Question

Trichogramma species recommended against rice leaf folder is

• A. Trichogramma chilonis
• B. Trichogramma japonicum
• C. Trichogramma brasiliensis
• D. Trichogramma minutum

Hint:

For rice pests, remember this division: Stem Borer = T. japonicum, whereas Leaf Folder = T. chilonis. This is a highly frequent exam question!

Answer 1

The Correct Option is A

Step 1: Understanding the Concept:
Egg parasitoids belonging to the genus Trichogramma (Hymenoptera: Trichogrammatidae) are widely mass-multiplied and released for the biological control of lepidopteran pests.
Different species of Trichogramma exhibit host-searching behaviors and habitat preferences adapted to specific pests and crop microclimates.

Step 2: Detailed Explanation:
In rice ecosystems, two major lepidopteran pests are targeted using different Trichogramma species:
1. Rice Stem Borer (Scirpophaga incertulas): The recommended parasitoid is {Trichogramma japonicum. It is highly adapted to locating stem borer egg masses on rice leaves.
2. Rice Leaf Folder (Cnaphalocrocis medinalis): The recommended parasitoid is {Trichogramma chilonis. It is highly effective at parasitizing the individually laid eggs of the leaf folder moth.
Releasing T. chilonis at the rate of 100,000 to 150,000 parasites per hectare per release (using "trichocards") is a standard recommended biological control practice in Integrated Pest Management (IPM) for rice leaf folder.

Step 3: Final Answer:
Therefore, the Trichogramma species recommended against rice leaf folder is Trichogramma chilonis.