EXOTIC FOREST INSECT PESTS AND THEIR IMPACT ON FOREST MANAGEMENT

摘要

More than 4500 exotic organisms are now established in the United States, of which over 400 are insects that feed on trees and shrubs. While most exotic insects cause little or no damage, a few have become serious pests and have greatly altered nativeforest ecosystems. Three of the most recently introduced exotic forest pests are the pine shoot beetle, the Asian longhorned beetle, and the emerald ash borer. The initial response to the detection of a new exotic forest insect pest involves verifying the identity and establishment of the insect, activating policy and response groups composed of regulatory and scientific professionals, initiating a scoping survey, and deciding if a quarantine should be established. Detailed survey and management options are then developed. Survey, eradication and management approaches depend on available knowledge of the biology of the particular insect pest. Surveys may be conducted with traps or by visual inspection. Management options may include tree removal, application of insecticides, and introduction or augmentation of natural enemies. The success of the management tactics employed is evaluated. If eradication or containment of the initial infestation is unsuccessful, long-term management strategies are implemented. Long-term forest management strategies include rogueing and burning infested trees, avoiding transportation of infested material, thinning of stands to improve tree vigor, replanting and encouraging tolerant tree species, increasing tree diversity, and selecting and breeding resistant trees. As world trade and the risk for new introductions of exotic insects continue to increase, forest managers must remain aware of potential new pests and quarantine regulations and continually monitor and improve the health, vigor, and diversity of forest stands.