Large-scale patterns of insect and disease activity in the conterminous United States, Alaska and Hawaii from the national insect and disease survey, 2015

Potter, K.M., and J.L. Paschke. 2017. Large-scale patterns of insect and disease activity in the conterminous United States, Alaska and Hawaii from the national insect and disease survey, 2015. Chapter 2 in K.M. Potter and B.L. Conkling, eds., Forest Health Monitoring: National Status, Trends and Analysis, 2016. General Technical Report SRS-222. Asheville, North Carolina: U.S. Department of Agriculture, Forest Service, Southern Research Station. p. 21-42.

Monitoring the occurrence of forest pest and pathogen outbreaks is important at regional scales because of the significant impact insects and disease can have on forest health across landscapes. National insect and disease survey data collected in 2015 by the Forest Health Protection Program of the Forest Service and partners in State agencies identified 70 different mortality-causing agents and complexes on 2.23 million ha in the conterminous United States, and 58 defoliating agents and complexes on approximately 4.85 million ha. Geographic hot spots of forest mortality were associated with bark beetle infestations (mostly pinyon ips, fir engraver, western pine beetle, mountain pine beetle, and spruce beetle) in the West, and with hemlock wooly adelgid and emerald ash borer in the East. Hot spots of defoliation were associated with western spruce budworm in the West, and with yellow poplar weevil, loblolly pine sawfly, gypsy moth, winter moth, and spruce budworm. Mortality was recorded on a very small proportion of the surveyed area in Alaska. The most important defoliation agents in Alaska were aspen leafminer and willow leaf blotchminer. In Hawai‘i, approximately 18 000 ha of mortality caused by rapid ʻōhiʻa death was detected on the Big Island.