Diseases of field and horticultural crops are one of the most important subjects for BSc Agriculture students, especially from an examination point of view. In internal exams, questions are frequently asked in the form of MCQs, one-liners, and fill-in-the-blank covering major crop diseases, their symptoms, causal organisms, and basic management practices.
This article provides exam-oriented Diseases of field and horticultural crops MCQs with correct answers to help students prepare effectively. The questions are carefully selected from important diseases affecting wheat, sugarcane, mustard, sunflower, cotton, gram, and mango, with consideration for the pattern typically followed by universities and colleges.
If you are preparing for internal exams, semester tests, or quick revision before practicals, these MCQs will help you strengthen your concepts, improve accuracy, and save time during the exam. This post is specially designed for agriculture students who want clear, relevant, and syllabus-focused preparation without unnecessary theory.
Section A: Diseases of field and horticultural crops MCQs
Q1. “Solar Heat Treatment” for control of Loose Smut of wheat was given by:
A) Jensen (1887)
B) Luthra and Sattar (1953)
C) Butler
D) Mehta
Answer: B) Luthra and Sattar (1953)
(Note: Jensen ne Hot Water Treatment diya tha – 1887)
Q2. Which chemical is specifically used for systemic control of Loose Smut?
A) Mancozeb
B) Vitavax (Carboxin)
C) Copper oxychloride
D) Sulphur
Answer: B) Vitavax (Carboxin)
Q3. The “rotten fish” smell in Karnal bunt-infected wheat is due to:
A) Trimethylamine
B) Dimethylamine
C) Ammonia
D) Sulphur dioxide
Answer: A) Trimethylamine
Q4. Tundu disease of wheat is caused by the association of:
A) Fungus + Bacteria
B) Nematode + Fungus
C) Nematode + Bacteria
D) Virus + Aphid
Answer: C) Nematode (Anguina tritici) + Bacteria (Corynebacterium tritici)
Q5. Karnal bunt of wheat was first reported by:
A) Mitra (1931)
B) Butler (1918)
C) Mundkur
D) K.C. Mehta
Answer: A) Mitra (1931)
Q6. Which disease is known as the “Cancer of Wheat”?
A) Loose smut
B) Karnal bunt
C) Black rust
D) Powdery mildew
Answer: B) Karnal bunt
Q7. The causal organism of Loose Smut of wheat is:
A) Tilletia caries
B) Ustilago nuda var. tritici
C) Puccinia graminis
D) Neovossia indica
Answer: B) Ustilago nuda var. tritici
Q8. Loose smut of wheat is:
A) Externally seed-borne
B) Internally seed-borne
C) Soil-borne
D) Air-borne
Answer: B) Internally seed-borne
Section B: Sugarcane Diseases (गन्ना)
Q9. Red rot of sugarcane is caused by:
A) Ustilago scitaminea
B) Colletotrichum falcatum
C) Fusarium moniliforme
D) Ceratocystis paradoxa
Answer: B) Colletotrichum falcatum
Q10. Alcoholic or sour smell from split sugarcane stem is a symptom of:
A) Whip smut
B) Red rot
C) Wilt
D) Grassy shoot
Answer: B) Red rot
Q11. Whip smut of sugarcane converts the central shoot into a:
A) Leafy gall
B) Whip-like black structure
C) Hard knot
D) White powder
Answer: B) Whip-like black structure
Q12. Grassy shoot disease of sugarcane is caused by:
A) Virus
B) Fungus
C) Phytoplasma (MLO)
D) Bacteria
Answer: C) Phytoplasma (MLO)
Q13. The vector of grassy shoot disease is:
A) Whitefly
B) Aphid (Rhopalosiphum maidis)
C) Jassid
D) Thrips
Answer: B) Aphid (Rhopalosiphum maidis)
Q14. “Knife-cut” symptom on sugarcane rind is seen in:
A) Red rot
B) Pokkah boeng
C) Wilt
D) Smut
Answer: B) Pokkah boeng
Q15. Hot water treatment (50°C for 2 hours) is recommended for:
A) Red rot
B) Grassy shoot
C) Ratoon stunting disease
D) All of the above
Answer: D) All of the above
Q16. Pokkah boeng disease is caused by:
A) Fusarium moniliforme
B) Cercospora longipes
C) Ustilago scitaminea
D) Xanthomonas albilineans
Answer: A) Fusarium moniliforme
Section C: Mustard & Sunflower (सरसों और सूरजमुखी)
Q17. “Staghead” formation is a symptom of:
A) Downy mildew of mustard
B) White rust of mustard
