Biology

Microbes and Plant Diseases

1,118 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 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.

Multiple choice

Which of the following fungi is heteroecious?

  1. Puccinia

  2. Ustilago

  3. Rhizopus

  4. Yeast

  5. Mucor
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

It is a heteroceous fungi genus that needs two host, one is primary and another secondary. Both the primary host and an alternate unrelated host are required for the parasite to complete the life cycle.

Multiple choice

Which of the following units is used to measure bacterial growth?

Bacterial growth is the division of one bacterium into two daughter cells in a process called binary fission.

  1. IU/L

  2. mM fraction

  3. O.D

  4. cfu/ml

  5. cell/colony
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

O.D, i. e., optical density. In spectroscopy, the absorbance, i.e., optical density of a material is a logarithmic ratio of the radiation falling upon a material to the radiation transmitted through a material. Measurements of absorbance are carried out in analytical chemistry. This measures the rate of growth of a bacterial culture.

Multiple choice

Match the following:

a. Stachybotrys atra 1. Indoor mold
b. Aspergillus niger 2. Textile
c. Bipolaris 3. Black mold
d. Ulocladium 4. Food decaying

  1. a - 3, b - 4, c - 1, d - 2

  2. a - 4, b - 3, c - 2, d - 1

  3. a - 3, b - 1, c - 4, d - 2

  4. a - 1 , b - 4, c - 3, d - 2

  5. a - 2, b - 3, c - 4, d - 1
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Stachybotrys atra is a black mold, Aspergillus niger is an indoor mold, Bipolaris decays foods, and Ulocladium is related to textiles.

Multiple choice

Which of the following fungi is used in production of antibiotics?

In our daily routine, fungi have both positive and negative impacts. There are number of beneficial roles of fungi in different aspects of our life such as food, scientific uses, medicines, agriculture, commercial products, etc.

  1. S. cerevisae

  2. Mycorrhiza

  3. Streptomycin

  4. Mushrooms

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

Streptomycin is used in production of antibiotic drugs,  which can not be taken orally. It must be used as intracellular injection on a regular basis.