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MCQ on Terms and concepts in plant pathology
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MCQ on Terms and concepts in plant pathology
MCQ on Terms and concepts in plant pathology
Plant Pathology MCQ E-Books Download1. What is plant pathology?
A) Study of biotic and abiotic agents causing diseases in plants
B) Study of plant growth
C) Study of plant reproduction
D) Study of plant nutrition
Answer: A) Study of biotic and abiotic agents causing diseases in plants
2. Which disease caused the Irish Potato Famine in 1845?
A) Dutch Elm Disease
B) Chestnut Blight
C) Phytophthora Late Blight
D) Apple Scab
Answer: C) Phytophthora Late Blight
3. What is the estimated death toll from the Irish Potato Famine?
A) 500,000
B) 1.5 million
C) 2 million
D) 200,000
Answer: B) 1.5 million
4. Which of the following plant diseases has had the greatest economic impact in America?
A) Dutch Elm Disease
B) Potato Blight
C) Tomato Wilt
D) Rice Blast
Answer: A) Dutch Elm Disease
5. What defines a plant disease?
A) A result of continuous irritation of plant tissues by a primary causal agent
B) A single event that damages the plant
C) Only caused by abiotic agents
D) A result of genetic mutations in plants
Answer: A) A result of continuous irritation of plant tissues by a primary causal agent
6. What is the difference between biotic and abiotic diseases?
A) Biotic diseases are caused by living organisms, while abiotic diseases are non-living agents
B) Abiotic diseases are caused by microorganisms
C) Biotic diseases involve temperature extremes
D) Abiotic diseases are always fatal
Answer: A) Biotic diseases are caused by living organisms, while abiotic diseases are non-living agents