C) Powdery mildew
D) Alternaria blight
Answer: B) White rust of mustard
Q18. White rust of mustard is caused by:
A) Peronospora parasitica
B) Albugo candida
C) Alternaria brassicae
D) Erysiphe cruciferarum
Answer: B) Albugo candida
Q19. “Target board effect” on leaves is caused by:
A) Albugo candida
B) Alternaria brassicae
C) Sclerotinia sclerotiorum
D) Fusarium oxysporum
Answer: B) Alternaria brassicae
Q20. Sclerotinia stem rot of sunflower is favored by:
A) High temperature, low humidity
B) Cool weather, high humidity
C) Dry soil
D) Sandy soil
Answer: B) Cool weather, high humidity
Q21. Survival structure of Sclerotinia sclerotiorum is:
A) Oospore
B) Sclerotia
C) Chlamydospore
D) Pycnidia
Answer: B) Sclerotia
Section D: Chickpea Diseases (चना)
Q22. Vascular discoloration in chickpea is a symptom of:
A) Ascochyta blight
B) Wilt
C) Grey mold
D) Rust
Answer: B) Wilt (Fusarium oxysporum)
Q23. Ascochyta blight of chickpea was first reported in India from:
A) Pantnagar
B) Pusa
C) Punjab (1911)
D) Kanpur
Answer: C) Punjab
Q24. Grey mold of chickpea is caused by:
A) Botrytis cinerea
B) Ascochyta rabiei
C) Fusarium udum
D) Rhizoctonia bataticola
Answer: A) Botrytis cinerea
Q25. Internally and externally, the seed-borne disease of chickpea is:
A) Wilt
B) Ascochyta blight
C) Root rot
D) None
Answer: B) Ascochyta blight
Q26. Best management practice for chickpea wilt is:
A) Late sowing
B) Early sowing
C) Deep sowing
D) Resistant varieties
Answer: D) Resistant varieties (e.g., Avrodhi)
Section E: Cotton Diseases (कपास)
Q27. “Black arm” is a stage of:
A) Anthracnose
B) Bacterial blight
C) Root rot
D) Leaf curl
Answer: B) Bacterial blight
Q28. Bacterial blight of cotton is caused by:
A) Xanthomonas axonopodis pv. malvacearum
B) Pseudomonas syringae
C) Ralstonia solanacearum
D) Erwinia amylovora
Answer: A) Xanthomonas axonopodis pv. malvacearum
Q29. Angular leaf spot lesions are delimited by:
A) Leaf margin
B) Veins
C) Midrib
D) Petiole
Answer: B) Veins
Q30. Verticillium wilt of cotton is severe in:
A) Acidic soil
B) Alkaline soil
C) Neutral soil
D) Saline soil
Answer: B) Alkaline soil
Q31. Seed delinting with sulphuric acid controls:
A) Bacterial blight
B) Pink bollworm
C) Leaf curl virus
D) Root rot
Answer: A) Bacterial blight
Q32. “Square rot” and “boll rot” are phases of:
A) Anthracnose
B) Bacterial blight
C) Fusarium wilt
D) Leaf spot
Answer: B) Bacterial blight
Section F: Mango Diseases
Q33. Bunchy top appearance in the mango nursery is due to:
A) Powdery mildew
B) Mango malformation
C) Anthracnose
D) Die back
Answer: B) Mango malformation
Q34. Mango malformation is caused by:
A) Fusarium moniliforme var. subglutinans
B) Colletotrichum gloeosporioides
C) Oidium mangiferae
D) Phoma glomerata
Answer: A) Fusarium moniliforme var. subglutinans
Q35. Powdery mildew of mango survives in:
A) Soil
B) Old leaves and malformed panicles
C) Seeds
D) Water
Answer: B) Old leaves and malformed panicles
Q36. Best fungicide for powdery mildew of mango is:
A) Copper oxychloride
B) Wettable sulphur / Karathane
C) Streptocycline
D) Metalaxyl
Answer: B) Wettable sulphur / Karathane
Q37. Cankerous lesions on mango fruits are caused by:
A) Bacterial blight
B) Anthracnose
C) Red rust
D) Sooty mold
Answer: A) Bacterial blight
Section G: General Plant Pathology
Q38. “Solar Heat Treatment” technique is used to kill pathogens present in:
A) Soil
B) Seed
C) Water
D) Air
✅ Answer: B) Seed
Q39. Trichoderma viride is widely used as a:
A) Chemical fungicide
B) Bio-control agent
C) Bactericide
D) Nematicide
✅ Answer: B) Bio-control agent
Q40. Bordeaux mixture was discovered by:
A) Millardet (1885)
B) Prevost
C) Butler
D) Anton de Bary
✅ Answer: A) Millardet (1885)
Q41. Systemic fungicide Plantvax is mainly effective against:
A) Smuts
B) Rusts
C) Downy mildews
D) Bacterial diseases
✅ Answer: B) Rusts
Q42. Which spore stage of rust fungus is known as the repeating stage?
