Forest insects and diseases have widespread ecological and economic impacts on the forests of the United States and may represent the most serious threats to the Nation’s forests (Logan and others 2003, Lovett and others 2016, Tobin 2015). U.S. law therefore authorizes the U.S. Department of Agriculture Forest Service to “conduct surveys to detect and appraise insect infestations and disease conditions and man-made stresses affecting trees and establish a monitoring system throughout the forests of the United States to determine detrimental changes or improvements that occur over time, and report annually concerning such surveys and monitoring” (FHP 2020). Insects and diseases cause changes in forest structure and function, species succession, and biodiversity, which may be considered negative or positive depending on management objectives (Edmonds and others 2011). Nearly all native tree species of the United States are affected by at least one injury-causing insect or disease agent, with exotic agents on average considerably more severe than native ones (Potter and others 2019a). Additionally, the genetic integrity of several native tree species is highly vulnerable to exotic diseases and insects (Potter and others 2019b).
Potter, Kevin M.; Paschke, Jeanine L.; Koch, Frank H.; Berryman, Erin M. 2021. Chapter 2 - Broad-scale patterns of insect and disease activity across the 50 United States from the National Insect and Disease Survey, 2019. In: Potter, K.M.; Conkling, B.L., eds. Forest health monitoring: national status, trends, and analysis 2020. Gen. Tech. Rep. SRS-261. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Research Station: 27-57.