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19823
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Subject: Entomology × End date: 1982 × Start date: 1982 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Use of synthetic pyrethroides for the control of pests of bitter gourd (Momordica charantia L) and snake gourd (Trichosanthes anguina L)
    (Department of Entomology, College of Agriculture, Vellayani, 1982) Kosaraju Ravindra, Nath; KAU; Sasidharan Pillai, K
    In a field experiment conducted at the Instructional Farm, College of Agriculture, Vellayani, during the summer season in 1982, the efficacy of four synthetic pyrethroids viz. permethrin, fenvalerate, cypermethrin and deltamethrin, on the pests of bitter gourd and snake gourd in comparision with the standard, malathion, was evaluated. Both the crops were sprayed thrice on need basis for controlling the various pests which infested the crops at different growth stages. Spotted beetle observed on bitter gourd at the time of first spraying was controlled by all the synthetic pyrethroids along with the standard for a period of 23 days after spraying. Fruit fly of the bitter gourd also was controlled by all the three sprayings and all the insecticides were effective in most occasions. Cypermethrin at higher dose was superior to the standard during the first spraying followed by fenvalerate and deltamethrin. In the second spraying deltamethrin was not so effective whereas permethrin was found more effective. Again in the third spraying deltamethrin and fenvalerate were more effective . The fruit fly damage observed for the entire crop season revealed the superiority of fenvalerate, permethrin and deltamethrin at their higher doses over the standard. Jassid on bitter gourd was controlled by all the insecticides except permethrin and cypermethrin at their lower dose for a period of 2 days after the spraying . But aphid could be controlled only with permethrin and fenvalerate at their higher dose along with the standard malathion for a period of 2 DAS. The fruit set and the flowering pattern were not affected by any of these insecticides.
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    ThesisItemOpen Access
    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; KAU; 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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    ThesisItemOpen Access
    Determination of phytotonic effect of insecticides on rice crop
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1982) Gade Krishna, Kumari; KAU; Mohan Das, N
    The phytotonic effect of tho commercial formulations of four insecticides viz. carbofuran, phorate, monocrotophos and quinalphos at different growth stages of rice was i assessed through field experiments The role of adjuvants in the formulations in causing tho phytotonic effect was studied in pot culture studies. 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.