A) Teleutospore
B) Uredospore
C) Aeciospore
D) Basidiospore
✅ Answer: B) Uredospore
Q43. Downy mildew fungi belong to the class:
A) Ascomycetes
B) Oomycetes
C) Basidiomycetes
D) Deuteromycetes
✅ Answer: B) Oomycetes
Q44. Damping-off disease is most common in:
A) Mature plants
B) Nursery seedlings
C) Post-harvest fruits
D) Flowering stage
✅ Answer: B) Nursery seedlings
Q45. White rust of mustard is essentially a:
A) True rust fungus
B) Downy mildew type disease (Oomycetes)
C) Smut fungus
D) Powdery mildew
✅ Answer: B) Downy mildew type disease (Oomycetes)
Q46. Citrus canker is caused by:
A) Fungus
B) Bacteria (Xanthomonas)
C) Virus
D) Nematode
✅ Answer: B) Bacteria (Xanthomonas)
Q47. For control of bacterial diseases in plants, a commonly used antibiotic is:
A) Penicillin
B) Streptocycline / Agrimycin
C) Carbendazim
D) Mancozeb
✅ Answer: B) Streptocycline / Agrimycin
Q48. “Tirak” is a physiological disorder of:
A) Wheat
B) Cotton
C) Rice
D) Sugarcane
✅ Answer: B) Cotton
Q49. Phytophthora infestans caused which historic famine?
A) Bengal famine (Rice)
B) Irish famine (Potato)
C) Coffee rust epidemic
D) Wheat rust epidemic
✅ Answer: B) Irish famine (Potato)
Q50. Loose smut pathogen survives in wheat seed as:
A) Dormant mycelium in embryo
B) Spores in soil
C) Spores on seed coat
D) Sclerotia
✅ Answer: A) Dormant mycelium in embryo
Section B: Diseases of field and horticultural crops fill in the blanks
Wheat (Gehu)
The leaf blight of wheat caused by Alternaria triticina was first reported by ________ in 1967.
In Loose Smut of wheat, the fungus Ustilago nuda remains dormant in the ________ part of the seed.
The bacterium Corynebacterium tritici causing Tundu disease produces a characteristic ________ slime or gum on the earheads.
Yellow Rust of wheat is caused by the fungus ________.
The systemic fungicide ________ was specifically developed in 1966 for controlling smuts and bunts.
Sugarcane (Ganna)
The perfect stage (sexual stage) of the Red Rot pathogen Colletotrichum falcatum is ________.
In Ratoon Stunting Disease (RSD), the bacterium Clavibacter xyli clogs the ________ vessels of the plant.
The primary mode of transmission for Sugarcane Smut (Ustilago scitaminea) spores is through ________.
________ is the specific fungicide mentioned in notes for treating sett-borne infections like Red Rot.
The wilt of sugarcane is caused by the fungus ________.
Mustard & Sunflower (Sarso/Surajmukhi)
The sexual spore produced by the White Rust fungus (Albugo candida) is known as ________.
Alternaria brassicae conidia are characteristic in shape, having both ________ and ________ septa.
The Downy Mildew fungus Peronospora parasitica is an ________ parasite (nature of parasitism).
In Sunflower, ________ rot causes the stem to shred and form black sclerotia resembling rat excreta.
Albugo candida belongs to the fungal class ________.
Chickpea (Chana)
The perfect stage of Ascochyta rabiei (Blight pathogen) is named ________.
Chickpea Wilt pathogen Fusarium oxysporum survives in the soil primarily as ________.
Grey Mold of chickpea is favored by ________ canopy conditions which trap humidity.
The biological control agent ________ is recommended at 4g/kg for seed treatment against Chickpea Wilt.
In Ascochyta blight, the pycnidia are arranged in ________ circles on the lesions.