7. What are examples of biotic pathogens in plants?
A) Temperature extremes
B) Excess soil moisture
C) Fungi, bacteria, viruses, nematodes
D) Air pollution
Answer: C) Fungi, bacteria, viruses, nematodes
8. What is a parasite in plant pathology?
A) An organism that feeds on non-living organic matter
B) An organism that feeds and reproduces on living plant material
C) A plant that causes mechanical damage
D) A microorganism that helps plants grow
Answer: B) An organism that feeds and reproduces on living plant material
9. What is an obligate parasite?
A) A pathogen that can survive on non-living organic matter
B) A pathogen that requires living plant material to grow and reproduce
C) A plant that does not cause disease
D) A saprophyte that feeds on decaying plant material
Answer: B) A pathogen that requires living plant material to grow and reproduce
10. What is a saprophyte?
A) An organism that feeds on living plants
B) An organism that feeds on non-living organic matter
C) A pathogenic organism causing diseases in plants
D) A plant that assists in the disease process
Answer: B) An organism that feeds on non-living organic matter
11. Which of the following is an example of an abiotic disease?
A) Powdery mildew
B) Ozone injury
C) Bacterial wilt
D) Fusarium root rot
Answer: B) Ozone injury
12. What is the primary requirement for a plant disease to occur?
A) A high level of air pollution
B) A susceptible host, active pathogen, and a suitable environment
C) Only the presence of a pathogen
D) Temperature extremes
Answer: B) A susceptible host, active pathogen, and a suitable environment
13. Which of the following factors does NOT contribute to the disease triangle?
A) Susceptible host plant
B) Active pathogen
C) Suitable environment for the pathogen
D) Rainfall
Answer: D) Rainfall
14. What does the “disease triangle” represent?
A) The interactions between host, pathogen, and environment
B) The types of plant diseases
C) The age of the plant
D) The stages of pathogen development
Answer: A) The interactions between host, pathogen, and environment
15. What happens if one of the legs of the disease triangle is broken?
A) The plant will become resistant to disease
B) Disease cannot occur
C) The pathogen will grow stronger
D) The disease will spread faster
Answer: B) Disease cannot occur
16. Which of the following is a noninfectious (abiotic) disease?
A) Black rot
B) Nutrient deficiencies
C) Tomato blight
D) Rice blast
Answer: B) Nutrient deficiencies
17. What is the role of toxins produced by a plant parasite?
A) To help the plant resist infection
B) To disturb the normal metabolic processes in the plant
C) To protect the plant from environmental stress
D) To promote healthy growth
Answer: B) To disturb the normal metabolic processes in the plant
18. Which disease caused significant economic losses to chestnut trees in the United States?
A) Dutch Elm Disease
B) Chestnut Blight
C) Phytophthora Late Blight
D) Pine Wilt Disease
Answer: B) Chestnut Blight
19. What is the key difference between biotic and abiotic diseases?
A) Biotic diseases are caused by pathogens; abiotic diseases are caused by environmental factors
B) Biotic diseases are caused by environmental stress
C) Abiotic diseases are caused by microorganisms
D) Biotic diseases only affect certain plants, while abiotic diseases affect all plants
Answer: A) Biotic diseases are caused by pathogens; abiotic diseases are caused by environmental factors
