Trichogramma Wasp (Indian)
Trichogramma chilonis
📖 Description
Trichogramma chilonis is the most widely used biocontrol agent in Indian agriculture, with annual releases on over 5 million hectares of cotton, sugarcane, rice, vegetables and pulses. This tiny egg parasitoid (less than 1 mm long) lays its eggs inside the eggs of pest caterpillars — the Trichogramma larva develops inside, killing the pest egg before it can hatch into a damaging caterpillar. Tricho-cards (parasitized Corcyra eggs glued to cardboard strips) are mass-produced by state biocontrol labs and ICAR institutions, and are commercially available to farmers at low cost (Rs. 30-50 per card). IPM programs in Punjab, Andhra Pradesh, Tamil Nadu and Maharashtra have demonstrated that consistent Trichogramma releases reduce insecticide use by 30-50% while maintaining or improving yields. Trichogramma is the cornerstone of sustainable caterpillar pest management in Indian agriculture.
⚠️ Symptoms to watch for
- No damage to crops (beneficial).
- Parasitized host eggs turn black, preventing caterpillar emergence.
- Effective release reduces pest populations 40-80% and reduces insecticide need 30-50%.
🩹 Treatment
- No treatment needed — this is a beneficial insect used in biocontrol.
- For field release: purchase Tricho-cards (each contains ~10000 parasitized Corcyra eggs), cut into strips, place 5-6 strips per acre at canopy height, release at 7-10 day intervals from pest initiation.
🌿 Organic treatments
- Trichogramma is itself organic — Tricho-card release @ 50000-100000/ha per release, 4-6 releases at 7-10 day intervals starting at pest initiation, repeat as needed based on pest pressure.
- Combine with NSKE, Bt or NPV for synergistic effect.
- Avoid chemical insecticides that kill Trichogramma.
🧪 Chemical treatments
- Generally avoided — most chemical insecticides are toxic to Trichogramma.
- If pest pressure exceeds biocontrol capacity, use selective insecticides (Bt, NPV, Spinosad, Indoxacarb) that have lower impact on Trichogramma.
- Avoid organophosphates, pyrethroids and neonicotinoids during release period.
🛡️ Prevention
- Conserve native Trichogramma by avoiding broad-spectrum insecticides
- maintain field margins with flowering plants (fennel, coriander, mustard) to provide nectar for adults
- release augmented Trichogramma at 7-10 day intervals during pest season
- store Tricho-cards at cool temperature (10-15°C) and use within 2-3 days of receipt
🪴 Affected plants
- Targets eggs of: Cotton Bollworms (Helicoverpa, Pectinophora)
- Sugarcane Borers (Chilo, Scirpophaga)
- Rice Stem Borers (Scirpophaga, Chilo)
- Castor Semilooper
- Brinjal Fruit & Shoot Borer
- Cabbage Diamondback Moth
- Tomato Fruit Borer
- Pomegranate Anar Butterfly
🦋 Natural predators
- Predatory mites and ants may attack emerging adults
- otherwise Trichogramma has few natural enemies in field
🌱 Host plants
- Any crop attacked by caterpillar pests — parasitoid's host range covers eggs of 200+ Lepidopteran species
🔄 Lifecycle
- Female lays 1-50 eggs inside host eggs (1 Trichogramma egg per host egg).
- Larva feeds inside host egg for 3-5 days.
- Pupation inside host egg, lasting 3-5 days.
- Adult lifespan 5-15 days.
- Total life cycle 7-12 days; 30-40 generations per year.
- Each female parasitizes 20-80 host eggs.
📅 Season
- Released during pest season (varies by crop and pest — cotton Jun-Dec, sugarcane May-Nov, rice Aug-Nov, vegetables year-round)
🔎 Appearance
- Adult is a tiny, yellowish-brown micro-wasp with red eyes and fringed wings.
- Females are slightly larger than males.
- Larvae are tiny, legless, white grubs that develop inside host eggs (invisible without dissection).
- Pupae develop inside the host egg, which turns black when parasitized.
💥 Damage level
- Beneficial
🔁 Reproduction rate
- Very Rapid
🗺️ Geographic regions
- Indian Subcontinent
- South Asia
- Worldwide Biocontrol Use
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