Pest (organism) Pest (organism) A pest is an animal or plant detrimental to humans or human concerns including crops, livestock, and forestry. The term is also used of organisms that cause a nuisance, such as in the home. An older usage is of a deadly epidemic disease, specifically plague. In its broadest sense, a pest is a competitor of humanity. A pest is any living organism, whether animal, plant or fungus, which is invasive or troublesome to plants or animals, human or human concerns, livestock, or human structures. It is a loose concept, as an organism can be a pest in one
True-breeding organism plants for gardeners are F1 hybrids, which if propagated from seed will produce F2 hydrids which are quite different from their parents; the F1 hybrids therefore don't breed true. True-breeding organism A true-breeding organism, sometimes also called a purebred, is an organism that always passes down certain phenotypic traits (i.e. physically expressed traits) to its offspring of many generations. An organism is referred to as true breeding for each trait to which this applies, and the term "true-breeding" is also used to describe individual genetic traits. In Mendelian genetics, this means that an organism must be homozygous for every trait