Survey and Detection: Now you see them, now you don’t...
Almost all of the new ALB infestations have been found by members of the general public, not pest specialists. For this reason public awareness on a nationwide scale is absolutely essential for increasing the likelihood of detecting additional infestations early. However, once an infestation is discovered, a careful and methodical survey of all potential host trees, both on public and private property is necessary.
Detection of infested trees within known areas of infestation have proved extremely difficult for several reasons.
Infested trees are often located on private property. Gaining access to these sites can be difficult, either because the homeowner is away, or doesn’t want state or federal officials to enter their property. Gaining entrance can therefore take several months to arrange.
Until fairly recently, most official surveys have been made by inspecting the tree from the ground. Research has shown that a large percentage of infested trees go undetected when this method is used. It is difficult to see the early signs of an infestation, which may be just one egg niche. Infestations located near the top of the tree are hidden by foliage for much of the year. On cloudy or overcast days it is difficult to see the telltale signs of an infestation. Surveys are extremely labor-intensive and monotonous, and surveyor fatigue reduces efficiency.
It was found that significantly more infested trees were detected when tree climbers or hydraulic lift vehicles were used to allow surveys of the upper canopy to be made. Though this may be the preferred method of survey, it is expensive, and a large proportion of the trees in some infested areas are not easily accessible by this method.
The public has an important role to play in helping with ALB surveying. NYReleaf and the University of Vermont developed a brochure (The Citizen’s Guide to Beetle Busting, A Community Tree Survey for the Asian Longhorned Beetle) describing how homeowners can conduct a basic survey of the trees in their yards or on their streets. These brochures have been mailed out to all households within the infested areas of New York City.
Several research projects are underway to develop more effective survey and detection methods, including: pheromone traps to lure beetles and sonar equipment to detect beetle chewing noises within the tree. None of these novel tools are available currently.
The only hope for successful eradication of ALB will be long-term survey and detection. The ALB Science Advisory Panel recommended that surveys for ALB within known infested areas should continue for 5 years after the last beetle or infested tree is found. Considering the ever-changing demands on USDA and state agencies who are currently carrying out the surveys, it will take great discipline to adhere to this recommendation. If it is not however, the likelihood of achieving eradication will be slim.