Silkworm Biology

• History of Plant Nematology:
• First Observation of Plant Parasitic Nematodes: In 1743, the English clergyman and naturalist John Turberville Needham crushed blackened wheat grains (cockles) in water and observed moving thread-like organisms under a microscope.
• Identity of the Organism: This organism was the wheat gall nematode, Anguina tritici, marking the very first scientific record and description of a plant parasitic nematode in human history.
• Conclusion: The first plant parasitic nematode was recorded in 1743 (Option 4).

Correct option: (4) 1743

• Phases of Host Plant Selection by Phytophagous Insects:

• Host-habitat finding: Moving to the general plant community guided by light, wind, and broad environmental cues.
• Host finding: Orientation toward individual host plants using visual and volatile olfactory cues.
• Host recognition: Tactile and gustatory assessment of the leaf surface upon landing.
• Host acceptance: Verified by test biting, sap sampling, and ovipositional probing with chemoreceptors on antennae, tarsi, or ovipositor to confirm chemical compatibility.
• Host suitability: Nutritional adequacy supporting insect growth and reproduction.
  • Conclusion: Test biting and ovipositional probing determine Host acceptance (Option 3).

• Mass Production of Trichogramma Egg Parasitoids:
• Laboratory Host: In India, bio-control laboratories and commercial facilities mass-produce egg parasitoids (Trichogramma chilonis, T. japonicum, T. brassicae) exclusively on the eggs of the rice moth, Corcyra cephalonica (family Pyralidae).
• Trichocards: Eggs of Corcyra cephalonica are glued to cards (Tricho-cards), UV-sterilized to prevent host emergence, exposed to Trichogramma adults for parasitization, and dispatched for release against lepidopteran borers in sugarcane, cotton, and rice.
• Conclusion: Exclusively mass-produced on (B) Corcyra cephalonica only (Option 4).

Correct option: (4) (8) only,