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

Which of the following diseases are caused by fungal pathogens only in barley? P. Kernel blight Q. Anthracnose R. Dwarf bunt S. Leaf rust T. Basal glume rot

  1. P and Q

  2. Q and R

  3. R and S

  4. P, R, T

  5. Q, R, S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In apple, Kernel blight disease is caused by bacteria- Pseudomonas syringae pv. syringae and Basal glume rot is caused by bacteria- Pseudomonas syringae pv. atrofaciens. Anthracnose, Dwarf bunt and Leaf rust are caused by fungal pathogens- Collectotrichum cereale, Tilletia controversa and Puccinia hordei respectively, in apple.

Multiple choice

‘Marsonia blotch’ disease of apple is caused by fungal species. Which of the following is/are the correct ones? P. Diplocarpon mali Q. Marsonia coronaria R. Mucor piriformis S. Nectria galligena

  1. P and Q

  2. Q and R

  3. R and S

  4. P, Q, R

  5. Q, R, S
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In apple, Diplocarpon mali and Marsonia coronaria cause ‘Marsonia blotch’ disease, Mucor piriformis causes the Mucor rot disease and Nectria galligena causes Canker disease.

Multiple choice

Which of the following statement(s) is/are true? P. Spot anthracnose disease of rose is caused by Sphaceloma rosarum. Q. Bordeaux mixture was introduced by Pierre-Marie-Alexis Millardet in 1885. R. Plant pathogenic disorders can be controlled by crop rotation.

  1. Only P

  2. Only Q

  3. R only

  4. All of these

  5. None of these
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

In rose, Spot anthracnose disease is caused by the fungus- Sphaceloma rosarum. In the 19th century, several outbreaks of vine diseases occurred among the Vitis vinifera vines of the classicial European wine regions. After the downy mildew had struck, botany professor Pierre-Marie-Alexis Millardet of the University of Bordeaux studied the disease in vineyards of the Bordeaux region. In1885, Millardet published your findings on mildew of grapes and introduced Bordeaux mixture to control downy mildew of grapes. Crop rotation may be an effective means to prevent a parasitic population from becoming well-established, as an organism affecting leaves would be starved when the leafy crop is replaced by a tuberous type, etc. Other means to undermine parasites without attacking them directly may exist.

Multiple choice

Which of the following statement(s) is/are false? P. Bunchy top disease of banana is caused by Pyricularia grisea. Q. Pseudomonas solanacearum causes Pseudostem heart rot disease in banana. R. Rhizome rot disease of banana is caused by Erwinia carotovora.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

  5. Q and R
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

P. Bunchy top disease of banana is caused by Banana bunchy top virus (BBTV). Pyricularia grisea fungus causes Pitting disease in banana. Q. Pseudostem heart rot disease of banana is caused by Fusarium moniliforme. Pseudomonas solanacearum causes Bugtok disease in banana. R. Rhizome rot disease of banana is caused by Erwinia sp. like- E. carotovora, E. chrysanthemi. Hence, P and Q both the statements are false.

Multiple choice

Match the diseases in apple( List - A) with causing fungal pathogens (List - B) and select the correct answer using the codes given below the lists ||| |---|---| |List - A|List - B| |A. Perennial canker|1. Grovesinia pyramidalis| |B. Fruit decay|2. Neofabraea perennans| |C. Pink mold rot|3. Trichothecius roseum| |D. Zonate leaf spot|4. Valsa ceratosperma| | |5. Phomopsis mali|

  1. A - 2, B - 4, C - 3, D - 5

  2. A - 1, B - 2, C - 3, D - 1

  3. A - 2, B - 5, C - 3, D - 1

  4. A - 4, B - 5, C - 1, D - 2

  5. A - 1, B - 2, C - 5, D - 4
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

In apple, Perennia canker disease is caused by Neofabraea perennans, Fruit decay is caused by Phomopsis mali, Pink mold rot disease is caused by Trichothecius roseum and Zonate leaf spot disease is caused by Grovesinia pyramidalis. Hence, the correct sequence of codes A-2, B-5, C-3, D-1 is correct.

Multiple choice

Match the rice diseases in Group-I with the causing pathogens in Group-II ||| |---|---| |Group-I|Group-II| |P. Black kernel|1. Alternaria padwickii| |Q. Leaf smut|2. Curvularia lunata| |R. Stackburn|3. Sclerophthora macrospora| |S. Downy mildew|4. Entyloma oryzae|

  1. P - 2, Q - 4, R - 1, S - 3

  2. P - 2, Q - 1, R - 4, S - 3

  3. P - 3, Q - 4, R - 1, S - 2

  4. P - 4, Q - 1, R - 2, S - 3

  5. P - 3, Q - 4, R - 2, S - 1
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In rice, the fungus curvularia lunata causes black kernel. Leaf smut disease is caused by Entyloma oryzae, Stackburn disease is caused by Alternaria padwickii and Downy mildew disease is caused by Sclerophthora macrospora. Hence, the correct answer using the codes is P-2, Q-4, R-1, S-3.

Multiple choice

Which of the following Xanthomonas campestris cause(s) the disease(s) in Citrus?

  1. Bacterial spot
  2. Black pit
  3. Blast
  4. Canker

  1. Only 1

  2. Only 2

  3. Only 3

  4. 2 and 3

  5. 1 and 4
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In citrus, bacterial spot and canker disease are both caused by the bacteria Xanthomonas campestris. Both the black pit and blast diseases in citrus are caused by the bacteria Pseudomonas syringae. Hence, 1 and 4 both are caused by Xanthomonas campestris in citrus.

Multiple choice

Rhizopus stolonifer belongs to:

  1. Ascomycetes

  2. Deuteromycetes

  3. Zygomycetes

  4. Oomycetes

  5. Myxomycetes
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

It belongs to Zygomycetes as it synthesizes chitosan where other fungi have chitin as structural polysachharide. Chitosan is deacetylated homopolymer of chitin.