TRICHOGRAMMA PART 1

Summary

This video guides viewers through the process of propagating *Trichogramma* parasitoids using an alternative host, *Corcyra cephalonica* larvae. The process includes sterilizing and preparing a special feed mixture, breeding *Corcyra*, harvesting eggs, and sterilizing them using ultraviolet radiation. The eggs are then used as hosts for *Trichogramma* development. The video provides detailed steps for each phase, ensuring successful breeding and storage of *Corcyra* eggs for *Trichogramma* propagation. This method aids in the development of a sustainable biological control agent for agricultural pests.

Takeaways

• 😀 Trichogramma is a parasitoid used for controlling rice stem borer pests, and its propagation can be done in the laboratory using alternative hosts.
• 😀 The primary alternative host for propagating Trichogramma is the rice moth larvae, *Corcyra cephalonica*.
• 😀 To begin the propagation, a suitable feeding medium needs to be prepared, consisting of ground corn and poultry feed, which must be sterilized by roasting for 20 minutes.
• 😀 The cornmeal is roasted for 15 minutes before adding the poultry feed, and then the mixture is cooled before being placed into starter containers.
• 😀 Initial starter *Corcyra cephalonica* larvae can be sourced from rice milling warehouses where the larvae or moths are present.
• 😀 The correct ratio for breeding *Corcyra* involves one male to three females, which are kept in starter containers for 2-3 weeks until they reach the third instar larval stage.
• 😀 After reaching the third instar, the larvae are moved to dry containers where they are kept for around three weeks until the adult moths emerge.
• 😀 Moths are harvested from dry containers and placed into egg-laying tubes, where they lay their eggs on a substrate.
• 😀 The egg-laying tubes should be placed in a dim room at room temperature, and a bed or substrate should be added to encourage egg-laying.
• 😀 After 24 hours, the eggs can be harvested by gently scraping them off the surface of the egg-laying tube. The eggs are then cleaned, sterilized using ultraviolet radiation, and prepared for further use in the *Trichogramma* propagation process.

Q & A

What is Trichogramma, and how is it related to the production of parasitoids?

Trichogramma is a parasitoid that targets the eggs of rice stem borers. It is used in biological pest control and can be bred in laboratories using alternative hosts like Corcyra cephalonica.

Why is Corcyra cephalonica used as an alternative host for Trichogramma?

Corcyra cephalonica, or rice weevil, is used as an alternative host for Trichogramma because it can be easily bred in controlled environments, providing a consistent source of eggs for Trichogramma to parasitize.

What is the first step in preparing the alternative host for breeding Trichogramma?

The first step is to prepare the food medium for Corcyra cephalonica, which consists of ground cornmeal and poultry feed. This mixture must be sterilized by roasting for 20 minutes.

How do you sterilize the food medium for the alternative host?

The food medium is sterilized by roasting the ground cornmeal and poultry feed for 15 minutes, and then adding the poultry feed and roasting for an additional 5 minutes. This ensures the medium is free from contaminants.

What is the importance of the sterilization process in breeding Corcyra cephalonica?

Sterilization is essential to prevent any unwanted microorganisms or pests from interfering with the breeding process and to ensure a healthy environment for the larvae of Corcyra cephalonica.

How long does it take for Corcyra cephalonica larvae to reach the third instar stage?

It takes about 2 to 3 weeks for Corcyra cephalonica larvae to develop into the third instar stage after being placed in the starter container.

What is the next step after the larvae of Corcyra cephalonica reach the third instar stage?

Once the larvae reach the third instar stage, they are transferred to dry containers where they are kept for about 3 weeks until they mature into moths.

How are the eggs of Corcyra cephalonica collected for use as an alternative host?

The moths from the dry containers are harvested and placed into egg-laying tubes. The eggs are collected after 24 hours when they are ready to be harvested.

What is the purpose of sterilizing the Corcyra cephalonica eggs?

The eggs are sterilized using ultraviolet (UV) light for 20 minutes to eliminate any potential pathogens or contaminants, ensuring the eggs are safe for use in breeding Trichogramma.

How are the sterilized Corcyra cephalonica eggs prepared for storage?

The sterilized eggs are spread evenly on a petridish and then placed onto bias paper, which is coated with Arabic gum and labeled with the date of collection and expiry. The eggs can be stored in a refrigerator for up to 14 days.

What is the role of the bias paper in the process of handling Corcyra cephalonica eggs?

The bias paper, coated with Arabic gum, serves as a medium to hold the sterilized eggs in place and ensures that they are properly labeled for identification and future use.