Question

Which of the following agents affects hatching of silkworm eggs?
A. Protozoan parasites
B. Fungus
C. Mulberry leaf fermentation
D. Virus

Answer 1

Hint: When a female silk moth lays eggs, the life cycle of the silk moth begins. The caterpillars or larvae of the silk moth are hatched from the silk moth's eggs. Silkworms produce pupa by feeding on mulberry leaves. To keep itself alive during the pupa stage, the silkworm weaves a net around itself. After that, it swings its head, spinning a protein fibre that eventually turns into silk to build a cocoon.

Complete answer:
Let us see each of the options to find out the correct answer.
Option: A - Pebrine is a silkworm protozoan illness caused by microsporidian parasites, primarily Nosema bombycis. Nosema is a parasitic infection that kills all silkworms that hatch from contaminated eggs. It is transmitted by the food that silkworms eat. The microsporidium will be passed on to the eggs by the mother moth, and all worms emerging from contaminated eggs will perish in the larval stage.
Thus, Option A is correct.
Option: B – Fungal diseases in silkworms are commonly associated with their larval stages and are not transferred in the eggs.
Thus, Option B is not correct.
Option: C – Mulberry leaf fermentation has no links to the life cycle of silkworm which lays eggs only on fresh mulberry leaves.
Thus, Option C is also not correct.
Option: D – Viral diseases in the silkworm are found only in larval and adult stages. So, it does not affect the hatching of silkworm eggs.
Thus, Option D is also not correct.

Therefore, option A. Protozoan parasites is the correct answer

Note:
Pebrine, the most dangerous protozoan disease of silkworms, is called from the afflicted worms' pepper-like black patches. The major causative organism is Nosema bombycis. Due to poor glue deposition, infected eggs do not adhere firmly to the egg card. These pale yellow eggs have a poor chance of hatching. It is very common in the rainy and winter season.