Browsing by Author "Visalakshi, A"
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ArticleItem Open Access Biology of Gynaikothripskarnyi Bagnall,the marginal gall forming thrips of Pepper(Kerala Agricultural University, Vellanikara, 1967) Visalakshi, A; Joseph, K V; KAUArticleItem Open Access Biology of the Pepper Top Shoot Borer Laspeyresia hemidoxa Meyr. (Eucosmidae:Lepidoptera)(Kerala Agricultural University, Vellanikara, 1964) Visalakshi, A; Joseph, K V; KAUArticleItem Open Access Control of major pests of copra with phosphine fumigation(Kerala Agricultural University, 1998) Nalinakumari, T; Visalakshi, A; Mammen, K V; KAUArticleItem Open Access Degradation of mancozeb residues in pepper and the effect of processing on the removal of residues(Kerala Agricultural University, 1997) S Naseema Beevi; Thomas Biju Mathew; Visalakshi, A; Nalina Kumari, T; KAUArticleItem Open Access Dissipation of endosulfan in cowpea(Kerala Agricultural University, 1997) Naseema Beevi, S; Thomas Biju Mathew; Visalakshi, A; KAUIn an experiment to study the dissipation of endosulfan in cowpea pods following application @ 0.07 and 0.14 per cent at flowering and paid formation stage, the residues dissipated below detectable level on 15th day in the lower dose while 0.3 mg kg'1 could be detected in the higher dose. A waiting period of 2.85 and 5.21 days are fixed for the lower and higher dose respectively. Washing of green pods removed 39.78% of the initial deposit while washing followed by cooking removed up to 67.93% in the lower dose.ArticleItem Open Access Dissipation ok quinalphos and monocrotophos residues in cardamom capsules(Kerala Agricultural University, 1998) Thomas Biju Mathew; Visalakshi, A; Naseema Beevi, S; Rajan Asari, P A; Rajagopal, B; KAUThe paper describes the results of a field experiment conducted in the Cardamom Research Station, Pampadumpara, to study the dissipation of two insecticides used for controlling cardamom thrips and to fix their waiting periods. The results showed that the residues of quinalphos reached below the tolerance limit of 0.25 ppm within 23 to 24 days in fresh cardamom and within 20 to 21 days in cured cardamom. The corresponding periods for monocrotophos did not differ between fresh and cured cardamom (22 to 23 days) because of the systemic nature of the residues.ArticleItem Open Access Effect of phorate on growth characteristics and nitrogen contents of cowpea plants(Kerala Agricultural University, 1980) Visalakshi, A; Nair, M R G K; KAUStudies were made on the effect of phorale applied as granule with seeds treated/untreeted with Rhizobium on growth characterstics and total nitrogen contents of cowpea. In rhizobium treated plants, plant height and root length were significantly increased due to phorate treatment while the other factors such as fresh and dry weights of plants and TNC were increased only at 2 kg ai/ha level. In cowpea plants not treated with Rhizobium the height of the plant and TNC were significantly increased in general by phorate application.ArticleItem Open Access Effect of phorate on rhizobial nodulation in cowpea(Kerala Agricultural University, 1981) Visalakshi, A; Nair, M R G K; Aiyer, R S; KAUStudies were made on the effect of phorate granules applied along with seeds at the time of sowing on nodulation in cowpea treated with Rhizobium a compared to nodulation in untreated seeds. In Rhizobium treated plants, phorate caused suppression of nodule development and increase In nodular size, fresh weight and dry weight. In plants untreated with Rhizobium, phorate suppressed nodule formation in the roots and stimulated nodule size and fresh wieght.ThesisItem Open Access Factors responsible for the population buid up of rice bug, Leptocorisa acuta Thunb and the control of the pest(Department of Entomology, College of Agriculture, Vellayani, 1986) Krishna Kumar, R; KAU; Visalakshi, AThe rice bug Leptocoria acuta Thunb, was reared on the rice varieties Jaya, Jyothi, Triveni, Pavizham and Karthika in order to study the effect of varieties on the insect's biological features. Statistical analysis of the data obtained showed that varieties have no significant influence on the biological features of L. acuta. Studies made on the duration/survival of L. acuta on eleven common rice land weeds found in paddy fields showed that the bugscould complete their life cycle only on Echinoedria colonum and E. crusgalli. The bugs survived for short periods on a few of the otherweed hosts.ArticleItem Open Access Field evaluation of insecticides on the control of rice bug (Leptocorisa Acuta Thunb.) in epidemic outbreaks(Kerala Agricultural University, 1995) Krishnakumar, K; Visalakshi, A; KAUTwo field experiments were conducted to assess the efficacy of different insecticides for controlling Leplocorisa acula Thunb. at different population levels. In the first experiment, where there was more of a population stress, the insecticides malathion, methyl parathion and fenthion were found to he more effective in controlling the hug, the percentage reduction heing 75.72 to 97.15, 72.71 to 94.76 and 69.92 to 91.85 per cent respectively. In the second experiment with lesser population stress also, the same insecticides showed the