Question

Ergot of rye is caused by a species of

• A. Uncinula
• B. Ustilago
• C. Claviceps
• D. Phytophthora

Answer 1

The Correct Option is C

Ergot of rye is a disease caused by a fungus from the Claviceps genus, specifically Claviceps purpurea. This fungus infects cereal grains like rye and produces alkaloids that are toxic to humans and animals upon consumption.

Let's analyze why Claviceps is the correct choice, while the others are not:

1. Uncinula: This is a genus of fungi responsible for causing powdery mildew in various plants, not ergot in rye.
2. Ustilago: This genus includes smut fungi that primarily infect maize and other cereals but do not cause ergot of rye.
3. Claviceps: This is the correct answer. Members of this genus, particularly Claviceps purpurea, infest rye and related cereals, forming hard, dark structures known as sclerotia, which replace the grain. These contain toxic alkaloids causing ergotism if ingested.
4. Phytophthora: This is a genus of oomycetes, which are not true fungi but are often called "water molds." They are known for causing diseases like late blight in potatoes but are unrelated to ergot in rye.

In conclusion, the correct answer is Claviceps because it specifically references the genus responsible for producing ergot in rye.