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Plant Pathology & Crop Protection (Agriculture & Crop Sciences) Solved Questions & Notes (2026) - Apex Rankers

Agricultural & Veterinary Sciences > Agriculture & Crop Sciences > Plant Pathology & Crop Protection

100 Total Questions
~150 mins Read Time
1 Subject Areas
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Q. 1 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
Karnal bunt of wheat is caused by which fungal pathogen?
A
Tilletia indica (Neovossia indica)
✓ Correct
B
Puccinia striiformis
C
Ustilago tritici
D
Fusarium oxysporum
💡 Step-by-Step Explanation & Concept Rationale
Tilletia indica infects wheat florets, converting kernels into fishy-smelling teliospores.
Q. 2 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
Cotton Leaf Curl Disease (CLCuD) is caused by a begomovirus transmitted by:
A
Jassids
B
Thrips
C
Whitefly (Bemisia tabaci)
✓ Correct
D
Aphids
💡 Step-by-Step Explanation & Concept Rationale
Bemisia tabaci vector persistently transmits CLCuV, causing leaf curling and enations.
Q. 3 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
Late blight of potato is caused by which oomycete organism?
A
Pythium aphanidermatum
B
Phytophthora infestans
✓ Correct
C
Alternaria solani
D
Rhizoctonia solani
💡 Step-by-Step Explanation & Concept Rationale
Phytophthora infestans rapidly blights foliage and causes brown tuber rot in cool moist weather.
Q. 4 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
Bordeaux mixture is a protective fungicide composed of:
A
Zinc sulfate and urea
B
Iron sulfate and lime
C
Copper sulfate and Slaked lime (CuSO4 + Ca(OH)2)
✓ Correct
D
Copper oxychloride and sulfur
💡 Step-by-Step Explanation & Concept Rationale
Bordeaux mixture precipitates copper hydroxide, providing broad-spectrum protective fungicidal action.
Q. 5 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
Citrus canker is a quarantine bacterial disease caused by:
A
Ralstonia solanacearum
B
Erwinia amylovora
C
Pseudomonas syringae
D
Xanthomonas citri subsp. citri
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
Xanthomonas citri causes raised corky lesions with oily halos on citrus leaves and fruits.
Q. 6 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
Loose smut of wheat is internally seed-borne and caused by:
A
Puccinia graminis
B
Septoria tritici
C
Tilletia caries
D
Ustilago tritici
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
Ustilago tritici mycelium resides dormant inside the embryo of infected seeds.
Q. 7 MULTIPLE_CHOICE
Difficulty: HARD (1 Mark)
Which systemic fungicide is widely used as a seed dressing to control loose smut of wheat?
A
Carboxin / Tebuconazole / Difenoconazole
✓ Correct
B
Sulfur powder
C
Bordeaux mixture
D
Copper sulfate
💡 Step-by-Step Explanation & Concept Rationale
Systemic triazoles and carboxin penetrate the germinating seed to eradicate internal fungal mycelium.
Q. 8 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
Root-knot nematodes belong to which genus?
A
Pratylenchus species
B
Xiphinema species
C
Meloidogyne species
✓ Correct
D
Heterodera species
💡 Step-by-Step Explanation & Concept Rationale
Meloidogyne juveniles invade root tips, inducing giant cells and characteristic root galls.
Q. 9 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
The 'Disease Triangle' concept states that plant disease development requires:
A
Host and fertilizer only
B
A susceptible host, a virulent pathogen, and a favorable environment
✓ Correct
C
Only seed and water
D
Only pathogen and soil
💡 Step-by-Step Explanation & Concept Rationale
Disease manifests only when all three components interact favorably over time.
Q. 10 MULTIPLE_CHOICE
Difficulty: HARD (1 Mark)
Which fungal group produces sexual spores inside a sac called an ascus?
A
Ascomycota
✓ Correct
B
Zygomycota
C
Basidiomycota
D
Oomycota
💡 Step-by-Step Explanation & Concept Rationale
Ascomycetes produce 8 ascospores within a specialized microscopic sac called an ascus.
Q. 11 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In applied field conditions: Karnal bunt of wheat is caused by which fungal pathogen?
A
Fusarium oxysporum
B
Tilletia indica (Neovossia indica)
✓ Correct
C
Ustilago tritici
D
Puccinia striiformis
💡 Step-by-Step Explanation & Concept Rationale
Tilletia indica infects wheat florets, converting kernels into fishy-smelling teliospores.
Q. 12 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
In applied field conditions: Cotton Leaf Curl Disease (CLCuD) is caused by a begomovirus transmitted by:
A
Thrips
B
Aphids
C
Jassids
D
Whitefly (Bemisia tabaci)
✓ Correct
💡 Step-by-Step Explanation & Concept Rationale
Bemisia tabaci vector persistently transmits CLCuV, causing leaf curling and enations.
Q. 13 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
In applied field conditions: Late blight of potato is caused by which oomycete organism?
A
Alternaria solani
B
Phytophthora infestans
✓ Correct
C
Rhizoctonia solani
D
Pythium aphanidermatum
💡 Step-by-Step Explanation & Concept Rationale
Phytophthora infestans rapidly blights foliage and causes brown tuber rot in cool moist weather.
