ABSTRACT This study was carried out to investigate the influence of petroleum-ether extracts of mulberry leaves (Morus alba), basil leaves (Ocimum basilicum), and black seed (Nigella sativa) as disinfectants on some biological and physiological aspects of the mulberry silkworm, Bombyx mori L. larvae artificially infected with Bacillus thuringiensis and Beauveria bassiana. The results showed that silkworm larvae artificially infected with B. thuringiensis using black seed and mulberry leaves extracts (2, 3%) produced the highest cocooning percentage (98%) while using (3%) basil leaves extract enhanced female fecundity (634 egg/female). Also, the highest total soluble protein in hemolymph recorded 8.5 mg/ml when using 1% of Black seed and Basil leaves extracts with infected larvae with B. thuringiensis. Otherwise, silkworm larvae artificially infected with B. bassiana using black seed extract 3% led to the highest cocooning percentage (98%) and maximum egg number deposited (613 egg/female). In addition, all plant extracts under study increased the activity of transaminase enzymes. Moreover, concentrations of basil leaves extract increased the total protein in haemolymph of infected larvae with B. bassiana. Key words: Bombyx mori, Bacillus thuringiensis, Beauveria bassiana, mulberry leaves, basil leaves, black seed.