Biology

Microbes and Plant Diseases

1,145 Questions

Microbes and plant diseases examine the role of fungi, bacteria, and viruses in causing infections in plants and humans. Topics cover symbiotic associations like mycorrhiza, fungal structures, and specific agricultural pathogens. Practice these biology questions to master microbiology concepts for upcoming competitive examinations.

Fungal associationsPlant pathogensMicrobial structuresBacterial infections

Microbes and Plant Diseases Questions

Multiple choice

The leaf blight on carrot is caused by

  1. Alternaria triticina

  2. Alternaria solani

  3. Alternaria panax

  4. Alternaria carotiincultae
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Alternaria carotiincultae is a plant pathogen & causes leaf blight on carrot.

Multiple choice

The fungus with bioluminescent characteristic is

  1. Claviceps purpurea

  2. Omphalotus olearius

  3. Cordyceps sinensis

  4. Trametes versicolor
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

This fungus is distinguished by its bioluminescent characteristic. Ingestion of even small amounts of this highly toxic fungus can lead to severe diarrhea, vomiting and cramps.

Multiple choice

Which of the following is not a correct match?

  1. Root knot disease – Nematode Heterodera marioni

  2. Smut of bajra – Helminthosporium sacchari

  3. Covered smut of barley – Ustilago nuda

  4. Late blight of potato – Phytophthora infestans
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Covered smut of barley is caused by Ustilago hordei.

Multiple choice

'Watermelon snow' is caused due to

  1. Trichodesmium

  2. Gonyulaux

  3. Chlamydomonas nivalis

  4. Red algae
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It causes 'Red snow'. Its hypnospores consist of a red colour pigment, which gives the colour to snow.

Multiple choice

Which one of the following organisms is a fungus?

  1. Staphylococcus

  2. Salmonella

  3. Clostridium

  4. Aspergillus
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Aspergillus is a genus of fungi, while the other three options are all bacteria. Staphylococcus and Clostridium are genera of bacteria, and Salmonella is a bacterial genus as well.

Multiple choice

The predominant disease of groundnut is

  1. pad rot

  2. leaf blight

  3. leaf spot (tikka)

  4. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Leaf spot (tikka disease) caused by Cercospora arachidicola is the most widespread and economically important disease of groundnut, affecting both yield and quality. Pad rot occurs but is less common, while leaf blight is not a major groundnut disease.

Multiple choice

Appearance of dry, scaly lesions on various parts of the body such as skin, nails and scalp are the main symptoms of fungal disease. These lesions are accompanied by intense itching and irritation. Identify the disease.

  1. Aspergillosis

  2. Dandruff

  3. Scabies

  4. Ring worm

  5. Amoebiasis
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Appearance of dry, scaly lesions on various parts of the body such as skin, nails and scalp are the main symptoms of a fungal disease. These lesions are accompanied by intense itching and irritation. 

Multiple choice

Which of the following statements is/are not correct?

  1. Leaf streak disease of maize is caused by Stenocarpella macrospora.
  2. Stem rot of potato is caused by Sclerotium rolfsii.
  3. Athelia arachnoidea causes crater rot in carrot.
  4. Cercospora brachypus causes noble rot disease in grapes.

  1. Only 1

  2. 1 and 2

  3. 2 and 3

  4. 3 and 4

  5. Only 4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Correct answer. Grey rot or Noble rot disease is caused by Botrytis cinerea in grapes. Mycosphaerella angulata and Cercospora brachypus cause angular leaf spot in grapes. Hence, the statement 4 is false.

Multiple choice

Which of the following is the causative fungal agent for ‘Halo spot’ disease in barley?

  1. Pyrenophora teres f. teres

  2. Rhynchosporium secalis

  3. Blumeria graminis f. sp. hordei

  4. Puccinia hordei

  5. Pseudoseptoria stomaticola
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In barley, white to tan, small and semi-rectangular spot or blotch with a dark brown edge aligned along the veins of the leaf blade is known as Halo spot disease. The causative fungus of the said disease is Pseudoseptoria stomaticola.

Multiple choice

Identify the false statement(s).

A. Tropical cotton rust of cotton is caused by Phakopsora gossypii. B. Puccinia striiformis causes scald disease in barley. C. The causative agent for cottony snow mold of wheat is Tilletia controversa.

  1. Only A

  2. Only B

  3. Only C

  4. A and B

  5. B and C
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

The causative fungal agent for stripe yellow rust of barley is Puccinia striiformis. Scald disease of barley is caused by the fungus Rhynchosporium secalis. Cottony snow mold disease of wheat is caused by the fungus Coprinus psychromorbidus. Dwarf bunt of wheat is caused by Tilletia controversa. Hence, the statements B and C both are false.