Impacts of emerald ash borer and Sirex noctillo in the northeastern US

Background/Question/Methods Many non-native pests have been introduced into the United States over the last 100 years resulting greatly altered ecosystems and large economic losses. Emerald ash borer (EAB), Agrilus planipennis Fairmaire, was recently identified in Michigan. Larvae of this wood-boring beetle feed in the inner bark (phloem) of native ash, Fraxinus spp., trees and cause 100% tree mortality. Recent detections in Ontario and Pennsylvania portend EABs imminent arrival to New York forests. Sirex noctilio, a wood-boring woodwasp of Pinus spp., was recently found in New York forests and potential impacts of this particular pest are unknown. Our objectives were to investigate ecological, economic, and social impacts of these two pests for the northeastern United States.

Results/Conclusions

Ecological effects of emerald ash borer will be most profound in areas of high ash composition, e.g., riparian corridors, northern wetlands. Upland forests do have an ash component and organisms that are ash specialists will most certainly be lost along with ash. Economic impacts will be greatest for specialty industries that rely heavily on ash, e.g., baseball bat and tool handle manufacturers, as well as urban areas whose forests tend to have large numbers of ash. Impacts of Sirex noctilio are less well defined. To date, this insect has only been documented to kill suppressed non native pines in New York forests. The major cause for concern with this organism does not appear to be in the northeast, but in the south. Southern pine plantations are likely susceptible based on the amount of tree mortality experienced after introduction of Sirex on other continents where these same pine species were planted. We found quantifying stumpage values for economic impacts to be relatively straightforward using forest service FIDO data. However, quantification of more detailed economic costs to industries and communities relying on those industries as well as quantification of ecological impacts were considerably more challenging. Another particularly difficult area was defining social impacts. For example, black ash is irreplaceable to traditional black ash basket makers and the loss of this species will be felt not only financially but far more importantly socially and culturally.