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

‘Wart’ disease of potato is caused by

  1. Polyscytalum pustulans

  2. Synchytrium endobioticum

  3. Sclerotinia sclerotiorum

  4. Phytophthora infestans

  5. Erysiphe cichoracearum
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The causative agent for wart disease of potato is Synchytrium endobioticum.

Multiple choice

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

  1. Pyrenophora teres

  2. Rhynchosporium secalis

  3. Blumeria graminis

  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 one of the following pairs is not correct about fungal diseases of sugarcane-causing pathogen?

  1. Yellow leaf spot - Cercosporidium kopkei

  2. Black stripe - Peronosclerospora sacchari

  3. Stem canker - Cytospora sacchari

  4. Red rot - Cercosporidium 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

Which of the following statements is/are false? A. Tropical cotton rust of cotton is caused by Phakopsora gossypii. B. Puccinia striiformis causes scald disease in barley. C. The causative agent for cottony snow mold of wheat is Tilletia controversa.

  1. A only

  2. B only

  3. C only

  4. A and B only

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

A. Tropical cotton rust of cotton is caused by Phakopsora gossypii. B. The causative fungal agent for stripe yellow rust of barley is Puccinia striiformis. Scald disease of barley is caused by the fungus Rhynchosporium secalis. C. Cottony snow mold disease of wheat is caused by the fungus Coprinus psychromorbidus. Dwarf bunt of wheat is caused by Tilletia controversa. Hence, statements B and C are false.

Multiple choice

Which of the following statement(s) is/are false? P. The causing agent for Areolate leaf spot in citrus is Nematospora coryli. Q. Nectria canker disease is caused by Erysiphe cichoracearum. R. Glomerella cingulata causes bitter rot in peanut.

  1. P only

  2. Q only

  3. R only

  4. P and Q

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

P. The causative agents for Areolate leaf spot in citrus are- Thanatephorus cucumeris, Pellicularia filamentosa and Rhizoctonia solani. Dry fruit rot is caused by Nematospora coryli in citrus. Q. 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. R. Bitter rot of peanut is caused by the fungal pathogen Glomerella cingulata. Hence, P and Q are false statements.

Multiple choice

Match the Group-I (fungal diseases) with Group-II (causative pathogens) ||| |---|---| |Group-I |Group-II| |P. Blue mold rot of carrot|1. Macrophomina phaseolina| |Q. Fly speck of citrus|2. Penicillium expansum| |R. Pink leaf of coffee|3. Phanerochaete salmonicolor| |S. Charcoal rot of maize|4. Schizothyrium pomi|

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

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

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

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

  5. P - 2, Q - 4, R - 3, S - 1
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Blue mold rot of carrot is caused by the fungal pathogen Penicillium expansum. The causative agent for fly speck in citrus is Schizothyrium pomi. Phanerochaete salmonicolor causes pink leaf disease in coffee. Charcoal rot of maize is caused by the fungus Macrophomina phaseolina. Hence, the correct answer is P - 2, Q - 4, R - 3, S - 1.

Multiple choice

Which of the following is/are the causative pathogen(s) for ‘Violet root rot’ of apple? A. Chondrostereum purpureum B. Helicobasidium mompa C. Peltaster fructicola D. Leptodontidium elatius E. Gloeodes pomigena

  1. A only

  2. B only

  3. A and B

  4. B and C

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

Violet root rot is caused by Helicobasidium mompa. Sooty blotch causing fungal pathogens are - Peltaster fructicola, Geastrumia polystigmatis, Leptodontidium elatius, Gloeodes pomigena. Silver leaf disease is caused by Chondrostereum purpureum in apple. Hence, B is the causative agent responsible for violet root rot in apple.

Multiple choice

‘Narrow brown leaf spot’ disease of rice is caused by

  1. Cercospora oryzae and Sphaerulina oryzina

  2. Cochliobolus miyabeanus and Bipolaris oryzae

  3. Tilletia barclayana and Neovossia horrid

  4. Microdochium oryzae and Rhynchosporium oryzae

  5. Thanatephorus cucumeris and Rhizoctonia solani
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Narrow brown leaf spot of rice is caused by Cercospora oryzae and Sphaerulina oryzina.

Multiple choice

The fungus (fungi) responsible for ‘Bird’s eye rot’ in grapes is/are A. Mycosphaerella angulata B. Elsinoe ampelina C. Sphaceloma ampelinum

  1. A only

  2. B only

  3. C only

  4. A and B

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

The causing fungal pathogens responsible for bird’s eye rot are Elsinoe ampelina and Sphaceloma ampelinum. Angular leaf spot of grapes is caused by the fungus Mycosphaerella angulata. Hence, the correct answer is Elsinoe ampelina and Sphaceloma ampelinum.

Multiple choice

Match the diseases in Column-I with causative pathogens in Column-II and select the correct answer ||| |---|---| |Column-I |Column-II| |P. Tropical cotton rust|1. Phakopsora gossypii| |Q. Powdery mildew of pea|2. Trametes versicolor| |R. Wood rot of pear|3. Helminthosporium solani| |S. Silver scurf of potato|4. Erysiphe pisi| | |5. Polyscytalum pustulans|

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

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

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

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

  5. P - 5, Q - 4, R - 2, S - 3
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Tropical cotton rust is caused by the fungus Phakopsora gossypii. The causative agent for powdery mildew in pea is Erysiphe pisi. Wood rot of pear is caused by the fungus Trametes versicolor. Helminthosporium solani causes silver scurf disease in potato. Hence, the correct answer using the codes is P - 1, Q - 4, R - 2, S - 3.