2. Institutional Publications
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Item Resistance of tapioca varieties to the red spider mite Tetranychus telarius Linn.(Kerala Agricultural University, 1974) Saradamma, K; Das, N MItem Effect of rice varieties on the extent of leaf consumption by caterpillars of Cnaphalorocis medinalis(Kerala Agricultural University, 1974) Das, N M; Nair, M R G KItem Relative contact toxicity of insecticides to the caterpillars of Cnaphalocroos Medinalis Guenee(Kerala Agricultural University, 1974) Das, N M; Nair, M R G KItem Relative field susceptibility of rice varieties to infestation by the rice leaf roller Cnaphalocrocis medinalis Guenee(Kerala Agricultural University, 1974) Das, N M; Nair, M R G KEighteen varieties of paddy were screened for their relative susceptibility to infestation by Cnaphalocrocismedinalis The cviposition response of the different varieties varied significantly. The varieties could be ranked in the following ascending order with reference to the extent of preference: Kochuvithu, TKM6, TKM1, Adt27, Ptb9, Pankaj, Triveni, 1' 1. Cavery, IR20, Aswathi, Karuna, Jagannath, Annapoorna, Rohini, Mashoori Jaya and iRH- Based on the extent of leaf damage caused by the larvae, Kochuvithu ranked as the least susceptible variety followed by TKM6, TKM1, Ptb9, Adt 27, Pankaj, Triveni, IR20, H4 Cavery, Aswathi, Karuna, Annapoorna and Jagannath there being no significant difference among themselves. IR8, Jaya, Rohini and Mashoori were most susceptible. Based on the extent of leaf damage caused by the larvae Kochuvithu ranked as the least susceptible variety followed by TKM6, TKM1, Ptb9, Adt 27, Pankaj, Triveni. IR20, H4, Cavery, Aswathi, Karuna, Annapoorna and Jagannath, there be ing no significant difference among themselves. Susceptibility of the riee varieties to damage by leaf roller in the field was positively correlated with the number of eggs laid on them.Item Persistence of some systemic insecticides in cowpea when applied as granules in different soil types of Kerala(Kerala Agricultural University, 1975) Das, N M; Dale, D; Sasidharan Pillai, KA pot trial was conducted to study the persistent toxicity of phorate, car. bofuran, mephosfolan and disulfoton to the pea aphid, Aphis craccivota on cowpea grown in sandy, laterite, red, forest and black soils treated with the above insecticides as granule. The persistent toxicity was highest in plants treated with disulfoton in all types of soils. Mephosfolan was next best in sandy, red and forest soils whereas carbofuran was next to disulfoton in laterite and black soils. The yields obtained from treated plants were significantly higher than those of corresponding controls. But there was no direct correlation between the persistent toxicity of insecticides and the yield. The yield factor appears to be influenced by the impact of the insecticide on some soil factors favouring plant growth.Item Field and laboratory evaluation of insecticide sprays against the rice leaf-roller Cnaphalocroos Medinalis guenee(Kerala Agricultural University, 1976) Das, N M; Nair, M R G KTwenty four insecticides were evaluated against the caterpillars of Cnaphalocrocis medinalis Guenee in the laboratory using a new laboratory technique of spraying them within leaf folds under a Potter's Tower and in field experiment in which the per cent reduction of larval population caused by spraying was assessed. The results of the two experiments showed strict correspondence. Ethyl parathion, carbaryl, carbophenothion, dimethoate, fenthion fenitrothion and leptophos were found very effective against C. medinalis larvae while phosphamidon, phorate, formothion, methyl demeton, quinalphos, monocrotophos, thiometon and acephate, were moderately effective.Item Effect of water level in rice fields on the population build up of the brown plant hopper, Nilaparvata lugens and on the incidence of hopper burn(Kerala Agricultural University, 1977) Das, N M; Thomas, M JItem Control of the insect pests affecting cowpea Vigna Sinensis(Kerala Agricultural University, 1977) Das, N M; Susamma Mathai; Christudas, S PIn a field experiment conducted in the red soil of Agricultural College Farm, Vellayani applying thimet, disulfotan, rnephosfolan and carbofuron granules at three different levels, applied at the' time of sowing, disulfoton at 1 kgai/ha was found an effective and economic method for controlling pea aphid upto 5 weeks after sowing. In another field experiment it was observed that spraying of different insecticides commencing from the time of flowering along with one application of disulfotan granules at the rate of 1 kg ai/ha at the time of sowing reduced the incidence of pea aphid and pod borers and increased the yield significantly. On a benefit cost ratio basis the effective insecticides could be ranked as follows: f enithion >f enitrothion > monocrotophos > carbaryl > phosalone > quinalphos.Item Effect of weathering on persistence of insecticide residues on glass surfaces(Kerala Agricultural University, 1981) George Koshy; Das, N M; Nair, M R G KItem Relative toxicity of some of the newer insecticides to adults of Euscyrtus Concinnus haan (Eneopteridae:Orthoptera)(Kerala Agricultural University, 1981) Baby P Skariah; Das, N M
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