Question

Pebrine disease of silkworms is caused by

• A. Nosema
• B. Plasmodium
• C. Dugesia
• D. Monocystis

Answer 1

The correct option is A

Nosema

The correct option is A.
Explanation of the correct option:

1. Pebrine disease is a paper-like black spot on the infected silkworm.
2. it is caused by Nosema bombycis or ricini.
3. In this, all tissues of the body of the embryo, larva, pupa, and adult moths are infected.
4. Symptoms like black spots, irregular exhatching of eggs, irregular sizes of larva, loss of appetite, and inactiveness are very common in silkworms.

Explanation of the incorrect options:
Option B:

Plasmodium is a causative agent of malaria.
Option C:

Dugesia is found on leaves, logs, and debris. They are flatworms.
Option D:

Monocytes are parasitic protozoans that cause diseases in earthworms.

Final answer: Pebrine disease of silkworms is caused by Nosema.