Entomopathogenic fungi are valuable agents in integrated pest management (IPM) systems and are among the primary natural causes of mortality in rice pests. Unlike viruses and bacteria, parasitic fungi possess an active infection mechanism, providing significant advantages in locating, infecting, and attacking insect pests, particularly sap-sucking insects.

The application of biological control methods in agricultural fields helps reduce production costs and minimize the use of chemical pesticides. Biological pest management has been widely adopted in many countries, where farmers can produce and release beneficial natural enemies themselves. In Vietnam, numerous successful studies have demonstrated the effectiveness of biological control agents; however, this approach has not yet received adequate attention. Recently, the use of the green fungus Metarhizium anisopliae for controlling brown planthoppers has shown remarkable effectiveness while significantly reducing production costs.

The project entitled “Application of Green Fungus Production Technology at Farm Household Scale for Brown Planthopper Control in Rice Fields of the Mekong Delta” has been recognized by the Plant Protection Department as a new technical advancement and has been introduced into agricultural production.

This biological product offers outstanding advantages in controlling brown planthoppers, reducing environmental pollution, enhancing biodiversity in rice field ecosystems, and lowering production costs associated with chemical pesticide applications.

Therefore, the rapid production of green fungus bioproducts (Ometar) at the household level, enabling farmers to independently produce and apply biological pesticides in their own rice fields, has become an urgent necessity.

Green Fungus Production Procedure

1. Materials and Equipment

Materials required for producing Metarhizium anisopliae under household conditions include:

• Rice
• Plastic bags (20 × 30 cm)
• A simple inoculation cabinet
• Rubber bands
• Adhesive tape
• Non-absorbent cotton plugs
• Mosquito net fabric
• Sterilization steamer/autoclave
• Alcohol
• Alcohol lamp
• Fuel source
• Primary inoculum (Grade I Metarhizium anisopliae)

2. Preparation of Rice Medium

Rice is soaked in water for approximately 1 to 1.5 hours. After draining, the rice is divided into plastic bags at a rate of 500 g per bag. The bag openings are tightly sealed with rubber bands and covered with an additional layer of plastic to prevent tearing or stretching during sterilization.

Broken rice may be used as an alternative substrate.

Cotton plugs are prepared to cover the openings of the culture bags.

3. Sterilization

Once the water reaches boiling point, the rice bags are placed in a steam sterilizer and sterilized for two hours. After sterilization, the bags are removed and allowed to cool completely.

4. Inoculation of the Fungal Culture

• Use Grade I Metarhizium anisopliae cultures supplied by specialized fungal production facilities. Alternatively, uncontaminated fungus bags previously produced by farmers may be used for subculturing.
• According to researchers at Can Tho University, one fungal culture plate can be divided into six portions.
• Using a small knife or forceps, cut the fungal culture into small pieces.
• Inoculate one portion into a plastic bag containing sterilized rice medium.
• For subculturing, select the first fungus bag showing vigorous green growth 4–5 days after inoculation, free from contamination (without yellow particles or foreign growth).
• One healthy fungus bag can be used to inoculate approximately ten new culture bags.

Benefits of Farm-Scale Green Fungus Production

Producing Metarhizium anisopliae at the household level enables farmers to:

• Proactively produce biological control agents for their own fields.
• Reduce dependence on chemical pesticides.
• Lower production costs.
• Protect environmental quality and human health.
• Preserve beneficial organisms and biodiversity in rice ecosystems.
• Contribute to sustainable agricultural development.

The adoption of green fungus technology represents an effective and environmentally friendly approach to pest management, helping farmers move toward safer, more sustainable, and economically efficient agricultural production systems.