Early detection is vital for success in combating invasive pests
Once established on a widespread scale, hope for eradication of unwanted invasive pests is unlikely. Early detection, teamed with a rapid, efficient response, is our best hope to reduce damage caused by these unwanted pests.
The USDA Animal and Plant Health Inspection Service (APHIS) recently confirmed the presence of emerald ash borer (EAB) in Baraga County in Michigan’s Upper Peninsula. Since it was first detected in the Detroit area in 2002, this destructive invader has steadily marched across the state and much of the country. Currently, only three counties in the extreme western Upper Peninsula remain outside the EAB quarantine area. To date, EAB is established in at least 30 states plus the Canadian provinces of Ontario and Quebec.
There has been some success in slowing the rate of ash mortality caused by EAB, but this beetle will likely be with us forever. When the insect was first detected, what was originally thought to be a localized area infestation in the greater Detroit metro area turned out to be much more extensive. People had unknowingly moved infested ash nursery trees, firewood and logs out of southeast Michigan, resulting in EAB infestations scattered across much of the state.
Emerald ash borer has already caused the loss of millions of ash trees in the state and hundreds of millions of ash trees across much of the eastern U.S. This pest may be a worst case example of what can happen to our forests and urban forests as a result of ever-increasing global trade and travel. Early detection of invasive pests remains a key element of protecting our resources. When a newly arrived invasive pest is detected early, a rapid response to eradicate, contain or slow the spread efforts can be successful. Some insects are more likely to be detected early than others. For example, many moths produce long range pheromones to attract mates. Traps baited with that same pheromone can be highly effective. On the other hand, many invasive beetles such as EAB do not produce long-range pheromones. These insects are much more difficult to find when populations are low.
Regulations are in place to help prevent the introduction of new invasive pests into Michigan in nursery trees, firewood and various imported commodities. However, given the amount of material that comes into the U.S. and moves between states, new pests will inevitably be introduced and some of those will become established. Unwanted forest insects and diseases currently on our radar include Asian longhorn beetle, hemlock woolly adelgid and thousand cankers disease. These invasive pests have already become established in or adjacent to our state, and all represent important threats to our forests and urban forests.
In an effort to improve the likelihood that new invasive pest will be found sooner rather than later, Michigan State University Extension has developed the Eyes on the Forest program, thanks to funding assistance from the Michigan Invasive Species Grant Program. A major aspect of this program involves a network of Sentinel Trees monitored by volunteers from around the state. Each volunteer agrees to monitor the condition of one or more Sentinel Trees once or twice a year and submit the data to the on-line Sentinel Tree database. Ideally, with enough enthusiastic participation and diligent inspection, we hope that new populations of invasive forest pests can be identified early enough for control measures to be effective.