Plant Protection: Major Crop Pests, Plant Pathogens & Integrated Pest Management (IPM) - Water Science and Technology | Agrigyan

Etiology of rice dwarfing diseases:
Rice dwarfing diseases (such as Southern Rice Black-Streaked Dwarf Virus - SRBSDV and Rice Dwarf Virus - RDV) are caused by plant pathogenic viruses (family Reoviridae, genus Fijivirus / Phytoreovirus).
SRBSDV emerged recently causing severe stunting/dwarfing of paddy crops across Northern India (Punjab, Haryana, UP) and is transmitted persistently by the white-backed planthopper (Sogatella furcifera).
Symptoms include severe plant stunting, dark green leaves, and failure of panicle emergence.

Epidemiology and Management of Karnal Bunt of Wheat:

• Statement (I) is True: Karnal bunt, caused by the smut fungus Tilletia indica (syn. Neovossia indica), was first discovered and reported by Mitra in 1931 from Karnal, Haryana, India. It produces a characteristic rotten fish odor (due to trimethylamine).
• Statement (II) is True: Standard integrated management recommendations include deploying resistant cultivars (e.g., HD 2967, PBW 502) and treating foundation seeds with systemic fungicides like Vitavax (carboxin) or thiram at $2 - 2.5\text{ g/kg}$ seed to destroy seed-borne teliospores.

Matching Major Crop Pests and Pathogens:

• Sugarcane matches with (III) Red rot (Colletotrichum falcatum): The cancer of sugarcane causing vascular reddening and alcoholic smell.
• Chickpea matches with (IV) Pod borer (Helicoverpa armigera): Destructive caterpillar boring holes into developing legume pods.
• Cotton matches with (I) American bollworm (Helicoverpa armigera): Primary boll-damaging pest of cotton crops.
• Rice matches with (II) Neck blast (Magnaporthe oryzae / Pyricularia oryzae): Attacks the panicle base node resulting in unfilled chaffy grains.