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 causing bacterial pathogen(s) for ‘Sheath brown rot’ in rice is/are A. Pseudomonas fuscovaginae B. Xanthomonas oryzae C. Burkholderia glumae D. Erwinia chrysanthemi

  1. A only

  2. B only

  3. A and B

  4. B and C

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

In rice, the causative bacteria for sheath brown rot is Pseudomonas fuscovaginae. Xanthomonas oryzae causes leaf streak and blight diseases in rice. Grain rot disease is associated with the bacteria Burkholderia glumae in rice. Foot rot of rice is caused by the bacteria Erwinia chrysanthemi. Hence, A is the only causative bacterial agent responsible for sheath brown rot in rice.

Multiple choice

Which of the following statement(s) is/are false? P. Crown gall of mango is caused by Agrobacterium tumefaciens. Q. Erwinia carotovora causes fruit rot disease in tomato. R. Striatura ulcerosa disease in hemp is caused by Pseudomonas cannabina.

  1. P only

  2. Q only

  3. R only

  4. P, Q

  5. Q, R
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

P. The causative bacterial agent for crown gall in mango is Agrobacterium tumefaciens. Q. Fruit rot disease of tomato is caused by the bacteria Erwinia carotovora. R. The causative agent for Striatura ulcerosa in hemp is Pseudomonas amygdali. Pseudomonas cannabina causes blast disease in hemp. Hence, only R is the false statement.

Multiple choice

The causing bacterial pathogen(s) for ‘Marbled fruit’ disease in pineapple is/are A. Erwinia carotovora B. Erwinia herbicola C. Acetobacter peroxydans

  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

Erwinia carotovora causes soft rot disease in pineapple. The causing bacterial pathogens responsible for marbled fruit disease of pineapple are Acetobacter peroxydans and Erwinia herbicola. Hence, the correct answer is Elsinoe ampelina and Sphaceloma ampelinum.

Multiple choice

Identify the true statement (s). P. Phony disease of peach is caused by the bacteria Xanthomonas arboricola. Q. Brown spot and blight diseases in pea are caused by Pseudomonas syringae. R. Erwinia carotovora causes soft rot disease in pineapple.

  1. Only P

  2. Only Q

  3. Only R

  4. P and Q

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

P. The causative bacterial pathogen for phony disease of peach is Xylella fastidiosa. Yellow spot disease is caused by the bacteria Xanthomonas arboricola in peach. Q. Pseudomonas syringae causes brown spot and blight diseases in pea.
R. Soft rot disease of pineapple is caused by the bacteria Erwinia carotovora. Hence, both statements. Q and R, are true.

Multiple choice

Match the bacterial diseases in Group-I with causative pathogens in Group-II ||| |---|---| |Group- I |Group-II| |P. Mosaic of wheat|1. Ralstonia solanacearum| |Q. Graville wilt of tobacco |2. Pseudomonas fluorescens | |R. Leaf scald of sugarcane|3. Clavibacter michiganensis| |S. Pink eye of potato|4. Drechslera teres| | |5. Xanthomonas albilineans|

  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

Mosaic disease of wheat is caused by the bacteria Clavibacter michiganensis. The causative bacteria for graville wilt in tobacco is Ralstonia solanacearum. Leaf scald disease of sugarcane is caused by the bacteria Xanthomonas albilineans. Pink eye disease of potato is caused by the bacteria Pseudomonas fluorescens. Hence, the correct sequence of codes is P - 3, Q - 1, R - 5, S - 2.

Multiple choice

Which of the following is NOT a fungal disease?

  1. Aspergillosis

  2. Blastomycosis

  3. Leishmaniasis

  4. Candidiasis

  5. Histoplasmosis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Leishmaniasis is a disease caused by protozoan parasites of the genus Leishmania and spread by the bite of certain types of sandflies.

Multiple choice

Match the entries in Column I (Crop disease) and Column II (Causative agent) and select the correct answer.

 
Column I
Column II
P. Bacterial wilt of tomato 1. Peronospora parasitica
Q. Downy mildew of Crucifers 2. Ralstonia solanacearum
R. Citrus canker 3. Ustilago maydis
S. Common smut of corn 4. Xanthomonas axonopodis

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

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

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

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

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

Correct answer. Bacterial wilt of tomato is caused by the bacterium Ralstonia solanacearum. Downy mildew of Crucifers is caused by Peronospora parasitica. Citrus canker is a disease affecting Citrus species caused by the bacterium Xanthomonas axonopodis. Common smut of corn is caused by Ustilago maydis.

Multiple choice

Match the crop diseases listed in Group I with causative agents in Group II.

 
Group I
Group II
P. Downy Mildew of Cucurbits 1. Phytophthora infestans
Q. Downy mildew of grape 2. Pseudoperonospora cubensis
R. Late blight of potato 3. Phytophthora nicotianae
S. Black Shank of Tobacco 4. Plasmopara viticola

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

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

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

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

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

Correct answer. Downy Mildew of Cucurbits is caused by Pseudoperonospora cubensis. Downy mildew of grape is caused by Plasmopara viticola. Late blight of potato is caused by Phytophthora infestans. Black Shank of Tobacco is caused by Phytophthora nicotianae.

Multiple choice

Which of the following 'disease: causative agent' matches is incorrect?

  1. Coffee leaf rust: Hemileia vastatrix

  2. Black sigatoka of bananas: Mycosphaerella fijiensis

  3. Early blight of potato: Phytophthora infestans

  4. Rice Blast: Magnaporthe oryzae

  5. Ergot of rye: Claviceps purpurea
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Early blight of potato is caused byAlternaria solani. Late blight of potato is caused by Phytophthora infestans.

Multiple choice

The causative agent of barley brown rust is

  1. Puccinia melanocephala

  2. Puccinia kuehnii

  3. Puccinia hordei

  4. Puccinia arachidis

  5. Puccinia menthae
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Puccinia hordei is a species of rust fungus that causes barley brown rust.