Question

Pebrine disease of silkworms is caused by
a. Nosema
b. Plasmodium
c. Dugesia
d. Monocystis

Answer 1

Hint: Pebrine disease is also called as pepper disease, the silkworm affected by pebrine has brown color spots and larva, and it is unable to spin the silk thread, and the parasite is transmitted from one generation to other generation by infected eggs.

Complete answer:
- Pebrine disease of the silkworm is caused by protozoan microsporidian parasites, mainly Nosema bombycis.
- The first person who identified this pebrine disease in the silkworm was Antoine Bechamp.
- This Nosema bombycis is a microsporidium, which mainly infects the larva, where the infected larva is covered by brown spots, where it is unable to spin the silk thread.
- This parasite mainly kills all silkworms, which are hatched from the infected eggs.
- This parasite attacks mainly through the food, which was eaten by the silkworm.
- If this microsporidium of the parasite, attacks the silkworm in the larval stage, it doesn’t show any symptoms that are visible.
- If the mother moth is infected, this parasite microsporidia enters the egg from the infected mother.
- The worms that hatch from the infected eggs, mostly die in the larval stage only.
- So if the infected hatch eggs, then the moth should be checked, by examining the moths’ body fluid.

Hence, the correct answer is option (A).

Note: The larva after infection, which means 3rd and 4th round should also be checked, because there is a chance secondary contamination, eggs should be injected with 2% formalin, for 5 minutes to kill the germs of the pebrine, and the disinfection of tools and rearing house should be cleaned with 2% formalin.