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

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.

Multiple choice

The causative pathogen(s) for ‘Sooty blotch’ of apple is/are A. Peltaster fructicola B. Leptodontidium elatius C. Chondrostereum purpureum D. Helicobasidium mompa

  1. Only A

  2. Both A and B

  3. Both B and C

  4. Both C and D

  5. Only D
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Sooty blotch colonies appear dusty to olive green or black on mature fruit depending on the particular fungus species involved. Sooty blotch causing fungal pathogens are- Peltaster fructicola, Geastrumia polystigmatis, Leptodontidium elatius, Gloeodes pomigena. Silver leaf disease is caused by Chondrostereum purpureum in apple. Violet root rot is caused by Helicobasidium mompa.

Multiple choice

Match the Almond diseases in List - A with causing fungal pathogens in List - B.

 
List - A
List - B
A. Armillaria root rot 1. Venturia carpophila
B. Green fruit rot 2. Rhizomorpha subcorticalis
C. Hull rot 3. Rhizopus sp
D. Scab

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

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

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

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

  5. A - 2, B - 1, C - 3, D - 4
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Armillaria root rot is caused by the fungi- Armillaria mellea and Rhizomorpha subcorticalis in Almond. Green fruit rot disease of Almond is caused by Botrytis cinerea, Botryotinia fuckeliana and Monilinia fructicola. Hull rot disease of Almond is mainly caused by Rhizopus sp.Venturia carpophila and Cladosporium carpophilum cause Scab disease of Almond. Hence, the sequence of codes A-2, B-4, C-3, D-1 is correct.