Question

The disease produced by fungus Ustilago are known as smuts because
A. They parasitize cereals.
B. The affected host becomes completely black.
C. Their mycelium is black.
D. They produced sooty mass of spores.

Answer 1

Hint: The smut is a very common plant disease that mainly affects the grass family in which the corn i.e. maize, wheat, sugarcane, and sorghum are included. This disease is caused by the attacks of several species of fungi. They are cereal and crop pathogens. This disease also can be seen in the sedges, barley, and oats.

Complete answer:
Smut is a type of plant disease that primarily affects cereal grasses like corn i.e. maize, wheat, sugarcane, and sorghum. Smut can be characterized by fungal spores that pile up in soot like masses which is known as sori.
The smuts are multicellular fungi that can be characterized by fungal spores that gather in sooty masses called sori. These sori are found within blisters in seeds, leaves, stems, flower parts, and bulbs. The sori is generally disrupted into black powder and this powder is scattered by the wind. At that time, many smut fungi thrust into embryos or seedling plants, and there the development is systematic. When the plants are going to be matured, it appears externally. Other smuts are localized which further infect the actively growing tissues.
The smuts are caused by fungi that are characterized by their large numbers of teliospores. As the teliospores are dark, thick-walled, and dust-like therefore, the smuts get their name from a Germanic word which is used to refer to dirt. These fungi are mostly Ustilaginomycetes, which belong to the phylum Basidiomycota and cause plant disease. Ustilago is a genus of approximately 200 smut fungi which is parasitic on grasses. The smuts are categorized with the other basidiomycetes because of their commonalities concerning sexual reproduction.
These fungi can finally destroy the reproductive systems of the plants and form galls that darken and burst and releases fungal teliospores which can infect other nearby plants. Before infection can take place, the smuts must be going through a successful mating to form dikaryotic hyphae.

Therefore, the correct option is option D.

Note: Smut disease is one type of fungal disease which is mainly caused by the fungus belonging to the class Ustilaginomycetes of Basidiomycetes phylum. It mainly infects the inflorescence, flower, anthers, ovaries of any crop belonging to the family of grass. It can attack crops at the time of reproductive phases. This disease is characterized by the formation of the spores in the form of sooty mass.