The percentage of the number of Pr increased at 24, 36 and 48 h post-infection, 5.8, 7.6 and 6.6%, respectively. As shown in Figure 1a, b, c and d the infection of B. mori fifth larval instar with E.coli markedly increased the per-centage of the number of Pl and Gr at 48 h post-infection to about 16.7 and 35%, respectively.