20. What is the main function of the “disease triangle” in plant pathology?
A) To determine the most dangerous pathogens
B) To identify the environmental conditions required for disease
C) To study the evolution of plant diseases
D) To explain the necessary conditions for disease development
Answer: D) To explain the necessary conditions for disease development
21. Which of the following is an example of a parasitic plant pathogen?
A) Fungi
B) Viruses
C) Phytoplasmas
D) Mistletoe
Answer: D) Mistletoe
22. What is the effect of air pollution on plants?
A) Increases growth
B) Causes leaf injury
C) Improves plant health
D) Reduces photosynthesis
Answer: B) Causes leaf injury
23. How can pathogens with saprophytic ability be cultured?
A) In soil rich in organic matter
B) On living plant material
C) In a laboratory with a host plant
D) On synthetic media designed for saprophytes
Answer: A) In soil rich in organic matter
24. What is an example of a mechanical cause of abiotic plant disease?
A) Excess moisture
B) Ozone damage
C) Girdling from roots or twine
D) Iron deficiency
Answer: C) Girdling from roots or twine
25. Which of the following factors is NOT part of the disease triangle?
A) Presence of a susceptible host
B) Presence of a pathogen
C) Temperature variations
D) A suitable environment
Answer: C) Temperature variations
26. What happens when a plant is infected by a parasite?
A) It grows stronger
B) It produces more fruit
C) The parasite weakens the plant and may block nutrient flow
D) The plant’s metabolism is unaffected
Answer: C) The parasite weakens the plant and may block nutrient flow
27. What type of pathogen is most responsible for infectious plant diseases?
A) Viruses
B) Nematodes
C) Bacteria
D) Microbes
Answer: D) Microbes
28. What causes mechanical damage to plants?
A) High humidity
B) Girdling by roots or injury from twine
C) Excessive soil acidity
D) High temperatures
Answer: B) Girdling by roots or injury from twine
29. Which factor is NOT necessary for disease to occur?
A) A susceptible host
B) An active pathogen
C) Suitable environmental conditions
D) An infected plant from a different region
Answer: D) An infected plant from a different region
30. What role do environmental conditions play in plant diseases?
A) They are irrelevant to disease development
B) They are only important for abiotic diseases
C) They interact with pathogens and host plants to promote disease
D) They only affect the spread of disease
Answer: C) They interact with pathogens and host plants to promote disease
31. What is the primary cause of plant diseases?
A) Mechanical damage
B) Abiotic factors
C) Pathogens
D) Soil deficiencies
Answer: C) Pathogens
32. Which of the following best describes plant pathology?
A) The study of plant growth patterns
B) The study of plant diseases caused by biotic and abiotic factors
C) The study of soil chemistry
D) The study of plant genetics
Answer: B) The study of plant diseases caused by biotic and abiotic factors
33. What is a characteristic of noninfectious (abiotic) diseases?
A) They are caused by microorganisms
B) They do not spread from one plant to another
C) They are caused by living organisms
D) They occur only in tropical climates
Answer: B) They do not spread from one plant to another
34. What type of disease is caused by a parasite that feeds on living plant tissue?
A) Noninfectious disease
B) Saprophytic disease
C) Infectious disease
D) Nutrient deficiency disease
Answer: C) Infectious disease
35. Which of the following is an example of an abiotic disease?
A) Powdery mildew
B) Chestnut blight
C) Iron deficiency
D) Dutch elm disease
Answer: C) Iron deficiency
36. What is the disease triangle?
A) A diagram representing plant growth stages
B) A model used to understand the interaction between the host, pathogen, and environment
C) A classification system for plant pathogens
D) A way to predict weather conditions for plant diseases
Answer: B) A model used to understand the interaction between the host, pathogen, and environment
37. Which factor is NOT required for disease to occur according to the disease triangle?
A) Susceptible host
B) Active pathogen
C) Favorable environment
D) Plant resistance
Answer: D) Plant resistance
38. What is a major characteristic of fungi?
A) They can make their own food through photosynthesis
B) They are single-celled organisms
C) They are multicellular organisms made of mycelium
D) They reproduce sexually only
Answer: C) They are multicellular organisms made of mycelium
39. Which of the following is NOT a method of reproduction for fungi?
A) Spores
B) Sclerotia
C) Mycelial fragments
D) Binary fission
Answer: D) Binary fission
40. Fungal spores that are capable of surviving adverse conditions for many years are called:
A) Conidia
B) Sclerotia
C) Zoospores
D) Mycelia
Answer: B) Sclerotia
41. Which fungal structure allows for the spread of disease by air currents?
A) Rhizomorphs
B) Conidiophores
C) Mycelial fragments
D) Sclerotia
Answer: B) Conidiophores
42. Fungal spores are often spread by:
A) Birds
B) Wind, insects, and rain
C) Soil bacteria
D) Temperature changes
Answer: B) Wind, insects, and rain
43. How do some fungi penetrate plant tissue?
A) By using natural openings like stomata
B) By producing toxins that break down cell walls
C) Through direct penetration using enzymes
D) All of the above
Answer: D) All of the above
44. What is a typical symptom of fungal infection in plants?
A) Yellowing of the leaves due to nutrient deficiencies
B) Wilting due to lack of water
C) Distorted leaves or fruit due to viral infections
D) Reduced yield and quality of plant products
Answer: D) Reduced yield and quality of plant products
45. Which environmental factor is most important for fungal spore germination?
A) Moisture
B) Temperature
C) Soil pH
D) Light
Answer: A) Moisture
46. Bacterial plant pathogens reproduce primarily by:
A) Binary fission
B) Spore formation
C) Fragmentation of mycelium
D) Sexual reproduction
Answer: A) Binary fission
47. Which of the following is a major method of bacterial disease spread?
A) Wind
B) Blowing rain
C) Soil erosion
D) Root decay
Answer: B) Blowing rain
48. What is the primary means of spreading fire blight of apple and pear?
A) Soil contact
B) Insect vectors
C) Airborne spores
D) Water droplets
Answer: B) Insect vectors
49. Viruses can only replicate inside:
A) Soil particles
B) Plant cells
C) Insects
D) Bacterial cells
Answer: B) Plant cells
50. Virus diseases can be spread by:
A) Insects
B) Wind
C) Water
D) All of the above
Answer: D) All of the above
51. Which virus transmission method involves the use of tools or human contact?
A) Seed transmission
B) Mechanical transmission
C) Airborne transmission
D) Waterborne transmission
Answer: B) Mechanical transmission
52. Which of the following is a common symptom of viral infections in plants?
A) Yellowing of leaves and reduced growth
B) Leaf curling or distortion
C) Mottling or streaking of leaves
D) All of the above
Answer: D) All of the above
53. Which fungal disease is known for infecting apple trees?
A) Black rot
B) Powdery mildew
C) Apple scab
D) Leaf spot
Answer: C) Apple scab
54. What is the role of conidiophores in fungal reproduction?
A) To produce sexual spores
B) To produce asexual spores (conidia)
C) To spread spores through wind
D) To protect fungal spores from harsh conditions
Answer: B) To produce asexual spores (conidia)