maximum effect in control! ing Leplocorisa acula in the field. The effect of these insecticides was indicated by the higher grain/chaff ratio in all these treatments.ArticleItem Open Access Insecticidal dusts to control pests of stored paddy(Kerala Agricultural University, Vellanikara, 1968) Mammen, K V; Visalakshi, A; Nair, M R G K; KAUArticleItem Open Access On the effect of application of some pesticides on grain setting in rice(Kerala Agricultural University, 1976) Visalakshi, A; Rema Devi, L; Nair, M R G K; KAUArticleItem Open Access Optimum spray volume requirements for rice at different stages of growth(Kerala Agricultural University, 1984) Thomas Biju Mathew; Mohan Das, N; Visalakshi, A; KAUField experiments were conducted for two seasons in 1980-'81 at the College of Agriculture, Vellayani for assessing the optimum volumes of insecticide suspension required for treating rice crop at different growth stages of the crop using a pneumatic knapsack sprayer and mist blower. The results showed that the optimum volumesof 0.2",, carbaryl suspension required to give highest deposits on leaves were 200, 300, 500 and 500 I/ha in the case of a pneumatic knapsack sprayer and 90, 1 20, 1 80 and 1 80 I/ha in the case of a mist blower at 30, 45, 60 and 75 days after sowing respectively. The optimum volumes thus obtained were correlated with the leaf area indices of the respective stages of growth and relevant statistical models were fitted for both the type of sprayers.ThesisItem Open Access Organochlorine insecticide contamination in the inland ecosystems of Kerala(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1995) Rosalind, R S; KAU; Visalakshi, Aesidues of organochlorine insecticides in three different ecosystems Kerala viz., the fresh water ecosystems at Vellayani and Sasthamkotta and backwater region in lower Kuttanad were assessed. Residues in the three components of the ecosystem viz., water, sediment and fishes were estimated. Following were the salient findings. Among organochlorine insecticides (DDT, endosulfan, HCH widely uses) isomers of HCH alone were detected in the samples. The water in all the different regions were found polluted with varying levels of isomers of HCH. The content at different locations in each area did not show statistically significant variation, thus indicating a wide spreading of insecticide contaminants reaching the water boides. The pooled analysis of the data revealed that among the three ecosystems, water in Kuttanad was most polluted and it was followed by Sasthamkotta and Vellayani. The level of pollution is comparable with majority of levels reported from other parts of India so far. The levels of gamma isomer for which 3 ppb has been fixed as the Maximum Residue Limit for drinking purposes, did not reach hazardous levels. But the content of these toxicant in all situations exceeded the ‘safe criterion’ of 0.01 ppb fixed by EPA. Regarding the residues in sediments statistically significant variations did not exit among the locations at Vellayani and Sasthamkotta while at Kuttanad, Moncompu was more significantly polluted than Kumarakom and Pulinkunnu. In pooled analysis of the data Kuttanad and Vellayani were seen on par and more polluted than Sasthamkotta. Taking the residues in water and sediments together the three ecosystems could be ranked in the following descending order of pollution : Kuttanad, Vellayani and Sasthamkotta. Absence of beta and delta residues in water at Vellayani could be due to the settlements of the residues in sediments as shown by a higher proportion of these isomers in sediments at Vellayani than in other ecosystems. Several fold increase of the residue content in sediment compared to those of water revealed that the ‘sediments’ became a ‘sink’ for the pollutants in the ecosystem. Eteroplus suratensis, Heteropneustes fossilis and Macrobrachium rosenbergii (at Kuttanad) and M. idella idella (Vellayani and Sasthamkotta) contain residues of all isomers of HCH. In fresh water ecosystem E. suratensis had highest residue and it was followed by prawn and H. fossilis. In Kuttanad ecosystem H. fossilis was most contaminated and it was followed by M. rosenbergii. At Vellayani the fishes did not contain beta and delta isomers while the prawns contained all the four isomers. This indicated that the former absorbed the pollutant from water and the latter from water and sediments. Significant correlations were lacking between the residue content in fishes and the other components subjected to study in the environment. Residue levels in the animals chosen did not appear to reach hazardous levels. Predominance of beta isomer, known as a chronic toxicant and carcinogen, in the total residue content is alarming. The backwater and freshwater ecosystems in the state were seen polluted with isomers of HCH. Sustained and extensive monitoring of the residues and effective steps for reducing / eliminating the hazard are indicated.ThesisItem Open Access Persistence and metabolism of phorate in rice plants and in different soil types of Kerala and its effect on non target organisms(Division of Agricultural Entomology, College of Agriculture, Vellayani, 1987) Naseema Beevi, S; KAU; Visalakshi, AThe