Q. 14 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In applied field conditions: Bordeaux mixture is a protective fungicide composed of:
A
Iron sulfate and lime
B
Copper sulfate and Slaked lime (CuSO4 + Ca(OH)2)
✓ Correct
C
Zinc sulfate and urea
D
Copper oxychloride and sulfur
💡 Step-by-Step Explanation & Concept Rationale
Bordeaux mixture precipitates copper hydroxide, providing broad-spectrum protective fungicidal action.
Q. 15 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In applied field conditions: Citrus canker is a quarantine bacterial disease caused by:
A
Erwinia amylovora
B
Xanthomonas citri subsp. citri
✓ Correct
C
Pseudomonas syringae
D
Ralstonia solanacearum
💡 Step-by-Step Explanation & Concept Rationale
Xanthomonas citri causes raised corky lesions with oily halos on citrus leaves and fruits.
Q. 16 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In applied field conditions: Loose smut of wheat is internally seed-borne and caused by:
A
Ustilago tritici
✓ Correct
B
Puccinia graminis
C
Septoria tritici
D
Tilletia caries
💡 Step-by-Step Explanation & Concept Rationale
Ustilago tritici mycelium resides dormant inside the embryo of infected seeds.
Q. 17 MULTIPLE_CHOICE
Difficulty: HARD (1 Mark)
In applied field conditions: Which systemic fungicide is widely used as a seed dressing to control loose smut of wheat?
A
Sulfur powder
B
Carboxin / Tebuconazole / Difenoconazole
✓ Correct
C
Bordeaux mixture
D
Copper sulfate
💡 Step-by-Step Explanation & Concept Rationale
Systemic triazoles and carboxin penetrate the germinating seed to eradicate internal fungal mycelium.
Q. 18 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In applied field conditions: Root-knot nematodes belong to which genus?
A
Meloidogyne species
✓ Correct
B
Xiphinema species
C
Heterodera species
D
Pratylenchus species
💡 Step-by-Step Explanation & Concept Rationale
Meloidogyne juveniles invade root tips, inducing giant cells and characteristic root galls.
Q. 19 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
In applied field conditions: The 'Disease Triangle' concept states that plant disease development requires:
A
A susceptible host, a virulent pathogen, and a favorable environment
✓ Correct
B
Only pathogen and soil
C
Only seed and water
D
Host and fertilizer only
💡 Step-by-Step Explanation & Concept Rationale
Disease manifests only when all three components interact favorably over time.
Q. 20 MULTIPLE_CHOICE
Difficulty: HARD (1 Mark)
In applied field conditions: Which fungal group produces sexual spores inside a sac called an ascus?
A
Zygomycota
B
Ascomycota
✓ Correct
C
Basidiomycota
D
Oomycota
💡 Step-by-Step Explanation & Concept Rationale
Ascomycetes produce 8 ascospores within a specialized microscopic sac called an ascus.
Q. 21 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In agricultural practice: Karnal bunt of wheat is caused by which fungal pathogen?
A
Tilletia indica (Neovossia indica)
✓ Correct
B
Puccinia striiformis
C
Fusarium oxysporum
D
Ustilago tritici
💡 Step-by-Step Explanation & Concept Rationale
Tilletia indica infects wheat florets, converting kernels into fishy-smelling teliospores.
Q. 22 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
In agricultural practice: Cotton Leaf Curl Disease (CLCuD) is caused by a begomovirus transmitted by:
A
Thrips
B
Whitefly (Bemisia tabaci)
✓ Correct
C
Aphids
D
Jassids
💡 Step-by-Step Explanation & Concept Rationale
Bemisia tabaci vector persistently transmits CLCuV, causing leaf curling and enations.
Q. 23 MULTIPLE_CHOICE
Difficulty: EASY (1 Mark)
In agricultural practice: Late blight of potato is caused by which oomycete organism?
A
Rhizoctonia solani
B
Pythium aphanidermatum
C
Phytophthora infestans
✓ Correct
D
Alternaria solani
💡 Step-by-Step Explanation & Concept Rationale
Phytophthora infestans rapidly blights foliage and causes brown tuber rot in cool moist weather.
Q. 24 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In agricultural practice: Bordeaux mixture is a protective fungicide composed of:
A
Iron sulfate and lime
B
Copper oxychloride and sulfur
C
Copper sulfate and Slaked lime (CuSO4 + Ca(OH)2)
✓ Correct
D
Zinc sulfate and urea
💡 Step-by-Step Explanation & Concept Rationale
Bordeaux mixture precipitates copper hydroxide, providing broad-spectrum protective fungicidal action.
Q. 25 MULTIPLE_CHOICE
Difficulty: MEDIUM (1 Mark)
In agricultural practice: Citrus canker is a quarantine bacterial disease caused by:
A
Xanthomonas citri subsp. citri
✓ Correct
B
Ralstonia solanacearum
C
Pseudomonas syringae
D
Erwinia amylovora
💡 Step-by-Step Explanation & Concept Rationale
Xanthomonas citri causes raised corky lesions with oily halos on citrus leaves and fruits.
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