Antibacterial activity of six different species of fungal extracts viz., Aspergillus ochraceous, Paecilomyces variotii, Schizophyllum sp., Epicoccum sp., Metarhizium sp., Aspergillus niger were evaluated against ten serotypes of Bacillus thuringiensis to develop new bioactive secondary metabolites from the microbial sources. Fungal crude extracts were isolated by ethyl acetate solvent extraction method and product yields varied from to . Thin Layer Chromatography was carried out for detecting the small molecule compounds present in the crude extracts. | Effect of fungal extracts on bacillus thuringiensis serotypes causing flacherie disease in mulberry silkworm, Bombyx mori L.