A new molecule reduces the cocoon production loss in the BmNPV infected Bombyx mori larvae rearing

Abstract

Bombyx mori nucleopolyhedrovirus, BmNPV, is the pathogen that causes mortality by the grasserie disease in larval Bombyx mori (Lepidoptera:Bombycidae). A molecule named Bm5 was reported as an inhibitor candidate of viral cathepsin (v-cath), which may protect B. mori from this disease. This study evaluated the efficacy of Bm5 in reducing sericultural loss due to BmNPV. The assays were carried out using B. mori fifth-instar hybrids that were inoculated with BmNPV and treated with Bm5. We recorded biological and productive variables to verify the effectiveness of the Bm5 treatment. Data on biological and economic parameters showed that the larval survival rate of the BmNPV-infected and Bm5-treated groups was 35.6% higher than that of the untreated BmNPV group. In addition, the pupae from the Bm5 treatment group survived and produced good-quality cocoons. The results of esterase dosage from the midgut and fat body showed that no change was detected in isoenzyme expression in BmNPV-infected larvae, regardless of Bm5 treatment. In conclusion, the Bm5 molecule may be used as a curative treatment to reduce the loss in silk production when B. mori larvae are infected by BmNPV.