55. What environmental condition favors fungal spore release?
A) Dry, warm weather
B) High humidity and moisture
C) Cold, snowy weather
D) High light exposure
Answer: B) High humidity and moisture
56. Which is a common symptom of bacterial infection in plants?
A) Mottled leaves
B) Wilted roots
C) Soft rot and ooze from infected tissues
D) Blistering of fruits
Answer: C) Soft rot and ooze from infected tissues
57. In which condition would a fungal pathogen be most active?
A) In a dry and cold environment
B) In a moist and warm environment
C) In areas with high light levels
D) In arid climates
Answer: B) In a moist and warm environment
58. How do viruses disrupt plant cells?
A) By producing toxins
B) By breaking down plant cell walls
C) By altering normal cell functions
D) By blocking the flow of water in plant tissues
Answer: C) By altering normal cell functions
59. What is a typical characteristic of viral infection in plants?
A) Formation of dark spots
B) Rapid wilting of leaves
C) Streaks or mosaics on leaves
D) Soft and watery fruit
Answer: C) Streaks or mosaics on leaves
60. Which of the following pathogens is known to cause damping-off disease?
A) Rhizoctonia
B) Fusarium
C) Pythium
D) Both A and C
Answer: D) Both A and C
Plant Pathology MCQ E-Books Download61. What is the main characteristic of a fungus?
A) It is a unicellular organism
B) It is made up of mycelium
C) It can photosynthesize
D) It is a type of bacteria
Answer: B) It is made up of mycelium
62. How do fungi reproduce?
A) By seeds
B) By spores, sclerotia, and mycelial fragments
C) By cloning
D) By budding
Answer: B) By spores, sclerotia, and mycelial fragments
63. What do fungal spores resemble in function?
A) Roots
B) Seeds in higher plants
C) Leaves
D) Stems
Answer: B) Seeds in higher plants
64. Which of the following is an example of a fungus that forms sclerotia?
A) Penicillium
B) Rhizoctonia
C) Sclerotium rolfsii
D) Yeast
Answer: C) Sclerotium rolfsii
65. What is a characteristic of zoospores?
A) They are non-motile
B) They have flagella
C) They are produced in the air
D) They are produced in seeds
Answer: B) They have flagella
66. Which of the following fungi produces conidia?
A) Powdery mildew
B) Rhizoctonia
C) Pythium
D) Sclerotium rolfsii
Answer: A) Powdery mildew
67. What is the first step in fungal infection of plants?
A) Penetration through stomata
B) Germination of spores on the plant surface
C) Release of toxins
D) Formation of sclerotia
Answer: B) Germination of spores on the plant surface
68. Which of the following is an example of penetration through stomata?
A) Apple scab
B) Cedar apple rust
C) Root rots
D) Damping off
Answer: B) Cedar apple rust
69. What is the role of moisture in fungal infection?
A) It prevents infection
B) It accelerates spore germination
C) It cools the plant tissue
D) It disrupts fungal reproduction
Answer: B) It accelerates spore germination
70. What temperature range is most suitable for fungal reproduction?
A) 30°F to 50°F
B) 50°F to 70°F
C) 70°F to 90°F
D) 100°F to 120°F
Answer: C) 70°F to 90°F
71. How can plant diseases caused by fungi be spread?
A) By air currents and insects
B) By animals only
C) Only by human hands
D) By soil bacteria
Answer: A) By air currents and insects
72. What is a symptom of a fungal disease?
A) Mycelium
B) Yellowing of leaves (chlorosis)
C) Spore formation
D) Root galls
Answer: B) Yellowing of leaves (chlorosis)
