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1984 - 19874
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Subject: Entomology × Author: KAU × End date: 1987 × Start date: 1984 × Thesis Type: M.Sc ×
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    ThesisItemOpen 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, A
    The 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.
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    ThesisItemOpen Access
    Studies on insect pests and diseases of rice earhead and their control
    (Department of Entomology, College of Agriculture, Vellayani, 1987) Annie Thomas; KAU; Rajan Asari, P A
    A random sample survey on insect pests and diseases infesting rice during, flowering stage was conducted to collect information on the occurence of pests and diseases on rice earhead of different localities in Trivandrum district. Itcould be observed that L.acuta was the most important pest occurring throughout the area surveyed . The importance of rice bug was further proved by the mean number of insect present in different localities. The mean number of rice bug varied from 0.25 to 2.45 which showed the existence of considerable variation according to localities and varieties. The high yielding varieties invariably were seen more susceptible to the pest infestation than the local cultivars.
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    ThesisItemOpen 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, A
    Investigations 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.
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    ThesisItemOpen Access
    Use of organic amendments for the control of root-knot nematode In brlnjal
    (Department of Agricultural Entomology, College of Agriculture, Vellayani, 1986) Kamalakshi Amma, P L; KAU; Ravindran Nair, K K
    Two field experiments were conducted - one for evaluating oilcakes and another for evaluating organic wastes for the control of the root-knot nematode Meloldogyne incognita infesting brinjal, (These experiments were carried out in the Instructional Farm, College of Agriculture, Vellayani, in an area already infected by root-knot nematode. The experiments were laid out in randomised block design with three replications. In the first experiment there were ten treatments including the control and in the second experiment there were eleven.treatments including the control. Organic amendments were applied to the soil three weeks prior to planting and watering was done during this period for the proper, decomposition of these materials. Results were assessed in terms of yield, growth parameters, gall formation and population of nematode. Results indicated that the nematode population in roots as well as in soil was significantly reduced by the application of oilcakes and organic wastes. It was also observed that the intensity of gall formation on roots was considerably reduced as a result of application of organic amendments. Reduction in the population of the nematode and in the intensity of gall formation in turn resulted in bettor crop stand and increase in yield. (Different methods of application vis. application in the planting pit and broadcasting in the plot did not vary in efficacy.