TRB PG Assistant - Plant pathology - plant diseases due to fungi, bacteria and viruses, host–microbe interaction, principles of disease control - physical, chemical and biological methods Online Test (MCQ Quiz)

1. Which of the following is a characteristic symptom of powdery mildew on plants?

A) Water-soaked lesions on leaves B) Yellowing and stunting of the plant C) A white, powdery growth on the surface of leaves and stems D) Dark, sunken spots on fruits

2. Bacterial blight of rice, caused by *Xanthomonas oryzae pv. oryzae*, primarily affects which part of the plant?

A) Roots B) Flowers C) Leaves and leaf sheaths D) Grains

3. Which virus is responsible for the mosaic symptoms observed in tobacco plants, leading to significant crop loss?

A) Cucumber Mosaic Virus (CMV) B) Potato Virus Y (PVY) C) Tobacco Mosaic Virus (TMV) D) Barley Yellow Dwarf Virus (BYDV)

4. The interaction between a plant and a pathogen where the pathogen benefits and the plant is harmed is known as:

A) Symbiosis B) Mutualism C) Parasitism D) Commensalism

5. Which of the following is a physical method of plant disease control?

A) Application of fungicides B) Crop rotation C) Heat treatment of seeds D) Using resistant varieties

6. Rust diseases in plants are typically caused by fungi belonging to which class?

A) Oomycetes B) Ascomycetes C) Basidiomycetes D) Zygomycetes

7. Crown gall disease in plants, characterized by tumor-like growths, is caused by which bacterium?

A) Pseudomonas syringae B) Agrobacterium tumefaciens C) Erwinia amylovora D) Ralstonia solanacearum

8. The characteristic 'shoestring' appearance of infected plant parts, often seen in diseases like Dutch elm disease, is a symptom of vascular wilt caused by a fungus. Which fungus is primarily associated with Dutch elm disease?

A) Fusarium oxysporum B) Verticillium dahliae C) Ophiostoma ulmi D) Phytophthora infestans

9. Which term describes the ability of a plant to resist infection by a pathogen?

A) Virulence B) Pathogenicity C) Susceptibility D) Resistance

10. Crop rotation is a disease control strategy that primarily aims to reduce the buildup of which type of pathogen in the soil?

A) Airborne viruses B) Seed-borne bacteria C) Soil-borne fungi and bacteria D) Insects vectors

11. Late blight of potato, a devastating disease, is caused by an oomycete. What is its scientific name?

A) Albugo candida B) Plasmopara viticola C) Phytophthora infestans D) Peronospora destructor

12. Erwinia amylovora is the causal agent of which serious plant disease affecting pome fruits like apples and pears?

A) Bacterial spot B) Fire blight C) Black rot D) Scab

13. Which of the following is NOT a typical symptom of viral infection in plants?

A) Mosaic patterns B) Leaf curling or distortion C) Root rot D) Stunting or reduced growth

14. The process by which a pathogen establishes itself in a host plant and causes disease is called:

A) Sporulation B) Inoculation C) Infection D) Dissemination

15. A chemical method for controlling plant diseases involves the use of:

A) Sterilization of soil B) Application of pesticides C) Introduction of beneficial microbes D) Pruning infected branches

16. Smut diseases, characterized by the formation of black, powdery spore masses, are caused by fungi belonging to which order?

A) Ustilaginales B) Erysiphales C) Pucciniales D) Sphaeriales

17. Citrus greening, a destructive disease, is caused by a bacterium that lives and multiplies in the plant's phloem. What is the scientific name of this bacterium?

A) Liberibacter asiaticus B) Xylella fastidiosa C) Xanthomonas citri D) Pectobacterium carotovorum

18. Which virus causes leaf curl disease in tomato plants, leading to severely distorted and stunted growth?

A) Tobacco Streak Virus (TSV) B) Tomato Mosaic Virus (ToMV) C) Tomato Yellow Leaf Curl Virus (TYLCV) D) Cucumber Mosaic Virus (CMV)

19. The ability of a pathogen to cause disease is termed:

A) Inoculum potential B) Pathogenicity C) Virulence D) Aggressiveness

20. Biological control of plant diseases involves the use of:

A) Herbicides B) Antimicrobial agents C) Predators or parasites of the pathogen D) Soil fumigation

21. Anthracnose diseases, often causing sunken lesions on leaves, stems, and fruits, are typically caused by fungi belonging to which group?

A) Oomycetes B) Ascomycetes (especially Colletotrichum species) C) Basidiomycetes D) Zygomycetes

22. Blackleg of potato, a disease characterized by wilting and blackening of the stem base, is caused by which bacterium?

A) Rhizoctonia solani B) Streptomyces scabies C) Pectobacterium atrosepticum D) Ralstonia solanacearum

23. The movement of a pathogen or its spores from the source of infection to a new host plant is called:

A) Infection B) Inoculation C) Dissemination D) Pathogenesis

24. Which of the following is a method of seed treatment to control seed-borne diseases?

A) Foliar spray B) Soil drenching C) Chemical or hot water treatment D) Grafting

25. Mosaic symptoms, characterized by irregular patches of light and dark green or yellow on leaves, are most commonly associated with which type of pathogen?