73. What are conks?
A) Root galls caused by fungi
B) Fungal fruiting structures formed on rotting woody plants
C) Chemical substances produced by bacteria
D) Dead plant tissues due to viruses
Answer: B) Fungal fruiting structures formed on rotting woody plants
74. Which of the following symptoms refers to the yellowing of plant tissue?
A) Chlorosis
B) Blight
C) Mummy
D) Necrosis
Answer: A) Chlorosis
75. What is gummosis?
A) The formation of gall tumors in the plant
B) The production of gum in response to infection
C) A type of root rot caused by fungi
D) A sudden wilting of plant tissue
Answer: B) The production of gum in response to infection
76. What does the symptom ‘flagging’ refer to?
A) Death of roots
B) Death of the plant
C) Drooping of leaves and shoots before wilting
D) Yellowing of leaves
Answer: C) Drooping of leaves and shoots before wilting
77. What is the cause of root knot formation in plants?
A) Fungal infection
B) Bacterial invasion
C) Nematode feeding
D) Viral infection
Answer: C) Nematode feeding
78. Which nematode feeds primarily on plant roots?
A) Pine wilt nematode
B) Root-knot nematode
C) Cyst nematode
D) All of the above
Answer: D) All of the above
79. How do nematodes feed on plants?
A) By injecting a chemical substance into plant tissue and withdrawing plant material
B) By absorbing moisture from the leaves
C) By injecting viruses into the plant
D) By creating root galls
Answer: A) By injecting a chemical substance into plant tissue and withdrawing plant material
80. How are nematodes spread in the garden?
A) By wind
B) By rainwater
C) By transplants and soil
D) By insects
Answer: C) By transplants and soil
81. What is the role of insects in the spread of plant viruses?
A) They carry virus particles by sucking out plant material
B) They cause physical injury to the plant
C) They release spores
D) They transmit bacteria
Answer: A) They carry virus particles by sucking out plant material
82. Which method is NOT a way viruses are spread?
A) By insects
B) By mechanical transmission
C) By water evaporation
D) By infected seeds
Answer: C) By water evaporation
83. Which of the following is a symptom caused by viruses in plants?
A) Galls
B) Distorted fruit
C) Mycelium
D) Rot
Answer: B) Distorted fruit
84. What is the primary method of bacterial spread in plants?
A) Wind
B) Soil
C) Water
D) Insects and rain splashing
Answer: D) Insects and rain splashing
85. What does the symptom ‘mosaic’ refer to in plant diseases?
A) Mottling of leaves with green and yellow patches
B) Wilting of plants
C) Spots on fruit
D) Root decay
Answer: A) Mottling of leaves with green and yellow patches
86. What causes a “shot-hole” symptom in leaves?
A) Viral infection
B) Fungus infection causing holes after infected tissue falls off
C) Physical damage from insects
D) Excessive watering
Answer: B) Fungus infection causing holes after infected tissue falls off
87. What is a “scab” in plant disease?
A) A fungal structure on dead wood
B) A rough, crust-like area on plant surfaces
C) A type of virus-induced lesion
D) A bacterial ooze
Answer: B) A rough, crust-like area on plant surfaces
88. What is the cause of rust diseases in plants?
A) Bacteria
B) Fungi
C) Viruses
D) Nematodes
Answer: B) Fungi
89. What is a “mummy” in the context of plant diseases?
A) A dried, shriveled fruit
B) A fungal growth
C) A root knot
D) A bacterial mass
Answer: A) A dried, shriveled fruit
90. What is the primary role of root-knot nematodes in plant disease?
A) They cause root galls
B) They infect leaves
C) They spread bacterial infections
D) They produce fungal spores
Answer: A) They cause root galls
Plant Pathology MCQ E-Books Download91. What is “witches’ broom” in plant diseases?
