PREVALENCE OF SILKWORM DISEASES AND THEIR IMPACT ON COCOON PRODUCTIVITY IN THE SELECTED AREAS OF KARNATAKA, INDIA

摘要

Domestication of mulberry silkworm for thousands of years, made it susceptible to different diseases. Understanding the reasons for occurrence of silkworm diseases and the extent of crop loss due to diseases at farmers' conditions is essential in formulating silkworm disease management strategies. Periodic survey on silkworm diseases is imperative to find out the status of disease incidence in different sericultural areas. Hence, in the present study a survey was conducted for two years (October, 2012 to September, 2014) to find out the prevalence of silkworm diseases in the selected areas of Karnataka viz., Bangalore Rural, Kolar and Mandya and their impact on cocoon productivity and factors responsible for low cocoon yield (<60 kg/100 dfls of rearing). The average data on the point prevalence of diseases in two years indicated the prevalence of 3.37 % of total diseases in which grasserie was 1.03%, flacherie was 2.15%, muscardine was 0.19% and no incidence of pebrine throughout the period. Grasserie prevalence was more during summer (1.20%), and flacherie and muscardine were more during winter season. Among 720 farmers crops surveyed during the period, 625 farmers (86.81 %) were harvested >60 kg cocoons/100 dfls of rearing and 95 farmers (13.19%) were harvested <60 kg cocoons/100 dfls of rearing. The major reasons for harvesting <60 kg cocoons/100 dfls (less than potential of the hybrid) are poor quality leaf (6.81%), poor rearing management (2.36%).