Cotton & Mango (Kapas/Aam)
The bacterium Xanthomonas axonopodis pv. malvacearum has a ________ type of flagellum (arrangement).
The “Anthracnose” disease of cotton is caused by ________.
In Mango Malformation, the pathogen produces hormones like ________ which cause deformation.
________ is the toxic substance released by the pathogen in Tundu disease of wheat (mentioned as ‘toxin’).
The physiological disorder of cotton where bolls open badly is known as ________.
Answers
Prabhu and Prasada
Embryo
(It is an embryo-borne infection)Yellow
(Yellow slime disease)Puccinia striiformis
(Stripe / Yellow rust pathogen – implied)Vitavax (Carboxin)
Glomerella tucumanensis
Xylem
Wind
Aretan / Agallol
(Organomercurial seed disinfectants – as mentioned in notes)Cephalosporium sacchari
Oospore
Longitudinal and Transverse septation
(Muriform conidia)Obligate parasite
Sclerotinia / Charcoal
Oomycetes
Mycosphaerella rabiei
Chlamydospores
Dense / Excessive growth
Trichoderma viride
Concentric rings
(Target board effect)Monotrichous flagellation
(Single polar flagellum)Colletotrichum gossypii
Gibberellins / Fusaric acid
(Hormonal imbalance related to malformation – as implied in notes)Corynetoxin
(Associated with Corynebacterium)Tirak
(Bad opening – physiological disorder)
Section- C : Top 20 One-Liner Questions Diseases of field and horticultural crops
Q2. What is the size range of the teliospores of the Karnal Bunt pathogen (Neovossia indica)?
Ans: The teliospores are smooth-walled and measure approximately 22-49 microns in diameter.
Q3. What is the sexual fruiting body of the Wheat Powdery Mildew fungus (Erysiphe graminis) called?
Ans: It is called Cleistothecia (or Cleistothecium), which is a closed, ball-like structure.
Q4. Describe the shape and flagella of the zoospores of the White Rust fungus (Albugo candida).
Ans: The zoospores are kidney-shaped (reniform) and are biflagellate (having two unequal flagella).
Q5. What specific hair-like structures are found in the acervuli of the Red Rot fungus (Colletotrichum falcatum)?
Ans: The acervuli contain long, rigid, black, bristle-like structures called Setae.
Q6. Unlike the alcoholic smell in Red Rot, what kind of odor does a sugarcane plant infected with Wilt emit?
Ans: A split cane infected with Wilt emits a disagreeable odor.
Q7. What are the three distinct phases of Pokkah Boeng disease in Sugarcane?
Ans: The three phases are the Chlorotic Phase, the Top Rot Phase, and the Knife Cut Phase.
Q8. In which specific tissue of the plant are the bacteria of Ratoon Stunting Disease (Clavibacter xyli) found?
Ans: These bacteria are present in the Xylem vessels of the plant.
Q9. Which method is used to separate sclerotia from sunflower seeds in Sclerotinia Rot?
Ans: The Brine Solution (Salt Water) Flotation method is used to remove sclerotia from the seed lot.
Q10. Who gave the name ‘forma specialis ciceri‘ to the Chickpea Wilt pathogen (Fusarium oxysporum)?
Ans: The name was given by Snyder and Hansen in 1940.
Q11. How are the pycnidia arranged on the lesions in Ascochyta Blight of Chickpea?
Ans: The pycnidia are arranged in Concentric Rings on the spots.
Q12. To which fungal class does the Grey Mold pathogen (Botrytis cinerea) belong?
Ans: It belongs to the class Deuteromycotina (Hyphomycetes/Imperfect Fungi).
Q13. What is the nature (gram reaction and shape) of the Cotton Bacterial Blight pathogen?
Ans: The bacterium (Xanthomonas) is Gram-negative, Rod-shaped, and Aerobic.
Q14. Why do the spots in ‘Angular Leaf Spot’ of Cotton appear angular?
Ans: The spots appear angular because the spread of the lesion is restricted by veins and veinlets.
Q15. What are the two main types of symptoms seen in Mango Malformation?
Ans: The two types are Vegetative Malformation (Bunchy Top) and Floral Malformation.
Q16. Which specific antibiotic is recommended for spraying against Bacterial Canker of Mango?
Ans: Streptocycline (or Agrimycin-100) is used for control.
Q17. What does the ‘Yellow Slime’ indicate in Tundu Disease of Wheat?
Ans: It indicates the bacterial oozing of yellow liquid from the affected earheads.
