Within-tree Distribution & Host Range
Efforts to eradicate ALB began relatively soon after the insects discovery in New York (1996), and later in Illinois (1998) and New Jersey (2002). To be successful, eradication requires locating all infested trees and destroying them. To locate infested trees, inspectors look for ALB oviposition pits and exit holes on the bark surface as well as boring dust (frass) that larvae expel from the trees as they tunnel. Knowing where ALB attacks first can help inspectors locate infested trees, especially in areas with low populations. It is also important to know the host range of ALB so that surveyors can efficiently conduct tree surveys.
We recorded the number of ALB life stages found at several locations along the main trunk and major branches of naturally infested Populus (poplar), Salix (willow), and Ulmus (elm) trees in China, and Acer (maple), Fraxinus (ash), and Ulmus (elm) in Chicago, Illinois. We found that ALB typically initiated attack near the base of the crown along both the trunk and main branches. The one exception was on Populus trees in China that had branches along the entire trunk. On such popular trees, ALB initiated attack along the lower trunk.
As a result of inspecting trees at different seasons of the year, we also obtained some life history data. For example, we noted that larvae were the dominant overwintering stage for ALB in both countries. Using a host suitability index, we found that ALB survival was higher on Populus and Salix than Ulmus in China, and generally higher on Acer and Ulmus than Fraxinus in Chicago.
As of 2007, 1465 ALB-infested trees had been located and cut in Chicago. These 1465 trees represented 11 genera. In decreasing order of tree frequency they included the genera Acer, Ulmus, Fraxinus, Aesculus (horsechestnut), Betula (birch), Salix, Celtis (hackberry), Malus (apple), Pyrus (pear), Sorbus (mountain ash), and Tilia (basswood). When the proportion of each genus of infested street trees was compared to its proportion of all Chicago street trees based on a 2003 inventory it was noted that ALB showed a significant preference to infest trees in the genera Acer and Ulmus.
Results from our studies will be used by inspectors when surveying trees for signs of ALB infestation. Our findings will assist surveyors in knowing which tree species are most highly preferred and where to look first during the inspections. Our results can be used by forest health managers throughout the US as well as in other countries where ALB has been detected.
Haack, Robert A.; Bauer, Leah S.; Gao, Rou-Tong; McCarthy, Joseph J.; Miller, Deborah L.; Petrice, Toby R.; Poland, Therese M. 2006. Anoplophora glabripennis within-tree distribution, seasonal development, and host suitability in China and Chicago. Great Lakes Entomologist 39: 169-183.
- Robert Haack, USDA Forest Service- Northern Research Station Research Entomologist (Retired)
- Therese Poland, USDA Forest Service- Northern Research Station Research Ecologist
- Leah Bauer, USDA Forest Service- Northern Research Station Research Entomologist
- Toby Petrice, USDA Forest Service- Northern Research Station Entomologist
- Debbie Miller, USDA Forest Service- Northern Research Station Entomologist
- Joseph McCarthy, Bureau of Forestry, Chicago
- Rui-Tong Gao, Chinese Academy of Forestry, Beijing
Last Modified: 07/13/2017