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

Which of the following pairs is incorrectly matched?

  1. Whisker mold - Penicillium ulaiense

  2. Mal secco - Phoma tracheiphila

  3. Blue mold - Penicillium italicum

  4. Green fruit mold - Mucor paronychia

  5. Rootlet rot - Pythium rostratum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Penicillium digitatum causes Green fruit mold in citrus. Mucor fruit rot is caused by Mucor sp. (Mucor paronychia, Mucor racemosus).

Multiple choice

Match the following:

 
Group - I Group - II
P. Leaf spot of cherries and palms 1. Claviceps purpurea
Q. Ergot of barley 2. Taphrina deformans
R. Citrus greasy leaf spot 3. Blueriella sp.
S. Leaf curl of peach and apricot 4. Drechslera teres
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. The causative agent for ergot disease in Barley is Claviceps purpurea. Citrus greasy leaf spot is caused by the fungus Mycosphaerella citri. Banana leaf spot is caused by Mycosphaerella musicosa.

Multiple choice

The causative fungal agent for ‘Halo spot’ disease in barley is

  1. Pyrenophora teres f. teres

  2. Rhynchosporium secalis

  3. Blumeria graminis f. sp. hordei

  4. Puccinia hordei

  5. Pseudoseptoria stomaticola
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

In Barley, white to tan, small, semi-rectangular spots or blotches with a dark brown edge aligned along the veins of the leaf blade is known as Halo spot disease. The causative fungus of the said disease is Pseudoseptoria stomaticola.

Multiple choice

Which of the following statements is/are false?

P. Leaf streak disease of maize is caused by Stenocarpella macrospora. Q. Stem rot of potato is caused by Sclerotium rolfsii. R. Athelia arachnoidea causes crater rot in carrot. S. Cercospora brachypus causes noble rot disease in grapes.

  1. Only P

  2. P and Q

  3. Q and R

  4. R and S

  5. Only S
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

P. Leaf streak disease is caused by the fungus, Stenocarpella macrospora in maize. Q. The causing fungal pathogen for stem rot of potato is Sclerotium rolfsii. R. Athelia arachnoidea causes crater rot in carrot. S. Grey rot or noble rot disease is caused by Botrytis cinerea in grapes. Mycosphaerella angulata and Cercospora brachypus cause angular leaf spot in grapes. Hence, only statement S is false.

Multiple choice

Match the following:

 
List A List B
A. Cottony snow mold of wheat 1. Sclerotium rolfsii
B. White leaf spot of crucifer 2. Coprinus psychromorbidus
C. Hull rot of almond 3. Rhizopus sp.
D. Southern blight of cotton 4. Pseudocercosporella capsellae

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

Cottony snow mold of wheat is caused by the fungus, Coprinus psychromorbidus. White leaf spot of crucifer is caused by Pseudocercosporella capsellae. Hull rot disease of almond is mainly caused by Rhizopus sp. Southern blight of cotton is caused by the fungal pathogen, Sclerotium rolfsii.

Hence, the sequence of codes A - 2, B - 4, C - 3, D - 1 is correct.

Multiple choice

Which of the following pairs of 'fungal disease of sugarcane - causing pathogen' is not correct?

  1. Yellow leaf spot - Cercosporidium kopkei

  2. Black stripe - Peronosclerospora sacchari

  3. Stem canker - Cytospora sacchari

  4. Red rot - Colletotrichum falcatum

  5. Brown leaf spot - Cercosporidium longipes
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Black stripe disease in sugarcane is caused by Cercospora atrofiliformis. Peronosclerospora sacchari fungus causes Downy mildew disease in sugarcane.

Multiple choice

Match the following:

 
Group - I Group - II
P. Angular leaf scorch of grapes 1. Leptosphaeria sacchari
Q. Ring spot of sugarcane 2. Phymatotrichopsis omnivore
R. Collar canker of tea 3. Pseudopezicula tetraspora
S. Cotton root rot of crucifer 4. Phomopsis theae

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

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

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

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

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

Pseudopezicula tetraspora is a fungus and causes angular leaf scorch in grapes. The causing fungus for ring spot in sugarcane is Leptosphaeria sacchari. Collar canker of tea is caused by Phomopsis theae. Cotton root rot of crucifer is caused by the fungus, Phymatotrichopsis omnivore. Hence, the correct answer is P - 3, Q - 1, R - 4, S - 2.

Multiple choice

Which property of lichens is due to usmic acid?

  1. Shape of lichens

  2. Colour of lichens

  3. Longevity of lichens

  4. Adaptability of lichens
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Special pigments give lichens a variety of colours, including red, orange, yellow and brown, especially in exposed, dry habitats.

Multiple choice

Which are the most common fungi found in lichens?

  1. Basidiomycetes

  2. Ascomycetes

  3. Actinomycetes

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

The most common fungal partner in lichens is ascomycetes, which produce reproductive spores in special cells shaped like sacs.