1. Plant pathology is the study of:
(A) Plant diseases
(B) Plant growth
(C) Plant classification
(D) Plant physiology
2. A disease-causing organism is called:
(A) Saprophyte
(B) Pathogen
(C) Symbiont
(D) Vector
3. Which of the following is a biotic cause of plant disease?
(A) Drought
(B) Fungus
(C) Nutrient deficiency
(D) Frost
4. Which of the following is an abiotic cause of plant disease?
(A) Virus
(B) Bacteria
(C) Mineral deficiency
(D) Fungi
5. The study of fungi is called:
(A) Mycology
(B) Bacteriology
(C) Virology
(D) Pathology
6. Which group of pathogens causes rust diseases in plants?
(A) Bacteria
(B) Viruses
(C) Fungi
(D) Nematodes
7. Smut diseases are caused by:
(A) Viruses
(B) Bacteria
(C) Fungi
(D) Protozoa
8. Late blight of potato is caused by:
(A) Alternaria solani
(B) Puccinia graminis
(C) Phytophthora infestans
(D) Ustilago maydis
9. Citrus canker is caused by:
(A) Bacterium
(B) Fungus
(C) Virus
(D) Nematode
10. Which disease is caused by a virus?
(A) Rust of wheat
(B) Smut of maize
(C) Wilt of cotton
(D) Mosaic disease
11. Tobacco mosaic virus mainly attacks:
(A) Roots
(B) Stem
(C) Flowers
(D) Leaves
12. Wilting of plants is commonly caused by:
(A) Viral infection
(B) Fungal infection
(C) All of these
(D) Bacterial infection
13. Which organism causes root-knot disease?
(A) Nematode
(B) Virus
(C) Fungus
(D) Bacteria
14. Nematodes belong to phylum:
(A) Annelida
(B) Nematoda
(C) Arthropoda
(D) Platyhelminthes
15. Powdery mildew appears as:
(A) Black spots
(B) White powdery growth
(C) Yellow streaks
(D) Brown lesions
16. Downy mildew differs from powdery mildew because it grows mainly on:
(A) Upper leaf surface
(B) Roots
(C) Lower leaf surface
(D) Stem only
17. Which disease causes galls in plants?
(A) Tumor disease
(B) Wilt
(C) Canker
(D) Mosaic
18. Crown gall disease is caused by:
(A) Fungus
(B) Virus
(C) Nematode
(D) Bacterium
19. Which bacterium causes crown gall disease?
(A) Clostridium
(B) Rhizobium
(C) Xanthomonas
(D) Agrobacterium tumefaciens
20. Plant viruses are usually transmitted by:
(A) Soil
(B) Air
(C) Water
(D) Insects
21. Aphids commonly transmit:
(A) Fungal diseases
(B) Viral diseases
(C) Bacterial diseases
(D) Nematode diseases
22. Which insect acts as a vector?
(A) Earthworm
(B) Snail
(C) Aphid
(D) Spider
23. Leaf spot disease affects mainly the:
(A) Root
(B) Stem
(C) Flower
(D) Leaf
24. Rust disease of wheat is caused by:
(A) Fusarium oxysporum
(B) Ustilago tritici
(C) Alternaria solani
(D) Puccinia graminis
25. Which disease affects vascular tissues?
(A) Rust
(B) Wilt
(C) Smut
(D) Blight
26. Fusarium wilt is caused by:
(A) Virus
(B) Fungus
(C) Bacterium
(D) Nematode
27. Blight disease results in:
(A) Gradual yellowing
(B) Sudden death of tissues
(C) Tumor formation
(D) Root swelling
28. Early blight of potato is caused by:
(A) Phytophthora
(B) Puccinia
(C) Alternaria
(D) Ustilago
29. Which plant disease spreads rapidly in humid conditions?
(A) Viral diseases
(B) Nematode diseases
(C) Fungal diseases
(D) Mineral deficiency
30. Which method helps prevent plant diseases?
(A) Over-irrigation
(B) Crop rotation
(C) Monoculture
(D) Poor sanitation
31. Removal of infected plants is known as:
(A) Weeding
(B) Pruning
(C) Rogueing
(D) Harvesting
32. Use of disease-resistant varieties is an example of:
(A) Chemical control
(B) Biological control
(C) Mechanical control
(D) Genetic control
33. Which chemical is commonly used to control fungal diseases?
(A) Insecticide
(B) Fungicide
(C) Herbicide
(D) Nematicide
34. Bordeaux mixture is used to control:
(A) Viral diseases
(B) Fungal diseases
(C) Bacterial diseases
(D) Nematode diseases
35. Which disease shows mosaic pattern on leaves?
(A) Rust
(B) Wilt
(C) Blight
(D) Mosaic disease
36. Chlorosis in plants indicates deficiency of:
(A) Iron
(B) Potassium
(C) Calcium
(D) Sulphur
37. Which nutrient deficiency causes leaf scorching?
(A) Potassium
(B) Nitrogen
(C) Magnesium
(D) Phosphorus
38. Seed treatment helps in controlling:
(A) Airborne diseases
(B) Soil-borne diseases
(C) Viral diseases
(D) Physiological diseases
39. Which pathogen lacks cellular structure?
(A) Bacteria
(B) Fungus
(C) Virus
(D) Nematode
40. Viral diseases cannot be controlled by:
(A) Resistant varieties
(B) Vector control
(C) Quarantine
(D) Fungicides
41. Quarantine is used to prevent:
(A) Spread of insects
(B) Spread of diseases
(C) Soil erosion
(D) Water pollution
42. Which practice reduces disease incidence in crops?
(A) Dense planting
(B) Flood irrigation
(C) Over-fertilization
(D) Crop rotation
43. Which disease causes black powdery masses in grains?
(A) Rust
(B) Wilt
(C) Blight
(D) Smut
44. Which pathogen survives in soil for long periods?
(A) Virus
(B) Algae
(C) Bacterium
(D) Fungus
45. The sudden death of seedlings is called:
(A) Wilt
(B) Blight
(C) Damping-off
(D) Canker
46. Damping-off disease mostly affects:
(A) Mature plants
(B) Seeds and seedlings
(C) Fruits
(D) Flowers
47. Which disease causes sunken lesions on stems?
(A) Rust
(B) Mosaic
(C) Canker
(D) Smut
48. Which environmental condition favors bacterial diseases?
(A) Dry weather
(B) Low humidity
(C) Cold temperature
(D) High moisture
49. Integrated disease management involves:
(A) Only chemicals
(B) Only resistant varieties
(C) No control measures
(D) Combination of methods
50. The main aim of plant pathology is to:
(A) Increase pollution
(B) Control plant diseases
(C) Study plant anatomy
(D) Classify plants