uptake, persistence and metabolism of phorate in rice plants and in different types of soil, viz., alluvial, sandy and lateritic loam when applied at 3 doses and 3 growth stages of the crop were studied by conducting field experiments. In these studies, the insecticides was applied as granules at 3 doses of 1.0, 1.25 and 1.5 kg ai/ha at 20, 40 and 60 days after planting. The residues were estimated colorimetrically and by bioassay. The metabolites in plants and soil were separated by T.L.C and further estimated colorimetrically at intervals of 2,7 and 14 days after application. The ultimate residues of the insecticide in grain and straw also were determined.ArticleItem Open Access Persistence of residues of phorate in rice grain and straw when applied at different growth stages of the plant(Kerala Agricultural University, 1992) Naseema Beevi, S; Visalakshi, A; KAUStudies on the persistence of phorate in the rice grain and straw when applied at different intervals after planting in different soil types of Kerala showed that no detectable residues persist in grains or straw at harvest when the crop was treated at 20 days after planting. Detectable residues were present in grains and straw at the higher two doses of 1.25 and 1.50 kg ai/ha applied at 40 days after planting and at all the doses of 1.0, 1.25 and 1.50 kg ai/ha applied at 60 days after planting and these residues exceeded the tolerance limit also.ThesisItem Open Access Residue problems in the control of insect pests in processed food commodities using aluminium phosphide(Department of Agricultural Entomology, College of Agriculture, Vellayani, 1984) Rema Devi, K; KAU; Visalakshi, AInvestigations were carried out to determine the bio-efficacy of fumigation with aluminium phosphide in controlling different species of insects feeding on stored wheat flour, maida, rice flour, rice, semolina, noodles, cattle feed, gram flour, soy beans, green gram, dhal, coffee, tea, cocoa powder, garlic, pepper and cumin under laboratory conditions at the doses 1.5, 3.0 and 4.5 g/m3 with an exposure period of 3 days. Studies revealed that the dose of 3.0 g/m3 was suitable for effective control of the pests and that the toxicity of the fumigant depended upon the media in which the insects were reared. Studies conducted on the relative susceptibility of different stages of insects feeding on different food commodities at the 3 doses revealed that adult stage was highly susceptible showing cent per cent mortality evenat the lowest dose of 1.5 g/m^. The egg stage of all the species in all the commodities was relatively resistant to the fumigant followed by pupae, larvae and adults in that descending order. The dose required for the elimination of the different life stages of different insects in different commodities varied depending upon the stage.Thus the percentage control of T. castaneum infesting seven food commodities varied from 92.49 to 100.00 per cent the percentage mortality of the egg ranged from 78*29 to 99.29* of larvae from 97*59 to 100.00 and of pupae from 93.29 to 100.00 per cent at the lowest dose of 1.5 g/m^,S. orvsae also, in three different products showed the same response where the percentage control varied from 93*09 to 97.00. In egg stage the variation in mortality was from 73.55 to 74.81 per cent, in larvae 85.06 to 86.98 per cent and in pupae the variation was from 76.00 to 78.05 per cent at the dose of 1.5 g/m . Similar results were obtained for A. fasoiculatus in three products, C. chinensis on pulses, C. cephalonica on rice flour and L. serricome on cumin.ThesisItem Open Access Studies on movement and placement of systematic granular insecticides in soil in relation to control of pests of pulses(Division of Agricultural Entomology, College of Agriculture, Vellayani, 1981) Nanda Kumar, C; KAU; Visalakshi, AThe horizontal movement of three systemic granular insecticides phorate, carbofuran and disulfoton in four different types of soils of Kerala viz. sandy, alluvial, red and laterite, was studied by observing the mortality of aphids released on cowpea plants at different distances from point of application of the granules . The effect of age of cowpea plants on the uptake of phorate was assessed by growing plants of different ages. Vertical movement of phorate and disulfoton in red soil was assessed in terms of residue levels after broadcast and point application by colorimetric and bioassay methods. The effect of placements of the systemic granules on pest infestation of cowpea was observed in a field experiment laid out in RBD and the incidence of leaf miner , aphids, flea beetle, leaf webber and pod borer was assessed . The effect of different placements of insecticides in soil on their persistance in cowpea was assessed by observing the mortality of aphids confined on the treated plants at ten-day intervals after application of the insecticides . The effect of placement of insecticide granules on plant growth characters viz. plant height, number of branches, weight of shoot, weight of root , length of tap root, number of nodules, dry weight of nodules and yield was assessed. Residues were estimated in the green pods forty-five days after application of the systematic granules.