Q18. Where do the symptoms of Mustard Downy Mildew appear first?
ans: Symptoms first appear on the lower surface of the leaves.
Q19. What is a ‘Sclerotia’?
Ans: It is a compact mass of mycelium that serves as a survival or resting structure for the fungus.
Q20. What do the terms ‘Hypertrophy’ and ‘Hyperplasia’ mean in the context of White Rust?
Ans: Hypertrophy refers to the increase in cell size, and Hyperplasia refers to the increase in cell number, leading to malformation.
Top 20 True/False Questions (Plant Pathology)
Wheat: Loose Smut of Wheat is an internally seed-borne disease.
Wheat: The foul smell in Karnal Bunt is caused by Ammonia gas.
Sugarcane: Splitting a cane infected with Red Rot emits an alcoholic or sour smell.
Sugarcane: In Whip Smut disease, the central shoot transforms into a long, whip-like black structure.
Mustard: White Rust disease is caused by the fungus Peronospora parasitica.
Chickpea: The pathogen of Chickpea Wilt survives in the soil as Chlamydospores.
Cotton: Bacterial Blight disease is also known as ‘Black Arm’.
Mango: Mango Malformation is a viral disease.
General: The ‘Solar Heat Treatment’ method was developed by Jensen (1887).
General: Downy Mildew fungi belong to the Class Oomycetes.
Wheat: Tundu disease is caused solely by a Nematode (Anguina tritici).
Sugarcane: The vector for Grassy Shoot Disease (GSD) is the Aphid (Rhopalosiphum maidis).
Mustard: In Alternaria Blight, concentric rings (Target Board effect) are formed on the leaves.
Cotton: Verticillium Wilt is more severe in acidic soils.
Chickpea: Ascochyta Blight disease spreads rapidly in cool temperatures and high humidity.
Mango: Sulphur fungicides (like Karathane) are best for controlling Powdery Mildew.
Sunflower: The sclerotia formed in Sclerotinia Stem Rot resemble rat excreta (rat droppings).
Sugarcane: Ratoon Stunting Disease (RSD) is a bacterial disease.
Wheat: Yellow Rust is also known as ‘Stripe Rust’.
Cotton: ‘Tirak’ is a fungal disease that destroys cotton bolls.
Answers with Explanations
True – The pathogen establishes itself in the embryo of the seed.
False – The foul smell is due to Trimethylamine, not Ammonia.
True – A sour, vinegar-like odor is a diagnostic symptom.
True – The central shoot turns into a dusty black whip.
False – White Rust is caused by Albugo candida. Peronospora causes Downy Mildew.
True – The fungus produces rough-walled chlamydospores for survival.
True – Black Arm is a severe stage of Bacterial Blight affecting the stem.
False – It is a Fungal disease caused by Fusarium moniliforme .
False – Solar Heat Treatment was given by Luthra and Sattar (1953) . Jensen gave Hot Water Treatment.
True – They belong to Oomycetes/Peronosporales.
False – It is caused by an association of a Nematode and a Bacterium (Corynebacterium tritici).
True – The aphid acts as a vector.
True – Concentric rings are a characteristic symptom.
False – Verticillium Wilt is favored by Alkaline Soil, not acidic.
True – Night temperatures of 10°C and high humidity favor the disease.
True – Wettable Sulphur or Karathane is recommended.
True – The sclerotia are black and hard, looking like rat droppings.
True – It is caused by the bacterium Clavibacter xyli.
True – Symptoms appear as yellow stripes.
False – ‘Tirak’ is a Physiological Disorder (bad opening of bolls), not a fungal disease.
Get more MCQs and PYQs
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BSc Ag. Semseter Name | English Notes PDFs |
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2nd semester | |
3rd semester | |
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Also Download Best Agriculture Books
Book Title | Author/Publisher | Availability |
A Competitive Book of Agriculture | Nem Raj Sunda | |
Fundamentals of Agriculture (Vol. 1 & 2) | Arun Katyan | |
Objective Agriculture | S.R. Kantwa | |
Principles of Agronomy | T. Yellamanda Reddy & G.H. Sankara Reddi | |
Introductory Soil Science | D.K. Das | |
Plant Breeding: Principles and Methods | B.D. Singh | |
Textbook of Plant Pathology | P.D. Sharma | |
A Textbook of Entomology | H.S. Bhamrah | |
General Knowledge | Lucent's Publication | |
Animal husbandry | adda |
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