Plant Bacteriology

• Citrus Nematode (Tylenchulus semipenetrans) Biology:
• Egg Sac Gelatinous Matrix: Sedentary mature females of Tylenchulus semipenetrans remain semi-endoparasitic in citrus feeder roots. They secrete a protective gelatinous matrix into which eggs are deposited.
• Secretion Site: In Tylenchulus semipenetrans, the gelatinous matrix is uniquely secreted through the excretory pore, located anteriorly near the vulva.
• Contrast with Root-Knot Nematodes: In Meloidogyne (root-knot nematodes), the gelatinous matrix is secreted by six rectal glands. Tylenchulus lacks caudal glands; Statement I is correct and Statement II is incorrect (Option 3).

• Status of Indian Wildlife and Fauna:
• Statement (I) is true: The House Sparrow (Passer domesticus) is an omnivorous bird feeding on seeds, grains, and insects whose populations have declined rapidly due to urbanization, pesticide use, and lack of nesting sites, prompting nationwide conservation efforts (e.g., State Bird of Delhi, World Sparrow Day).
• Statement (II) is evaluated: Nilgai or Blue bull (Boselaphus tragocamelus) is the largest Asian antelope. In the examination key, Statement II was marked incorrect because it is an antelope rather than a member of the domestic cattle/cow genus (Bos).
• Conclusion: Statement (I) is correct but Statement (II) is incorrect (Option 3).

• Oviposition and Parasitization of Cereal Stem Borers:
• Statement (I) is correct: The spotted stem borer (Chilo partellus) lays its flat, scale-like oval eggs in overlapping clusters/patches (resembling fish scales, 20–50 eggs per batch) on the underside of maize and sorghum leaves.
• Statement (II) is correct: Eggs of the pink stem borer (Sesamia inferens) laid beneath the leaf sheath are heavily parasitized by scelionid egg parasitoid wasps (genus Telenomus, family Scelionidae).
• Conclusion: Both Statement (I) and Statement (II) are correct (Option 1).

• Major Sucking Pests of Cotton:
• Target Pests of Cotton:
• Aphis gossypii: The cotton aphid (melon aphid), a major pest causing crinkling and leaf curling and secreting honeydew.
• Phenacoccus solenopsis: The invasive cotton mealybug, causing devastating economic losses to Bt cotton across India.
• Other Aphids Listed:
• (A) Lipaphis erysimi: Mustard aphid, infests cruciferous crops.
• (D) Aphis craccivora: Cowpea aphid, infests pulses and legumes.
• Conclusion: Insects infesting cotton are (B) and (C) only (Option 2).

Correct option: (2) (B) and (C) only.