The genus Enterococcus, a group of gram-positive bacteria, currently comprises 62 described species. In sericulture, some enterococci are serious pathogens causing the gastrointestinal disease “flacherie” in silkworm larvae reared on artificial diets. In the present study, the author evaluated the bactericidal efficacy of a new chlorine-based disinfectant cleaner for sericulture (DCS) consisting of NaOCl, 0.5% Na₂CO₃ and 0.2% Na₆P₄O₁₃. By varying the concentrations of free available chlorine (FAC) in the DCS from 256 to 1,024 mg/L, each bacterial suspension of four Enterococcus species (E. faecalis, E. faecium, E. hirae and E. mundtii) was tested with the DCS (20°C) under clean or low soiling conditions according to the European Norm 1656 method used for industrial purposes. The test results showed that the DCS with FAC 256 mg/L under the clean condition (0.03% BSA) disinfected all Enterococcus species in 1 min with a viable bacterial count log reduction value (VBC-LRV) of >6. In contrast, under the low soiling condition (0.3% BSA), more than FAC 768 mg/L was required in the DCS to disinfect all enterococci tested in 3 min to achieve a VBC-LRV of >5. In this study, E. faecalis was found to be susceptible to DCS. In contrast, E. hirae and E. mundtii were more tolerant to DCS than E. faecium. This result suggests that the susceptibility of Enterococcus to some disinfectants may differ between species and should be considered when evaluating the bactericidal efficacy of disinfectants against Enterococcus species in future research.

 In order to clarify the hereditary of the occurrence of fine fibers separated from the cocoon filaments, which are the main cause of the aggregation of white spots (lousiness) in silk fabric, we generated two silkworm lines using a fine fiber assembly (FFA) method. For genetic analysis, “Asa” (F7) and “Cevennes White” (CV) were used as a line with high FFA value and low FFA value, respectively. We succeeded in generating a line with higher FFA value by inbreeding of F7 while a line with lower FFA value was prepared by inbreeding of CV. The FFA values of F1 crosses between F7 and CV were extremely low, indicating that the gene involved in the oc- currence of the fibers may be recessive. Furthermore, the segregation ratios of BF₁ [(CV × F7) × F7] and F₂ [(CV × F7) × (CV × F7)] showed the presence of minor gene(s) as well as the recessive major gene in the occurrence of the fibers.