In vitro testing of common disinfectants used in sericulture to control the growth of fungi in rearing houses

摘要

Silkworms are susceptible to a number of diseases. For controlling diseases, disinfection is the best prophylactic measure. Present study aims to identify the load of fungal pathogen present in the rearing rooms before and after disinfection also the in vitro testing of disinfectants (Sanitech, Asthra, bleaching solution, 2% formalin and 70% alcohol) against the fungus culture was studied. In disinfected floor, wall and washed materials like stand, tray in all the models studied, swab germ load as number of colonies were reduced to some extent but not completely removed. Quantification of Colony Forming Unit Area (CFUA) indicated that in all three models showed that all colonies in floor, wall, tray and newspaper were reduced significantly after disinfection. Seven different fungal colonies were isolated and cultured on potato dextrose agar media and identified according to colour, shape and margin out of these 5 isolated fungal colonies (Aspergillus tamarii, Aspergillus flavus, Aspergillus niger, Neurospora spp. and Beauveria bassiana) were tested against 5 disinfectants. Bleaching solution had highest effect (25.250 mm) in controlling Beauveria bassiana (muscardine causing agent to silkworm) and significantly more (p<0.05) than formalin (19.500 mm). Aspergilosis disease causing agent to silkworm Aspergillus tamarii was controlled by formalin significantly (p<0.01) with highest effective zone among all the disinfectants used. Aspergillus flavus was controlled by bleaching solution with highest clear zone (20.875 mm) and non significant with Asthra (16.00 mm) and formalin (15.500 mm). Hence in vitro testing proved 2% bleaching solution with 0.3% slaked lime was best in effectively controling the fungal diseases followed by 2% formalin solution.