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 among the following does not characterises ectomycorrhiza?

  1. Ectomycorrhizas forms between fungi and the roots of around 5% of plant species.

  2. Ectomycorrhizal fungi do not penetrate their host’s cell walls.

  3. Many EcM fungi have fruiting bodies.

  4. The hyphae extending outward into the soil from one ectomycorrhiza can infect other nearby plants.

  5. The extramatrical mycelia of ectomycorrhizas acts as transport structures.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Ectomycorrhiza forms between fungi and the roots of around 2% of plant species. These tend to be composed of woody plants, including species from the birch, dipterocarp, myrtle, beech, willow, pine and rose families. Most plants form with endomycorrhizae.

Multiple choice

Gibbrellin is obtained from__________.

  1. gibberella (an algae)

  2. gibberella (a fungus)

  3. basidiolichen

  4. bacterium

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

Gibberellin is obtained from gibberella fujikuroi, which is a fungus.

Multiple choice

Downy mildew of crucifers is caused by

  1. Puccinia graminis

  2. Erysiphe graminis

  3. Erysiphe polygoni

  4. Peronospora parasitica

  5. Colletotricum falcatum
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Downy mildew of crucifers is caused by Peronospora parasitica.

Multiple choice

Identify the mismatched pair of disease and its causative agent.

  1. Black root rot of cotton: Thielaviopsis basicola

  2. Black rot of crucifers: Xanthomonas campestris

  3. Gray mold of hemp: Agrobacterium tumefaciens

  4. Downy mildew of mustard: Peronospora parasitica

  5. Bottom rot of lettuce: Rhizoctonia solani
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The most important disease of hemp is gray mold, caused by the fungus botrytis cinerea. Crown gall of hemp is caused by agrobacterium tumefaciens.

Multiple choice

__________ is caused by a virus.

  1. False eyespot of wheat

  2. Wheat yellow leaf

  3. Pink seed of wheat

  4. Downy mildew of wheat

  5. Ergot of wheat
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Wheat yellow leaf virus is a wheat, barley, rye and oat pathogenic of the family Closteroviridae. 

Multiple choice

Which organism causes white mold of pepper?

  1. Botrytis cinerea

  2. Sclerotinia sclerotiorum

  3. Peronospora tabacina

  4. Stemphylium solani

  5. Macrophomina phaseolina
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

White mold of pepper is caused by Sclerotinia sclerotiorum.

Multiple choice

Which of the following matches of crop disease: causative agent is not correct?

  1. Coffee leaf rust: Hemileia vastatrix

  2. Ergot of Rye: Claviceps purpurea

  3. Early blight of potato: Phytophthora infestans

  4. Crown rust of oats: Puccinia coronata

  5. Halo blight of beans: Pseudomonas syringae
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Early blight of potato caused by the fungus alternaria solani. Phytophthora infestans is an oomycete that causes the serious potato disease known as late blight of potato.

Multiple choice

What causes northern corn leaf blight?

  1. Puccinia sorghi

  2. Bipolaris maydis

  3. Exserohilum turcicum

  4. Puccinia polysora

  5. Cercospora zeae-maydis
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Northern corn leaf blight is caused by fungus exserohilum turcicum.