Question

Parasitic alga is – Tea and Coffee leaves are infected by
(a) Cephaleuros
(b) Sargassum
(c) Oedogonium
(d) Ulothrix

Answer 1

As this plant pathogen is an algal species, it thrives under similar conditions as other algal organisms. They prefer moist, humid weather. Areas with frequent rain, and consider high temperatures are where this pathogen flourishes.

Complete answer:
Cephaleuros is a genus of parasitic thalloid green algae that consist of around 14 species. Its common name is red rust. Specimens can reach around 10 mm in size. Dichotomous branches are formed. Cephaleuros virescens is an algal plant pathogen that infects tea and coffee by causing algal leaf spot or algal rust. Most ordinarily Cephaleuros virescens are identified by the leaf spots it causes.
Sargassum may be a genus of brown macroalgae within the Fucales. Various species are distributed all over the temperate and tropical oceans of the world. They typically inhabit shallow water and coral reefs, and the genus is widely known for its planktonic species. Oedogonium, a genus of filamentous chlorophyte (family Oedogoniaceae) , commonly found in quiet bodies of freshwater. They frequently are connected to other plants or exist as a free-floating mass. Oedogonium filaments are typically unbranched and just one cell thick. Ulothrix may be a genus of green algae within the family Polytrichaceae. Generally present in fresh and marine water. Its cells are normally as broad as they're long, and they thrive within the low temperatures of spring and winter.
So, the correct answer is ‘(a) Cephaleuros’.

Note: Often, leaf spot caused by Cephaleuros virescens isn't damaging enough to the host plant’s vigor or crop yield and thus generally doesn't warrant management. If however, the crop is very susceptible, a sort of integrated pest management is often wont to prevent the spread and infection of the disease.