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.
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.
Garden pest control
There are many ways by which unwanted pests are removed from a garden. The techniques vary depending on the pest, the gardener's goals, and the gardener's philosophy. For example, snails may be dealt with through the use of a chemical pesticide, an organic pesticide, hand-picking, barriers, or simply growing snail-resistant plants.
Pest control is often done through the use of pesticides, which may be either organic or artificially synthesized. Pesticides may affect the ecology of a garden due to their effects on the populations of both target and non-target species. For example, unintended exposure to some neonicotinoid pesticides has been proposed as a factor in the recent decline in honey bee populations. A mole vibrator can deter mole activity in a garden.
Other means of control include the removal of infected plants, using fertilizers and biostimulants to improve the health and vigour of plants so they better resist attack, practising crop rotation to prevent pest build-up, using companion planting, and practising good garden hygiene, such as disinfecting tools and clearing debris and weeds which may harbour pests.