Stifling treatments are applied to silk cocoons in order to kill the pupae, preventing the emergence of moths and allowing to preserve the silk during long periods of time. All of them involve the application of aggressive steps, such as sun exposure, hot steam from boiling water or hot air, during hours or even days.

Why are cocoons stifled answer?

The cocoons have to be stifled to kill the larvae inside as otherwise; it will cut its way out after growing into a moth and spoil the cocoon. ... Hence the pupae are killed without damaging the cocoon. Complete step by step answer: 1) Rearing silk worms for the production of silk is named as sericulture.

Why are cocoons stifled for 7th class?

The cocoons have to be stifled to kill the larva. It cocoon isn't stifled the larvae inside them won't die and later into a moth and fly away. Therefore we can't get thread of silk from such a quality fibre for fabric. Stiffing also helps to store the cocoons for a long time.