stair step, type-III and type-II, respectively. The age specific survivorship of female S. frugiperda and its fecundity on different hosts were studied. The potential fecundity was significantly highest in artificial diet (4077.14±567.52 eggs) followed by maize leaves (2859.38±169.40 eggs)>castor leaves (2778.86±69.95 eggs)> maize kernels (1627.91±69.82 eggs)> sorghum leaves (1016.98±14.51 eggs). The various life parameters of S. frugiperda on different hosts revealed the suitability of host. The net reproductive rate (R0) was highest (947.43±0.479) in artificial diet, followed by maize leaves (707.57±0.584), maize kernels (496.88 ±2.127) and castor leaves (324.46±0.150), whereas, the highest mean generation time (Tc) was recorded on maize kernels (32.75±0.015 days) followed by artificial diet (32.03±0.012 days). The highest intrinsic rate of increase (rm) value was recorded highest on maize leaves (0.2193±0.00), followed by artificial diet (0.2140±0.00). The highest finite rate of increase (λ) recorded on maize leaves as (1.64±0.003 female offsprings/ female/day) followed by artificial diet (1.62±0.003 female offsprings/ female/day day), whereas highest weekly multiplication rates (WMR) value was recorded on maize leaves (4.64±0.006) followed by artificial diet (4.48±0.006) and castor leaves (3.84±0.006). Doubling time (DT) was recorded highest on maize leaves (3.17±0.006 days) followed by artificial diet (3.24±0.006 days), castor leaves (3.61±0.006 days) and maize kernels (3.67±0.006 days). The stable age distribution of S. frugiperda on different host plants indicated that the larval stage contributed maximum (92.60 to 97.49 %) compared to other stages to the total population, while the life expectancy on different hosts revealed that early stages recorded higher life expectancies than adult stages on all the hosts. The life table study of S. frugiperda on cotton leaves and bolls revealed that the larval duration on cotton leaves was 12.45±0.327 days and on bolls it was 12.47±0.306 days. The survivorship curve on cotton was type-II on both leaves and bolls. The life parameters like R0, Tc, λ, WMR and F2 females, were lower on cotton leaves compared to bolls. The per cent contribution of larvae to stable age was more than 90 per cent on cotton leaves and bolls, similarly, the larval and adult expectancy were significantly lower. The bio-efficacy studies revealed that spinetoram was the most effective insecticide against S. frugiperda with 97.61 per cent reduction in population followed by indoxacarb (91.09 %), spinosad (71.43%), emamectin benzoate (60.21%) and chlorantraniliprole (55.56 %). Among the selected insecticides, the mean highest yield of 3.34 t ha-1 was recorded from spinetoram treated plots followed by indoxacarb (3.09 t ha-1 ) and spinosad (2.45 t ha-1 ) which were found to be on par. The studies on dissipation pattern of selected insecticides in immature maize cobs revealed that indoxacarb persisted for 1.05 days while spinetoram dissipated below the limit of quantification (10 ppb), 2hrs after spraying.EnglishThesis