A) A form of root rot
B) Broom-like growth caused by the clustering of branches
C) A bacterial infection on stems
D) A type of fungal spot on leaves
Answer: B) Broom-like growth caused by the clustering of branches
92. What type of diseases are classified as “yellows”?
A) Insect-induced diseases
B) Systemic mycoplasma-caused diseases
C) Fungal infections
D) Bacterial infections
Answer: B) Systemic mycoplasma-caused diseases
93. What is the ultimate goal of disease control in plants?
A) To remove all pathogens from the environment
B) To suppress the pathogen and manage the disease triangle
C) To cure the plant after disease symptoms appear
D) To destroy all affected plants
Answer: B) To suppress the pathogen and manage the disease triangle
94. What is a limitation of biological control for plant diseases?
A) It is always effective
B) It requires altering environmental conditions
C) It is time-consuming and may not always work
D) It cannot be applied to every plant species
Answer: C) It is time-consuming and may not always work
95. What is the key factor in successful disease control?
A) Complete elimination of the pathogen
B) Using a combination of control methods
C) Only applying chemical treatments
D) Planting the same crop every year
Answer: B) Using a combination of control methods
96. What does avoidance in disease control involve?
A) Using chemical fungicides
B) Changing the planting site or time to avoid disease
C) Removing infected plants after disease appearance
D) Installing wind barriers to stop disease spread
Answer: B) Changing the planting site or time to avoid disease
97. Which of the following is an example of disease exclusion?
A) Destroying infected plants
B) Using resistant plant varieties
C) Inspecting planting stock and rejecting diseased plants
D) Rotating crops regularly
Answer: C) Inspecting planting stock and rejecting diseased plants
98. When is eradication of a disease likely to be impossible?
A) Before the disease symptoms appear
B) After the disease has been established for a long time
C) When using chemical control methods
D) After planting resistant varieties
Answer: B) After the disease has been established for a long time
99. Which of the following is an example of a protection method in disease control?
A) Planting disease-free stock
B) Using fungicides or bactericides to prevent infection
C) Rotating crops to reduce pathogen buildup
D) Planting in non-susceptible areas
Answer: B) Using fungicides or bactericides to prevent infection
100. What does the term “resistance” in plant disease control refer to?
A) Complete immunity to diseases
B) The ability to withstand disease by natural or bred defenses
C) The total eradication of pathogens from the environment
D) The application of chemical control
Answer: B) The ability to withstand disease by natural or bred defenses
101. What is the main purpose of crop rotation in controlling soil-borne diseases?
A) To increase the nutrient content of the soil
B) To disrupt the life cycle of the pathogen
C) To provide better soil aeration
D) To protect plants from wind damage
Answer: B) To disrupt the life cycle of the pathogen
102. How can mulch help in controlling plant diseases?
A) By fertilizing the soil
B) By preventing pathogens from moving from soil to plants
C) By increasing humidity in the soil
D) By promoting plant growth
Answer: B) By preventing pathogens from moving from soil to plants
103. What role does deep plowing play in disease control?
A) It buries pathogens deep in the soil, preventing contact with plants
B) It fertilizes the soil
C) It creates better growing conditions for plants
D) It accelerates disease development
Answer: A) It buries pathogens deep in the soil, preventing contact with plants
104. What is sanitation in the context of plant disease control?
A) Applying chemicals to protect crops
B) Removing old leaves and stems to eliminate disease sources
C) Rotating crops to prevent soil pathogens
D) Using windbreaks to protect plants from diseases
Answer: B) Removing old leaves and stems to eliminate disease sources
105. How do certain plant disease organisms survive during the dormant stage?
A) By reproducing in healthy plant tissue
B) By remaining on dead or decaying plant material
C) By invading soil through wind
D) By infecting insects
Answer: B) By remaining on dead or decaying plant material
106. Which disease control method involves the removal of infected plant parts?
A) Eradication
B) Resistance
C) Protection
D) Therapy
Answer: D) Therapy
107. What is the effect of wind in the spread of plant diseases?
A) It does not play a role in disease spread
B) It spreads diseases over long distances
C) It eliminates pathogens from the garden
D) It enhances the growth of pathogens
Answer: B) It spreads diseases over long distances
108. What is the best way to control diseases disseminated by wind?
A) Regular spraying with chemicals to protect the foliage
B) Placing physical barriers to stop wind movement
C) Reducing watering during dry weather
D) Using insecticides to kill wind-borne insects
Answer: A) Regular spraying with chemicals to protect the foliage
109. Why is it recommended not to water the garden in the late afternoon?
A) To prevent water waste
B) To avoid increasing humidity
C) To keep the foliage dry overnight and reduce spore germination
D) To prevent plant roots from becoming too saturated
Answer: C) To keep the foliage dry overnight and reduce spore germination
110. What is one of the main challenges in controlling plant diseases?
A) High financial costs of disease control
B) Limited knowledge of pathogens and environmental conditions
C) Excessive use of chemical control methods
D) The need for immediate disease treatment
Answer: B) Limited knowledge of pathogens and environmental conditions
111. What is the primary reason gardeners should avoid saving seeds from their garden?
a) To prevent the spread of pathogens
b) To avoid pest infestation
c) To promote biodiversity
d) To enhance plant growth
112. What type of plant diseases are most commonly spread through seedborne pathogens?
a) Fungal diseases only
b) Bacterial diseases only
c) Both fungal and bacterial diseases
d) Viral diseases only
113. In plant pathology, what term refers to the parts of a pathogen capable of causing disease when brought near a host?
