Emerald ash borer (EAB) is extremely destructive invasive insect that attacks ash trees. It was first found in New Hampshire in 2013, and the list of infected towns continues to grow. In 2019, 16 towns were added to the list, bringing the total number of towns to 81. Recently, Francestown, Croydon, Exeter, Durham, Sandown, Danville, New Ipswich, Greenville, and Rindge were added to the list. Unfortunately, EAB detection in Croydon signifies the first find in Sullivan County, and detection in Rindge signifies the first find in Cheshire County. Currently, 9 out of 10 of New Hampshire’s counties have EAB present—Coos is currently EAB-free. Over the summer, traps were set along the infestation border and at high risk areas to continue monitoring the spread. Check nhbugs.org for updates as more information becomes available.
EAB is transported in hardwood firewood, ash wood products, and ash nursery stock. Early detection is critical because EAB kills ash trees within 3-5 years of infestation. Biological control efforts by the NH Division of Forests and Lands through the release of parasitoids (insect predators) are on-going, and occurred at 8 sites from Atkinson to Bristol this summer.
Be careful not to confuse EAB with its many look-alikes.
The state of New Hampshire has different management zones based on where EAB has been found. Recommendations for managing woodlots and shade trees are based on the zone you are in.
- Generally infested area: Emerald ash borer is in this zone, though not necessarily in all ash trees.
- Potential expansion area: Emerald ash borer isn't known to be in the area, but the area is within 10 miles of the outer limits of the known infestation. There is a high probability emerald ash borer will spread naturally to this zone within a few years.
- Alert area: Emerald ash borer isn't known to be in the area and it is more than 10 miles from the known infestation.