PhD Thesis

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1989 - 198922010 - 20141

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    Incidence of Bacterial and Viral Diseases of Silkworm, Bombyx Mori L. in Bangladesh and their Control
    (University of Rajshahi, 1989) Barman, Anil Chandra; Rahman, Mustafizur; Quayum, M. A.
    Like other forms of life, the silkworm, Bombyx mori L. is also affected by various types of diseases. During the growth the silkworms come in contact with a number of pathogenic agents like virus, bacteria, fungus, protozoans etc. under natural environmental conditions. Life functions are thus interfered and a disease occurs. The ultimate result is the loss of worms and hence loss of cocoon production. The earliest scientific report on insect diseases was on silkworm ailments (Kirby 1826). Afterwards it was experimentally demonstrated that the micro­organisms are the causative agents for certain sickness in silkworms (Steinhaus 1963). A major breakthrough in our understanding of silk­worm disease was achieved by Pasteur (1885) who identified that the protozoan, Nosema sp. was responsible for the devastating disease ' pebrine' of silkworm (Rene Dubas 1960). Bacterial and viral diseases of silkworm are the most common diseases inhabiting all the silk producing countries and areas, although their severity varies with the consequent interaction of existing environment of different regions. Total crop losses due to these diseases are rarely known, but the cocoon yield is largely hampered affecting national plan as well as personal income. In any of the cases of bacterial or viral diseases, starting point is the individual silkworm from which the disease is spread to the population. The occurrence of disease in a population is the consequence of interaction between pathogen, host and the environment……………………….
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    Incidence of Bacterial and Viral diseases of silkworm. Bombyx mort l. In Bangladesh and their control
    (University of Rajshahi, 1989) Barman, Anil Chandra; Rahman, Musta­fizur
    Like other forms of life, the silkworm, Bombyx rnori L. is also affected by various t􀀪s of diseases. During the growth the silkworms come in contact with a number of pathcqenic agents like virus, bacteria, fungus, protozoans etc. under natural environmental conditions. Life functions are thus interfered and a disease occurs. The ultimate result is the forms and hence loss of cocoon production-. The earliest scientific report on insect diseases was on silkworm ailments ( Kirby 1826). Afterwards it was experimentally demonstrated that the micro- .__ organisms are the causative agents for certain sickness in silkworms (Steinhaus 1963). A major breackthrough in our unde􀁤standing of silk­worm disease was achieved by Pasteur (1885) who identified that the protozoan, Nosema sp. was responsible for the devastating disease ' pebrine' of silkworm (Rene Dubas 1960). Bacterial and viral diseases of silkworm are the most comnon diseases inhabiting all the silk prooucing countries and areas, although their severity varies with the ccnsequent interaction of existing env􀂅- ronment of different regions. Total crop losses due to these diseases are rarely known, but the cocoon yield is l;:irgely hampered affecting national plan as well as personal income. In any of the cases of bacterial or viral diseases, starting point is the individual silkworm from which the disease is spread to the pop..ilation. The occur1ence of disease in a p-,pulation is the con­ r---. since of interaction between pathcqen, host and the environment. -----------
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    Effect of Plant Extracts on the Growth and Development of the Mulberry Silkworm Bombyx Mori L
    (University of Rajshahi, 2014) Banu, Hosna Ara; Rahman, Sowdagar Mahfuzar; Ahsan, Md. Kamrul
    An attempt was initiated for the utilization of different plant materials as food supplement for the improvement of different economic traits of Bombyx mori L. For this purpose initially an experiment was conducted to screen out different parts of Abroma Augusta, Centella asiatica, Neolamarckia cadamba, Solanum tuberosum, Persicaria acuminata and Andrographis paniculate plant with respect to their toxic effect on silkworm, Bombyx mori L. Relative toxicity by probity analysis for different parts of six plants extracts at different feeding schedules against silkworm larvae have been found out. Results on the mean mortality percentage of the larvae indicated that all the parts of P. acuminata and A. paniculata extracts showed toxic effect. With the increase of the dose of the extracts of the plant materials mortality of the larvae were increased. The LD50 values for different parts extracts at different feeding schedules also implied that different parts of those plant extracts produced higher mortality so that fruitful results could not be achieved with the supplementation in the feeding of silkworm larvae. On the other hand, results on the mean mortality percentage of the larvae indicated that all the parts of A. Augusta, C. asiatica, N. cadamba, S. tuberosum plant extracts were not toxic. The LD50 values also reported the same effect. After screening, the effects of the supplementation of different parts, viz. leaf, stem, root extracts of A. Augusta, C. asiatica, N. cadamba, S. tuberosum on growth and development of B. mori at different feeding schedules, viz. fed only in 1st feeding of 3rd to 5th instar larvae (FS-1), fed every day in 1st feeding of 3rd to 5th instar larvae (FS-2), fed every day in 1st and 3rd feeding of 3rd to 5th instar larvae (FS-3) were conducted. Leaf extract of A. Augusta increased the WML, LML, BML at different doses compare to control while fed in FS-1, FS-2 and FS-3. The highest and the lowest results for these parameters were observed at 500 ppm and control respectively………………………………