Studies on the management of flacherie in the mulberry silkworm bombyx mori l

Abstract

Sericulture is one of the most labour intensive sectors, combining activities of both agriculture and industry. It is practiced in about 53,814 villages all over the country. It provides employment to about six million people, most of them being small and marginal farmers, or tiny and household industry mainly in rural areas. Silk and silk goods are very good foreign exchange earners. The Indian silk goods have high export potential because of its distinctness and low production cost. During 2007-2008 the total silk exports were Rs. 1,376.91 crores.Mulberry silkworm Bombyx mori is a poikilotherm, susceptible to several diseases (Prasad, 1999). There is no silkworm race at present, which deemed as totally resistant to diseases or pests (Nagaraju, 2002). Bacterial diseases are common in silkworms and tend to occur in the hot and humid summer and autumn rearing seasons. The bacterial diseases are classified as bacterial septicemia, bactericemia and bacterial toxicosis. The haemolymph and silkglands are the major centres for high multiplication of bacteria. The damage to the gut wall paved way for the entry of the pathogens into the haemocoel. Bacterial flacherie is one of the serious diseases of silkworm causing cocoon crop loss to the tune of 75 per cent (Sidhu and Singh,1968). Various ecological factors such as higher and lower temperature, humidity, ventilation and feed adversely affect the physiological functions of silkworm. Stress produced by inadequate hygiene like contaminated rearing trays, sheet papers, cowdung and malnutrition are responsible for bacterial flacherie in B. mori. newline newline