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

What is the mode of nutrition in mushroom?

  1. Autotrophic

  2. Symbiotic

  3. Saprophytic

  4. Parasitic

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Mushrooms are fungi, and fungi have a saprophytic mode of nutrition. Saprophytes obtain nutrients by absorbing dissolved organic matter from dead and decaying organisms. They secrete digestive enzymes into their environment and then absorb the broken-down nutrients. Unlike autotrophs (plants, some bacteria) that produce their own food, or parasites that obtain nutrients from living hosts, mushrooms (fungi) are decomposers that feed on dead organic matter.

Multiple choice

Which of the following statement(s) is/are false regarding ‘African daisy plant’? P. Downy mildew disease is caused by Cercospora gerberae. Q. Nectria canker disease is caused by Erysiphe cichoracearum. R. Sclerotium rolfsii causes ‘Southern blight’ disease.

  1. Only P

  2. Only Q

  3. Only R

  4. Both P and Q

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

Downy mildew disease of African daisy plant is caused by fungus- Plasmopara majewskii.
Cercospora gerberae causes Cercospora leaf spot disease in African daisy plant. Nectria canker disease is caused by Haematonectria haematococca fungus in African daisy plant. Powdery mildew is caused by the fungal pathogen Erysiphe cichoracearum in African daisy plant. Southern blight disease is caused by Sclerotium rolfsii in African daisy plant. Hence, P and Q both are false statements.

Multiple choice

Which of the following statements is/are not true about fungal diseases of coffee? P. Red blister disease of coffee is caused by Fusarium solani. Q. Phoma costaricensis causes thread blight disease. R. Gibberella xylarioides causes tracheomycosis.

  1. Only P

  2. Only Q

  3. Only R

  4. Both P and Q

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

Red blister disease of coffee is caused by Cercospora coffeicola. Dry root rot disease of coffee is caused by Fusarium solani. Thread blight disease is caused by Corticium koleroga in coffee. Phoma costaricensis causes tip blast disease in coffee. Tracheomycosis is caused by the fungus Gibberella xylarioides in coffee.

Multiple choice

The fungus(fungi) responsible for ‘Loose smut’ of barley is/are A. Ustilago tritici B. Ustilago segetum C. Pyrenophora wirreganensis

  1. Only A

  2. Only B

  3. Only C

  4. Both A and B

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

Infected heads emerge as a mass of dark brown powdery spores is called loose smut. A fungus, Ustilago tritici, causes loose smut disease in barley. Covered smut is caused by the fungus Ustilago segetum var. hordei in which the heads that emerge are dark in colour and smut balls take the place of the grain. Wirrega blotch of leaf is caused by the fungus Pyrenophora wirreganensis.

Multiple choice

Which of the following pair of ‘cotton diseases: causative fungi’ is not correctly matched?

  1. Black root rot: Ramularia gossypii

  2. Anthracnose: Colletotrichum gossypii

  3. Lint contamination: Aspergillus flavus

  4. Powdery mildew: Oidiopsis gossypii

  5. Stem canker: Phoma exigua
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Black root rot of cotton is caused by Thielaviopsis basicola and Chalara elegans. Ramularia gossypii causes aereolate mildew disease of cotton.

Multiple choice

Which of the following statement(s) is /are false? A. Coprinus psychromorbidus causes cottony snow mold in wheat. B. Black shoulder disease of tomato is caused by Chalara elegans. C. Tropical cotton rust of cotton is caused by Puccinia cacabata.

  1. Only A

  2. Only B

  3. Only C

  4. Both A and B

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

Cottony snow mold disease of wheat is caused by the fungus Coprinus psychromorbidus. Black shoulder disease of tomato is caused by Alternaria alternate. Chalara elegans causes Black root rot of tomato.Tropical cotton rust of cotton is caused by Phakopsora gossypii. Puccinia cacabata causes Southwestern cotton rust in cotton.

Multiple choice

Which of the following statements are true? P. Diplocarpon mali and Marsonia coronaria cause ‘Marsonia blotch’ disease in apple. Q. Bird's-eye rot disease in grapes is caused by Cercospora brachypus. R. Chocolate spot disease of Papaya is caused by Calonectria crotalariae. S. Cladosporium sp. and Fusarium sp. both are causing pathogens for Internal blight of papaya.

  1. Both P and Q

  2. Both Q and R

  3. Both R and S

  4. Both Q and S

  5. Both P and S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In apple, Diplocarpon mali and Marsonia coronaria cause ‘Marsonia blotch’ disease. Bird's-eye rot disease in grapes is caused by Elsinoe ampelina and Sphaceloma ampelinum. Cercospora brachypus causes Angular leaf spot disease in grapes. Chocolate spot disease is caused by Colletotrichum gloeosporioides in papaya. Cylindrocladium crotalariae and Calonectria crotalariae cause Collar rot disease in papaya. Internal blight of papaya is caused by Cladosporium sp., Fusarium sp. and Penicillium sp.

Multiple choice

Match the diseases of fruit crops in Group - I with fungal pathogens in Group - II.

 
Group - I
Group - II
P. Leaf spot of cherries and palms 1. Cerecosoridium viticola
Q. Brown leaf spot of grapes 2. Taphrina deformans
R. Citrus greasy leaf spot 3. Blueriella sp.
S. Leaf curl of peach and apricot 4. Mycosphaerella musicosa
5. Mycosphaerella citri

  1. P - 3, Q - 1, R - 5, S - 2

  2. P - 5, Q - 1, R - 4, S - 2

  3. P - 3, Q - 4, R - 5, S - 2

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

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

Leaf spot of cherries and palms is caused by Blueriella sp. Brown leaf spot of grapes is caused by Cerecosoridium viticola. Citrus greasy leaf spot is caused by the fungus Mycosphaerella citri. Banana leaf spot is caused by Mycosphaerella musicosa. Taphrina deformans causes leaf curl of peach and apricot. Hence, the correct sequence of codes is P-3, Q-1, R-5, S-2.