Incidence of Bacterial and Viral diseases of silkworm. Bombyx mort l. In Bangladesh and their control

Abstract

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. -----------