Pebrine monitoring methods in sericulture

Abstract

Silkworm Bombyx mori , a monophagous lepidopteran insect is of great economic importance for the production of the natural fibre, silk. It is vulnerable to a diverse array of microorganisms resulting in crop losses to the farming fraternity practicing sericulture. Nosema bombycis Naegeli, a spore forming obligate intracellular microsporidia causes the devastating pebrine disease in silkworm. N. bombycis is transmitted via horizontal and vertical or transovarial transmissions. Pebrine inflicted extensive damage to the sericultural industry in Europe and Asia during the mid-nineteenth century; and still remains one of the impending challenges for the progress of sericulture across the world. The curative approaches for control of pebrine are often met with limited success and pebrine is the only disease which is being quarantined. The early detection or prevention of N. bombycis infection is an indispensable tool to control the spread of disease for stringent monitoring in the production of silkworm eggs (dfls: disease free layings; in an effect pebrine-free layings). The mother moth examination method employing light microscopy is widely used to diagnose/detect N. bombycis infection in seed multiplication farms and commercial seed production centres. Pebrine monitoring in different stages of the silkworm life cycle is of paramount importance for the sustenance of sericulture and is an integral part of silkworm disease management. This chapter summarizes the standard protocols employed for processing different samples (silkworm eggs, larvae, pupae, moth, faecal matter and dust) including sampling methods for observing pebrine spores as a part of systematic pebrine monitoring in the sericulture industry.