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 plant diseases keeping diseases away biology

The major effect of crown gall pathogen on its hosts is the ______________.

  1. Yellowing of leaves and stem

  2. Stunted growth

  3. Hyperplasia and hypertrophy

  4. Matting or foots with small tubercles
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant diseases keeping diseases away biology

Which one of the following antagonists has been commercialized for the biological control of plants diseases?

  1. Peniophora gigantea

  2. Streptomyces rochii

  3. Bacillus subtilis

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

Peniophora gigantea (now Phlebiopsis gigantea) was one of the first fungi to be successfully commercialized for the biological control of root rot in conifers.

Multiple choice plant diseases keeping diseases away biology

Consider the following organisms.
a. Viruses
b. Bacteria
c. Mycoplasmas
d. Fungi
The correct chronological sequence in which they were, recognized as incidents of plant diseases is?

  1. $1, 2, 3, 4$
  2. $4, 2, 1, 3$
  3. $4, 1, 3, 2$
  4. $1, 4, 2, 3$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant diseases keeping diseases away biology

Which one of the following pairs is NOT correctly matched?

  1. Wart disease - Synchytrium of potato endobioticum

  2. Soft rot of- Phtomonas ricinii of wheat ears

  3. Bacterial rot- Phytomonas ricinii of wheat ears

  4. Late blight- Phytophthora infections of potato
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant diseases keeping diseases away biology

Which one of the following diseases is caused by mycoplasma-like organism?

  1. Sugarcane mosaic disease

  2. Wilt disease of sugarcane

  3. Ring spot of sugarcane

  4. Grassy shoot of sugarcane
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant diseases keeping diseases away biology

Which of the following is not a viral disease of plants?

  1. Red rot of sugarcane

  2. Tobacco mosaic disease

  3. Leaf curl of tomato

  4. Tristeza disease of citrus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Red decay is the most widely recognized infection of sugarcane, caused by the growth Colletotrichum falcatum Went. 

So, the correct option is 'Red rot of sugarcane'.

Multiple choice plant diseases keeping diseases away biology

Which one of the following fungi has been found useful in the biological control of plant diseases?

  1. Penicillium notatum

  2. Phytophthora parasitica

  3. Trichoderma viride

  4. Mucor mucedo
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant diseases keeping diseases away biology

A wheat plant is infected by the aecidiospores of black stem rust fungus produced on the alternate host. What is the correct sequence of the following stages in the disease cycle?
a. Uredo stage
b. Pycnidial stage
c. Basidial stage
d. Teleuto stage
e. Aecidial stage
Select the correct answer using the codes given.

  1. $1, 4, 3, 5, 2$
  2. $1, 3, 4, 5, 2$
  3. $1, 2, 3, 4, 5$
  4. $1, 4, 3, 2, 5$
Reveal answer Fill a bubble to check yourself
A Correct answer
Multiple choice plant diseases keeping diseases away biology

Biological control of some soil-borne plant diseases has been achieved through the use of __________.

  1. Rhizobacteria

  2. Streptomyces

  3. Nostoc

  4. Micrococcus
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Plant Growth-Promoting Rhizobacteria (PGPR) are extensively used for the biological control of soil-borne plant diseases.

Multiple choice plant diseases keeping diseases away biology

Which one of the following is a causal agent of wart disease of potato?

  1. Synchytrium and endobioticum

  2. Plasmodiophora brassicae

  3. Spongospora subterranea

  4. Pseudomonas solanacearum
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Wart disease of potato is caused by Synchytrium endobioticum, a chytrid fungus. The correct scientific name should be written as two words: Synchytrium endobioticum. This pathogen causes tumor-like galls (warts) on potato tubers and is a quarantine disease in many regions. Plasmodiophora brassicae causes club root of crucifers, Spongospora subterranea causes powdery scab of potato, and Pseudomonas solanacearum causes bacterial wilt.

Multiple choice plant diseases keeping diseases away biology

Turnip mosaic disease is caused by

  1. Bacteria

  2. Viruses

  3. Nematodes

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

Turnip Mosaic Disease is caused by the Turnip Mosaic Virus (TuMV), a potyvirus belonging to family potyviridae, that infects majority of plants belonging to Cruciferae or Brasscicaceae. They virus can be transmitted through vectors - Aphids.

So, the correct answer is 'Viruses'

Multiple choice plant diseases keeping diseases away biology

Pyricularia oryzae causes

  1. Citrus canker

  2. Blast disease of rice

  3. Tungro disease of rice

  4. Tikka disease of groundnut
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Pyricularia oryzae is a fungus that causes rice blast that results in lesions on leaves, stems, peduncles, panicles, seeds, and even roots. 

A. Citrus canker is caused by the bacterium Xanthomonas axonopodis. 
B. Blast disease of rice is caused by Pyricularia oryzae.
C. Tungro disease of rice is caused by the virus pararetrovirus of the family Caulimoviridae.
D. Tikka disease of groundnut is caused by the Cercospora personata.
Hence, the correct answer is 'Blast disease of rice'

Multiple choice plant diseases keeping diseases away biology

Which of the following is not a fungal disease?

  1. Red rot of sugarcane

  2. Wilt of arhar

  3. Brown leaf spot of rice

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

Potatoes may be infected with many different viruses that can reduce tuber quality and yield. Mosaic virus of potatoes is one such disease that actually has multiple strains. Potato mosaic virus is divided into three categories. Symptoms of the different mosaic virus of potatoes may be similar, so the actual type usually can’t be identified by symptoms alone and is often just referred to as mosaic virus in potatoes. The three types of recognized mosaic virus in potatoes are Latent (Potato virus X), Mild (Potato virus A), Rugose or Common mosaic (Potato virus Y).

So the correct option is 'potato mosaic'.


Multiple choice botany living world mycorrhiza classification of fungi kingdom monera, protista and fungi useful and harmful microbes

Mycorrhiza is the

  1. Symbiotic association between fungus and roots of seed plants.

  2. Parasitic association between fungus and the roots of seed plants.

  3. Saprophytic association between fungus and roots of seed plants.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mycorrhiza refers to the symbiotic association of a fungus and roots of vascular plants. During this association, the fungus colonizes on the roots of the host seed plants either intracellularly or extracellulary and is generally mutualistic rather than pathogenic.

Thus, the correct answer is option A.