~ 2720 ~ Journal of Pharmacognosy and Phytochemistry 2018; 7(5): 2720-2724 E-ISSN: 2278-4136 P-ISSN: 2349-8234 JPP 2018; 7(5): 2720-2724 Received: 07-07-2018 Accepted: 09-08-2018 Shashidhar KR Scientist (Sericulture), ICAR- Krishi Vigyan Kendra, Tamaka, Kolar, Karnataka, India Thulasiram K ICAR- Krishi Vigyan Kendra, Tamaka, Kolar, Karnataka, India Noorulla Haveri ICAR- Krishi Vigyan Kendra, Tamaka, Kolar, Karnataka, India Correspondence Shashidhar KR Scientist (Sericulture), ICAR- Krishi Vigyan Kendra, Tamaka, Kolar, Karnataka, India Effectiveness of bed disinfectants on silkworm diseases and cocoon yield under tropical conditions of Kolar district, Karnataka Shashidhar KR, Thulasiram K and Noorulla Haveri Abstract The impact of bed disinfectants for successful cocoon harvest and crop stability was successfully demonstrated in the farmer’s field during 2014-15. The study revealed that, application of Ankush vijetha green and slaked lime powder combination (T3) bed disinfectant was recorded low incidence of silkworm diseases like grasserie (0.10 – 0.08 %), flacherie (0.25 – 0.15%) and muscardine (0.05 – 0.35%) and lower defective cocoon percentage viz., stained cocoons (0.10 – 0.10 %), flimsy cocoon (0.30 – 0.04%) and uzi pierced cocoon (0.80 - 0.30 %) during post rainy and rabi seasons respectively. Further, single cocoon weight (1.821 g), shell weight (0.340 g), pupal weight (1.456 g), shell percentage (18.75 %), filament length (851.13 mtrs) and cocoon yield (81.10 kg/100 dfls) were recorded high in T3 compared to application of bundh powder (T1). Keywords: Silkworm disease, defective cocoon, bed disinfectant, silkworm Introduction The mulberry silkworm Bombyx mori L. is one of the productive insects exploited for silk of commerce. The management of silkworm diseases is a vital component of successful silkworm rearing for obtaining higher cocoon yield and quality. The silkworms are more sensitive to environmental, nutritional and microbial factors, resulting in various diseases leading to silkworm mortality and cocoon crop loss all through the year. The most prevalent and serious diseases in the silkworm are grasserie, flacherie, muscardine and pebrine caused by virus, bacteria, fungi and microsporidia, respectively (Jiang and Xia, 2014) [9]. The diseases prevail throughout the year, and in tropics they are significantly high (Srivastava and Kumar, 2009) [12]. In India, the cocoon crop loss due to diseases was reported as 15-20 % (Balavenkatasubbaiah et al., 2011; Selvakumar et al., 2002) [3, 11] . Viral diseases account for almost 70 % of the total loss due to diseases (Babu et al., 2009) [2] . One of the major constraints in silk cocoon production is the diseases in silkworm rearing. Once the pathogen invades the silkworm, it is difficult to curb the pathogen. Hence, prevention of any disease is rather essential than attempting to control or cure. To curb the diseases in silkworm rearing, different bed disinfectants are evolved viz., Vijetha, hydrated lime, Bundh powder, active lime, Captan, Dithane M-45, RKO, Ankush, Vijetha Supplement, Resham jyothi, Labex and formalin chaff. Among these most commonly used bed disinfectants by the farmers are slaked lime, bundh powder, Vijetha which are being used in large quantities without any justification. Hence, the present study was carried out to find the suitable bed disinfectant to reduce the silkworm disease effectively for quality cocoon production at farmers fields. Materials and Methods The present study was carried out to know the effectiveness of bed disinfectants against diseases of silkworm during Post Rainy and Rabi season in 2014-15 at fifteen sericulture farmers in Hoohalli Village of Kolar District by ICAR-Krishi Vigyan Kendra, Kolar, Karnataka, India. For silkworm rearing, V-1 mulberry variety grown in red soil with spacing of 90 x 90 cm of the 5-10 years old plantations was used for the study. Before the commencement of silkworm rearing, the rearing room and appliances were thoroughly cleaned and the floor was washed using 5 per cent bleaching powder solution. Then the whole rearing house was disinfected with four per cent formalin at the rate of 1.5ml/ m2. Popular multi x bivoltine cross breed PMxCSR2 was used in all the experiments. Silkworm rearing was carried out in individual compartments assigned with following treatments