Microbes and Plant Diseases

Agaricus bisporus is cultivated in more than 70 countries and is one of the most commonly and widely consumed mushrooms in the world. 

A mass of hyphae is called mycelium. A hypha is an elongated cell with many nuclei and branches.

Late blight of potato is a fungal disease. 

Athlete's foot and dhobi's itch are examples of fungal skin infections.

Abiotic factors are non-living physical or chemical components of the environment. Moisture, temperature, and humidity are abiotic factors that can cause grain spoilage during storage. Fungi, mites, and rodents are biotic (living) factors.

Late blight of potato is caused by the fungus Phytophthora infestans (though technically an oomycete, historically classified as a fungus). This devastating disease caused the Irish Potato Famine. Viruses, amoebae, and bacteria do not cause late blight - they cause other plant diseases but not this specific condition.

Ringworm (dermatophytosis) is a fungal infection of the skin, hair, or nails caused by dermatophytes like Trichophyton, Microsporum, and Epidermophyton. These fungi digest keratin and cause characteristic ring-shaped rashes. Bacteria cause different infections (like staphylococcal or streptococcal), viruses cause conditions like chickenpox or measles, and protozoa cause diseases like malaria or dysentery.

Yellow vein mosaic of okra (Bhindi) is a viral disease caused by Bhendi yellow vein mosaic virus (BYVMV), a Geminivirus. It is transmitted by the whitefly Bemisia tabaci and causes characteristic yellow mosaic patterns on leaves, vein thickening, and stunted plant growth. Bacterial diseases include citrus canker or blight, fungal diseases include rusts and smuts, and protozoa do not typically affect plants.

Mushroom is called 'heterotrophic' as it depends on others for food. Some are saprophytes, and some are parasites.

Fungi are called saprophytes as they live on dead or decaying plant or animal matter.

Citrus canker is caused by bacteria, which spreads through air. 

Rust of wheat is caused by fungi and it can spread by means of air or seeds. 

Onychomycosis refers to the fungal infection of nails. It causes nail abnormalities.

Viruses have no useful characteristic for humans.

(i) Statement (1) is correct. Yes, thermophilic organisms are those organisms, which are adapted to living in high temperatures. (ii) Statement (2) is incorrect. Pasteurization of milk takes place at 60^oC. At this temperature, it limits the growth of milk borne infectious diseases.