A) Fungi B) Bacteria C) Viruses D) Nematodes

26. The process by which a pathogen penetrates the host plant is called:

A) Colonization B) Sporulation C) Penetration D) Reproduction

27. Which disease of cucurbits is caused by *Pseudomonas syringae pv. lachrymans* and manifests as small, angular, water-soaked spots on leaves that dry out and fall, creating a 'shot-hole' effect?

A) Powdery mildew B) Downy mildew C) Bacterial leaf spot D) Fusarium wilt

28. The use of genetically resistant plant varieties is a form of:

A) Chemical control B) Physical control C) Cultural control D) Genetic control

29. Which of the following fungi is a common cause of root rot and damping-off in seedlings?

A) Puccinia graminis B) Ustilago maydis C) Rhizoctonia solani D) Erysiphe graminis

30. Ring spot symptoms, often appearing as concentric rings on leaves or fruits, can be caused by various pathogens. Which pathogen is known to cause ring spot on Brassicas?

A) Albugo candida B) Peronospora parasitica C) Mycosphaerella brassicicola D) Xanthomonas campestris

31. The term 'virulence' in plant pathology refers to:

A) The presence of a pathogen on the plant surface B) The degree or intensity of pathogenicity C) The ability of a plant to resist disease D) The speed of pathogen reproduction

32. Which disease of wheat, caused by *Puccinia graminis f. sp. tritici*, is characterized by long, linear pustules on leaves and stems, often appearing reddish-brown?

A) Powdery mildew B) Stem rust C) Leaf rust D) Stripe rust

33. The yellow sticky traps used in fields are primarily for monitoring and controlling populations of:

A) Fungal spores B) Bacterial colonies C) Insect vectors of viruses D) Weed seeds

34. Which of the following is a method of sanitation for disease control?

A) Planting resistant varieties B) Removing and destroying infected plant debris C) Applying chemical sprays D) Using sterile soil

35. Aphanomyces euteiches is a notorious soil-borne oomycete that causes root rot in which group of crops?

A) Cereals B) Legumes C) Solanaceous crops D) Citrus

36. Which bacterium causes black rot of crucifers, characterized by V-shaped lesions on leaf margins and vascular discoloration?

A) Agrobacterium tumefaciens B) Pseudomonas syringae C) Xanthomonas campestris pv. campestris D) Erwinia carotovora

37. The process by which a plant recognizes and responds to a pathogen attack is part of:

A) Pathogen dissemination B) Host-pathogen interaction C) Spore germination D) Disease symptom development

38. Which of the following is a cultural practice for managing plant diseases?

A) Fungicide application B) Use of disease-free planting material C) Heat sterilization of tools D) Introduction of antagonistic microbes

39. The term 'inoculum' refers to:

A) The symptoms of a disease B) The pathogen itself or its propagules that initiate infection C) The resistance mechanism of the host plant D) The environment conducive to disease development

40. Which fungus causes the 'take-all' disease of cereals, affecting roots and stems, leading to stunted growth and whiteheads?

A) Fusarium culmorum B) Gaeumannomyces graminis C) Bipolaris sorokiniana D) Septoria tritici

41. Alternaria solani causes early blight in tomato and potato, characterized by target-spot lesions on leaves. This pathogen belongs to which group?

A) Oomycetes B) Basidiomycetes C) Ascomycetes D) Deuteromycetes (fungi imperfecti)

42. Which of the following is a common vector for plant viruses?

A) Earthworms B) Mites C) Aphids D) Springtails

43. The use of genetically modified crops with enhanced resistance is an example of:

A) Chemical control B) Biological control C) Cultural control D) Genetic control

44. A plant disease that is consistently present at low levels in a particular geographic area is described as:

A) Epidemic B) Epiphytic C) Endemic D) Pandemic

45. Which bacterial disease affects beans, causing water-soaked lesions on pods and leaves, often with bacterial ooze?

A) Angular leaf spot B) Halo blight C) Common bacterial blight D) Bacterial wilt

46. The term 'damping-off' refers to the sudden collapse and death of young seedlings, often caused by soil-borne pathogens like:

A) Puccinia spp. B) Xanthomonas spp. C) Phytophthora spp. and Pythium spp. D) Tobacco Mosaic Virus

47. Which of the following is a symptom of a vascular wilt disease?

A) Leaf spots B) Root galls C) Wilting and yellowing of foliage, often starting on one side of the plant D) Fruit rot

48. The use of heat to kill pathogens in soil or planting material is a form of:

A) Chemical control B) Biological control C) Physical control D) Cultural control

49. Which virus causes the 'leaf roll' disease in potato, leading to upward rolling of leaves and stunted growth?

A) Potato Virus X (PVX) B) Potato Virus Y (PVY) C) Potato Leafroll Virus (PLRV) D) Tobacco Etch Virus (TEV)

50. The study of plant diseases, their causes, development, and control is known as:

A) Horticulture B) Agronomy C) Plant Pathology D) Entomology

Plant pathology - plant diseases due to fungi, bacteria and viruses, host–microbe interaction, principles of disease control - physical, chemical and biological methods - Online Test

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