Silkworm disease resistance management: Strategies, mechanisms and emerging approaches

Abstract:

Sericulture, the practice of growing silkworms (Bombyx mori L.) for silk production, is an important agro-based industry that supports the livelihoods of millions of farming families throughout Asia, mainly in India, China, Japan and Korea. Silkworms are susceptible to a variety of infections, including viruses, bacteria, fungus, protozoa and nematodes which is one of the most serious risks to sustainable silk production. These illnesses collectively cause yield losses of 15 to 40% of potential silk output each year. The current review summarizes current understanding about cause of silkworm diseases, host immunological responses and the range of management techniques available to sericulturalists and researchers. The principal disorders covered include nuclear polyhedrosis virus (BmNPV), cytoplasmic polyhedrosis virus (BmCPV), flacherie caused by bacterial infections and muscardine caused by entomopathogenic fungi, pebrine caused by the microsporidian Nosema bombycis, and grasserie as well as the immune mechanisms deployed by silkworms against these pathogens. Management approaches discussed span conventional sanitation practices, chemical and biological control measures, selective breeding for disease resistance, marker-assisted selection, transgenesis, RNA interference, and emerging nanotechnology-based strategies.