a) Mycelium
b) Inoculum
c) Pathogenetic structures
d) Spores
114. How long can Orobanche seeds survive in the soil?
a) 1 year
b) 5 years
c) 13 years
d) 30 years
115. Which of the following is NOT a method of pathogen survival during the off-season?
a) Survival in specialized resting structures
b) Survival as saprophytes
c) Survival in association with nematodes
d) Survival only as seeds
116. Which of the following is an example of a specialized resting structure of a pathogen?
a) Mycelium
b) Conidia
c) Germinating seeds
d) Bacterial cells
117. Which pathogen survives through the use of sclerotia, which can survive in a dry atmosphere?
a) Fusarium
b) Sclerotinia sclerotiorum
c) Pythium
d) Rhizoctonia solani
118. What is the survival mechanism of Rhizoctonia solani and Pythium debaryanum in the soil?
a) Saprophytic survival
b) Dormant spores
c) Symbiotic relationships with plants
d) Transmission via insects
119. What is the role of green manuring with grass in the control of potato scab?
a) It provides nutrients to the soil
b) It creates an environment that promotes pathogen survival
c) It antagonizes pathogens by promoting beneficial microbes
d) It encourages the growth of susceptible crops
120. How do soil inhabitants, like Rhizoctonia solani, survive in soil?
a) By forming resting spores
b) By living as saprophytes
c) By associating with nematodes
d) By infecting plant roots directly
121. Which of the following is NOT a type of pathogen that can survive as saprophytes in the soil?
a) Rhizoctonia solani
b) Erwinia carotovora
c) Agrobacterium
d) Sclerotinia sclerotiorum
122. In which of the following scenarios does a plant pathogen survive through vital association with living plants?
a) Through seed infection
b) By remaining dormant in the soil
c) By associating with beneficial microbes
d) Through the use of resting spores
123. Which pathogen causes the loose smut of wheat and survives as mycelium in the seed?
a) Ustilago nuda tritici
b) Colletotrichum lindemuthianum
c) Phytophthora infestans
d) Xanthomonas axonopodis
124. How do pathogens like Erwinia carotovora survive in the rhizosphere?
a) By forming resting spores
b) By multiplying in the soil
c) By creating a symbiotic relationship with plant roots
d) By acting as saprophytes in the rhizosphere
125. What pathogen survives in the rhizosphere of rice plants from germination to tillering stage?
a) Pseudomonas glumae
b) Burkholderia solanacearum
c) Clavibacter michiganensis
d) Agrobacterium
126. How do plant pathogenic bacteria typically survive the winter in infected seeds?
a) By producing spores
b) By infecting seed tissue directly
c) By forming dormant spores
d) By residing in the rhizosphere
127. What type of pathogen causes bacterial blight of cotton and survives in seeds?
a) Pseudomonas caryophylli
b) Xanthomonas axonopodis
c) Burkholderia solanacearum
d) Clavibacter michiganensis
128. How do pathogens like Clavibacter michiganensis subsp. michiganensis survive in tomato seeds?
a) As bacterial cells within the seed
b) As resting spores in the soil
c) As fungal mycelium within the seed
d) By forming symbiotic relationships with other pathogens
129. What pathogen causes the bacterial wilt of carnation and survives in planting material?
a) Clavibacter michiganensis
b) Pseudomonas caryophylli
c) Xanthomonas axonopodis
d) Agrobacterium tumefaciens
130. Which pathogen survives as mycelium in infected potato tubers, causing late blight?
a) Pseudomonas glumae
b) Phytophthora infestans
c) Burkholderia solanacearum
d) Xanthomonas axonopodis