structural:scholar_edition
Pests

Garden pests are generally plants, fungi, or animals (frequently insects) that engage in activity that the gardener considers undesirable. A pest may crowd out desirable plants, disturb soil, stunt the growth of young seedlings, steal or damage fruit, or otherwise kill plants, hamper their growth, damage their appearance, or reduce the quality of the edible or ornamental portions of the plant. Aphids, spider mites, slugs, snails, ants, birds, and even cats are commonly considered to be garden pests.

Throughout history ecosystems that have undergone rapid changes are typically those which harbor the most pests. For example, a highly and rapidly altered landscape such as modern canola fields in the Americas can be a breeding ground for pests of the Brassicaceae family. A natural ecosystem will typically regulate pest levels through many biological means whether that be the natural introduction of a disease or an increase in the population of a predator species of animal.

Because gardeners may have different goals, organisms considered "garden pests" vary from gardener to gardener. Tropaeolum speciosum, for example, may be considered a desirable and ornamental garden plant, or it may be considered a pest if it seeds and starts to grow where it is not wanted. As another example, in lawns, moss can become dominant and be impossible to eradicate. In some lawns, lichens, especially very damp lawn lichens such as Peltigera lactucfolia and P. membranacea, can become difficult to control and are considered pests.