The main silkworm diseases are pebrine, flaccidity, calcino and yellowness.
Pebrine is contagious and hereditary and can affect the silkworm at any time in its life, even before birth. The larva stops eating, does not grow, becomes weak until it dies. The disease is recognizable on the silkworm's body, which initially fills with yellow and brown spots and then black. In 1860, a serious epidemic of pebrine occurred in Ticino, which seriously compromised silkworm breeding.
Flaccidity occurs especially when the silkworm molts in its larval stage and it is therefore weaker. The larva does not eat and does not move and its body swells, turning a pinkish color.
Calcino kills the silkworm in about a day, making it stop eating and moving and giving it a pinkish color. The silkworm's body loses elasticity until it becomes paralyzed, resembling a piece of lime, and eventually dies.
The yellowness makes the silkworm turn yellow. The larva swells so much that its legs retract and the silkworm, slowed down, stops eating and dies. A thick yellow-white liquid replaces the blood.