A plant disease that cannot be eliminated by a chemical means. Some viruses have created stripped tulips. Most are feared by growers.

A class of disease-causing particles that are resistant to antibiotics and antifungals. Influenza ("the flu") and the common cold are caused by viruses.

a tiny, non-cellular, disease-causing molecule

kita whakamate A disease-producing, microscopic particle that can easily make copies of itself.

A small, very simple organism, with the ability to cause disease

a kind of organism that causes disease

A living organism capable of causing disease.

(n) An ultra-microscopic and filterable agent, many diseases of plants and animals are due to it, it may be a living organism or a complex communicable molecule