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 evs - i food for all improved methods of agriculture receding water table water conservation and irrigation

When a natural predator (living organism) is applied on the other pathogen organisms to control them, this process is called as:

  1. Biological control

  2. Genetic engineering

  3. Artificial control

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

Indiscriminate eradication of pests is undesirable because without them the beneficial predatory and parasitic organisms which depend upon them for food would also be eliminated. The biocontrol method of pest and pathogen control involves use of viruses, bacteria and other insects (which are their natural predators and pests).

Multiple choice plant diseases keeping diseases away biology

Pusa Swarnim a variety of Brassica is resistant to

  1. Bacterial blight

  2. White rust

  3. Curl and black rot

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

Pusa Swarnim is a biofortified and disease-resistant variety of Brassica (mustard) specifically developed for resistance against White rust.

Multiple choice plant diseases keeping diseases away biology

Plants protect themselves from fungi by producing.

  1. Protoxins

  2. Phytoalexins

  3. Prolectins

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

Protoxins-precursor of toxins.

Phytoalexins-a substance produced by plant tissues in response to contact with parasite.
Prolectins-precursor of plant lectins.
All the above can be used by plants for protection from fungi.
Correct answer-D

Multiple choice plant diseases keeping diseases away biology

Which of the following is a bacterial plant disease

  1. Tikka disease of Groundnut

  2. Downy mildew of Grapes

  3. Ring rot of Potato

  4. Red rot of Sugarcane.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Ring rot of potato is caused by the bacterium Clavibacter michiganensis subsp. sepedonicus. The other options listed are fungal diseases.

Multiple choice plant diseases keeping diseases away biology

Symptoms of red rot disease appear over :

  1. Leaf tip

  2. Whole leaf

  3. Mid rib

  4. Leaf margin
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation
The red rot of sugar cane is caused by a fungus glomurella tucumensis. Infected canes, either singly or in clumps, show a sudden orange to yellow discoloration and later the leaves gradually dry. Symptoms include Brown or reddish brown stripes appear externally at nodal region, minute red spots on the upper surface of the midrib in both the directions.

So, the correct answer is 'Mid rib'.
Multiple choice plant diseases keeping diseases away biology

Pusa Komal variety of Cow Pea Is resistant to disease

  1. White rust

  2. Leaf curl

  3. Bacterial blight

  4. Hill bunt.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Pusa Komal is a well-known variety of cowpea bred for resistance to bacterial blight.

Multiple choice plant diseases keeping diseases away biology

An Albugo caused disease in which pustules on the surface of leaves, stem inflorescence and floral parts along with various type of deformities of which, hypertrophy is most pronounced, are the characteristic symptoms of ___________________.

  1. Yellow stripe rust of wheat

  2. White rust of mustard

  3. Yellow ear rot and ear cockle of wheat

  4. Udbatta disease of rice
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

White rust of mustard is caused by the oomycete Albugo candida, characterized by white blister-like pustules and pronounced hypertrophy and deformation of infected plant parts.

Multiple choice plant diseases keeping diseases away biology

Which one of the following statements is not correct?

  1. The bunt of rice is found only in southern India

  2. The pathogen of the stem rot of rice belongs to Deuteromycetes.

  3. The blast disease of rice affects the crop in all stages

  4. In the brown spot disease of rice all parts of the plant are infected exept roots.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The bunt of rice is not restricted to southern India; it is found in various rice-growing regions. The other statements are generally accepted facts in plant pathology.

Multiple choice plant diseases keeping diseases away biology

Which one of the following types of organisms causes the disease Potato Witches broom?

  1. Virus

  2. Mycoplasma

  3. Fungus

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

Potato Witches broom is a phytoplasmal disease (caused by phytoplasma, formerly grouped under Mycoplasma-like organisms) characterized by excessive proliferation of shoots.

Multiple choice plant diseases keeping diseases away biology

The foul fishy smell of a volatile chemical trimethylamine in the disease infested wheat field is an indicator of ____________.

  1. Rust

  2. Smut

  3. Blast

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

Bunt of wheat, caused by Tilletia species, produces teliospores that release trimethylamine, giving off a characteristic foul fishy odor in infested fields.

Multiple choice plant diseases keeping diseases away biology

Which one of the following complexes is responsible for the cause of Tundu disease in wheat?

  1. Fungus-nematode

  2. Nematode-bacterium

  3. Fungus-bacterium

  4. Virus-fungus
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Tundu disease of wheat is a composite disease caused by a combination of the seed gall nematode (Anguina tritici) and the bacterium (Clavibacter tritici) working together as a disease complex.

Multiple choice plant diseases keeping diseases away biology

Consider the following:
1. Bacillus subtilis                 2. Trichadiama viride
3. erysiphe graminis             4. Septoria glycines
Which of the above antagonistic orgaanisms is /are capable of suppressing plant disease?

  1. 1 and 2

  2. 2 and 3

  3. 2, 3 and 4

  4. 1 only
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Bacillus subtilis and Trichoderma viride are well-documented biological control agents used to suppress various plant pathogens.

Multiple choice plant diseases keeping diseases away biology

The toxic substance produced by the pathogen causing Brown leaf spot of rice, harming seedlings reducing respiration of the host is?

  1. Piricularian

  2. A-Picolinic acid

  3. Cochliobolin

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

Consider the following diseases of plants.
a. Root knot of sugar-cane.
b. Root rot of wheat.
c. Wilt of cotton.
d. Angular leaf spot of cotton.
Which of these diseases is/are caused by fungi?

  1. $1$ and $4$ only
  2. $2$ only
  3. $2$ and $3$
  4. $1, 3$ and $4$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Root rot of wheat is caused by fungal pathogens such as Fusarium or Rhizoctonia species, and wilt of cotton is caused by the fungus Fusarium oxysporum. Root knot of sugar-cane is typically nematode-induced, and angular leaf spot of cotton is bacterial.

Multiple choice plant diseases keeping diseases away biology

Which one of the following diseases of rice is not caused by microbe?

  1. Tip burn of paddy

  2. Stem rot of paddy

  3. False smut of paddy

  4. Blast disease of rise
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tip burn of paddy is a physiological disorder caused by environmental factors like high temperature or water stress, not by a living microbe. In contrast, stem rot, false smut, and blast are all caused by fungal pathogens.