The pebrine disease of silk worm is caused by

The pebrine disease of the silkworm is caused by Protozoa.
The pebrine disease is locally known as phootuka “Saiutha” (spotted) in Assamese and is caused by the protozoan parasite Nosema bombycis (Nosema sp.) of the family Nosematidae.
Nosema parasite invades all the tissues of the body of the embryo, larva, pupa and moth.