Browsing by Author "Mohan Das, N"

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    Biological activity of different plant extracts with particular reference to their insecticidal,hormonal and antifee ding actions
    (Department of Entomology, College of Agriculture, Vellayani, 1989) Saradamma, K; Mohan Das, N
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    Determination of phytotonic effect of insecticides on rice crop
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1982) Gade Krishna Kumari; Mohan Das, N
    When applied at 15 DAS alone carbofuran at 0.5 kg ai/ha, phorate 1.25 kg ai/ha and monocrotophos and quinalphes at 0.25 kg ai/ha increased the yield significantly over control.Monocrotophos and quinalphes at 2 kg ai/ha wore found phytotoxic The higher doses of 4 kg ai/ha of carbofuran c and 10 kg al/ha of phorate were on par with the lower doses of the insecticides. This revealed the lower. dose were the maximum levels to which the plants in nursery could respond to the toxicants.
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    Differentiation of beef from chevon by serological methods
    (Department of Veterinary Public Health, College of Veterinary and Animal Sciences, Mannuthy, 1980) Mohan Das, N; Prabhakaran, P
    Identification of meat of different species by physical examination alone is difficult. Serological tests are advocated as one of the reliable methods. In order to differentiate beef from chevon, tube precipitation and gel-diffusion tests were concurrently done. Antisera raised in rabbits against beef and chevon, and saline extracts of meat samples collected from known sources as antigen, were used for the tests. In order to remove cross-reacting antibodies, the sera were absorbed with freese – dried antigen against which cross- reacting antibodies were present. Tube precipitation and gel-diffusion tests were adopted for identifying the meat samples. The tests conducted on eighty samples of meat gave cent percent accuracy in identifying the meat. Buffalo meat and mutton used in the test as antigen reacted in the same manner as that by beef and chevon respectively. It was also possible to detect the presence of adulterant in a mixed sample of beef and chevon when the proportion or level of adulterant was up to 20 percent. The antisera could be preserved for more than six months at 50C and-200C without loss of efficacy inspite of occasional electricity failure. It is concluded that tube precipitation and gel-diffusion tests are reliable methods for differentiation of beef and chevon.
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    Distribution of spindle bug of Arecanut carvaholia arecae Miller and China in Kerala: its broecology, suspected role as the vector of yellow leaf disease and control
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1990) Stanley Jacob, A; Mohan Das, N
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    Effect of synthetic pyrethroids on the pests of paddy
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1982) Balaji, T S B; Mohan Das, N
    The relative efficacy of four synthetic pyrethroide against the important rice pests was assessed through a field experiment laid out at the Model Agronomic Research Station karamana, during 1981, taking carbaryl as standard. Against the rice gall midge Pachydiplosis oryzae cypermethrin (50 and 25 g ai/ha) and permethrin (50 g ai/ha) were found superior, The low variation in tho percentage incidence of silver shoots in plots treated with pyrothroids and carbaryl showed that the use of the former category of pesticides is not justified due to the high, cost involved.
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    Effect of varying volumes of pesticide spray fluid on the control of rice pests
    (Department of Entomology, College of Agriculture, Vellayani, 1987) Viswanathan, G; Mohan Das, N
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    Insecticide deposits and residues on paddy with reference to volume of spray fluid applied at different growth stages of the crop
    (Department of Entomology, College of Agriculture, Vellayani, 1982) Thomas Biju Mathew; Mohan Das, N
    A set of experiments were conducted for assessing the optimum volumes of carbaryl suspension required to spray rice at different growth stages of the crop, using a pneumatic knapsack sprayer and a mist blower. The levels of pesticide deposit formed by spraying the crop at varying levels of pesticide suspension were taken as the indices of bio efficacy and these were also correlated with the leaf area indices of the crop at different growth stages . The level of contamination of the rice eco-system was assessed in terms of pesticide residue in irrigation water of the treated plots. A correlation between different levels of pesticide deposits caused by varying the volumes of the spray fluid was assessed by trials conducted against leaf roller and case worm infesting rice. In the first experiment , the crop was sprayed with 100, 150, 200, 250, 300, 350, 400, 450, 500, 550 and 600 1/ha of 0.2% carbaryl suspension on using a pneumatic knapsack sprayer. Deposit on leaf and stalk of the plants, two hours after spraying , was estimated from the representative samples adopting the chemical assay method of Benson and Finocchiare (1965). The experiment was repeated at four different growth stages of the cropviz. 30, 45, 60 and 75 days after sowing. The results showed that the minimum levels of carbaryl suspension required to cause significantly higher levels of deposit on the leaves were 200, 300, 400 and 500 1/ha for the crop at 30, 45,60 and 75 days after sowing respectively.
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    Optimum spray volume requirements for rice at different stages of growth
    (Kerala Agricultural University, 1984) Thomas Biju Mathew; Mohan Das, N; Visalakshi, A
    Field 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.
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    Studies on the parasitic nematodes associated with vegetables in kerala
    (Division of entomology ,Agricultural college and research institute ,Vellayani., 1968) Ramakrishnan Nair, N; Mohan Das, N
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    Studies on the population of soil nematodes in relation to certain chemical and biotic factors of soil
    (Division of Entomology, Agricultural College and Research Institute, Vellayani, 1969) Ravindran Nair, K K; Mohan Das, N
    A total of 40 soil samples were collected and analysed to study the variations in the population of plant parasitic and non parasitic soil nematodes with reference to the chemical and biotic environments existing in soil. The total population of soil nematodes and the population of non-parasitic forms show a positive correlation with the pH of the soil within a range of 4.5-7.4. The parasite population is not correlated with the pH of the soil. There exists no correlation between the soil nematode population on the one hand and organic matter content , total soluble salts, and fungus and bacterial population of the soil on the other.