Correct Answer: fungus

Solution : The correct option is fungus .

A genus of fungi called Puccinia contains different species of rusts. The most well-known hosts of these parasitic rusts are plants. The rust infections that affect plants are caused by Puccinia species. Cultivars such as cereals, fruits, vegetables, and ornamental plants are all susceptible to these diseases. The spore-producing structures of rust-like fungi, such as those in the Puccinia genus, are responsible for their name. On the surface of affected plant tissues, they frequently release powdery spores that resemble rusty or reddish-brown pustules.