Hemlock woolly adelgid (Adelges tsugae) is a small invasive insect native to Asia that is a threat to the health and sustainability of eastern hemlock (Tsuga canadensis) and Carolina hemlock (Tsuga caroliniana). Hemlock woolly adelgid, which is related to aphids and scales, feeds on the hemlock’s tissues and the build-up of large populations can result in the decline and death of hemlock trees. Hemlock woolly adelgid was first detected in New Hampshire in 1999. Since 2000, the New Hampshire Department of Agriculture, Markets & Food and the New Hampshire Department of Resources and Economic Development have maintained a joint quarantine on the movement of hemlock nursery stock and hemlock forest products into the state. The below links provide more information on hemlock woolly adelgid, its history in the US and in New Hampshire, control measures, and the specifics of the Hemlock Woolly Adelgid Exterior Quarantine.