Forest pest control or forest protection refers to the approaches and tactics for protecting forests from insects and pathogens. The traditional view is that plant-feeding insects and pathogens are destructive agents that must be controlled to protect forest resources. Pest activity generally is triggered by specific changes in host-tree condition and density that often result from forest management practices. Integrated forest pest management represents the current approach to optimize accomplishment of forest management goals by evaluating the costs and benefits of various forest species for production of multiple resources. A number of pest management tools are available, including computerized models that facilitate evaluation and decision-making, and a variety of chemical, biological, and silvicultural techniques for manipulating pest abundances. Plant pathology

A variety of organisms can interfere with forest management objectives. Most of these are insects, fungal pathogens, and nematodes. Insects are responsible for vectoring some microbial pathogens, and pathogens frequently increase the vulnerability of infected trees to insects.

A critical first step in integrated forest pest management is identification of the forest management goals. If not justified by contribution to forest management goals, that is, optimized production of forest resources, suppression represents unnecessary costs in terms of time, money, and environmental quality.

Forest managers must be aware of potential impediments, including effects of insect and pathogens, in the accomplishment of their goals. Effective management requires information on which species can affect forest resources and at what densities. The relative threats of potential pests to particular management goals must be weighed carefully to determine tolerable or optimal abundances. Substantial data are needed to evaluate pest status. Examples of information needed for assessment include current and projected abundances of potential pests, action thresholds (abundance at which loss of resources exceeds costs of control efforts), environmental conditions favorable to various pests, and factors that influence the effectiveness of control tactics. This information can be used to project losses or gains for various forest resources as a result of specific insect or pathogen species. Such projections can be improved greatly by use of computerized models that synthesize available data and permit simulation and prediction of resource production under various environmental conditions or pest management scenarios.

The objective of pest suppression should be maintenance of pest populations below their action thresholds. Elimination of native species is impractical and would interfere with their natural ecological functions. Reducing abundances to levels that no longer interfere with management goals is sufficient. However, preventing the establishment of exotic species may be critical to sustainability of forest resources.

A variety of control options are available, but many have limited utility against particular pest species. Pesticides can be applied as aerial or ground aerosols or as fumigants. Fungicides are relatively ineffective against fungal pathogens that generally are protected from exposure. Microbial pathogens and antibiotics can be delivered as aerosols or applied to surfaces exposed to infectious agents. Other biological control options include augmentation of natural enemy populations. Biological control is most effective when the predator, parasite, or pathogen selectively and efficiently preys on the pest species. Pheromones are chemicals produced by animals, most commonly to attract potential mates. In some species, especially of bark beetles, a combination of attractive and repellent pheromones limits population density and reduces competition for resources. Silvicultural options include thinning, prescribed understory burning, and fertilization to reduce competition among trees for light, water, and nutrient resources. Thinning also slows spread of insects and pathogens between trees.

A goal of integrated forest pest management is variation in control tactics over time and across landscapes to minimize development of resistance to particular control options. Fungistat and fungicide Insect control, biological Pesticide Silviculture