“This time they got caught” was the distinct overtone in a recent news story in which 15 illegal immigrants from China who had packed themselves into a crate were found just in the nick of time by an alert border inspector. The fact that this was news, and that the successful inspector was described as being ultra sharp, amounted to a tacit acknowledgment that many other crates full of warm-blooded, dog-sniffable cargo slip through the border undetected.
This, of course, led me to think about insects. If it’s difficult to prevent unapproved humans from entering the country, the odds against keeping out tiny arthropods, as well as fungi and seeds, must be sky-high. There are thousands of different plant and animal species that are perfectly well mannered in their established habitats in Europe and Asia but multiply out of control when transported to new environs. No wonder they all want to come here!
Already, North American forests have been forever changed by chestnut blight, beech bark disease, Dutch elm disease, gypsy moth, and hemlock woolly adelgid. But in the Northeast, these introduced pests may seem relatively minor if nothing is done about two menacing newcomers, the Asian longhorned beetle (ALB) and emerald ash borer, both of which slipped in and became well established before being identified. The ALB has several of our most common and valuable trees on its menu: maples, birches, and ashes. Though the emerald ash borer feeds only on ash, it is estimated that 10 million ash trees have been killed by this cambium-feeding beetle in the short time since its detection in 2002. In spite of intensive efforts to control its spread, its range continues to increase.
The ALB, in contrast, exists in smaller numbers, and the adults don’t fly as far as far as the ash borers do. Despite a massive campaign that has involved felling and chipping more than 10,000 trees, it has been found in new areas beyond the original infestation and has steadily expanded its range in the greater New York City metro area.
Both of these insects are thought to have been in the U.S. for many years before they were identified. In that time, their populations became so well established that eradication now seems a distant hope. The rapid globalization of the economies of nearly all countries has increased the problem enormously.
Recent changes at the federal level have left the border less well protected than it was when the ALB and the emerald ash borer arrived. In 2002, as part of the “one face at the border” initiative, about 2,680 inspectors from the Agricultural Plant Health Inspection Service (APHIS) were transferred to the Homeland Security Bureau of Customs. Some of these inspectors will be agricultural specialists, but in many cases, initial inspections are now made by former customs officials who have had only 12 to 15 hours of instruction in agricultural pests – compared to the science background and nine-week course that APHIS used to require. Under the current system, the trained inspectors working at the border have to balance the need to look for insects and diseases with the need to look for explosive devices, drugs, and other contraband, including people. Because the border is far and away the best place to stop these pests, and their potential economic impact is so enormous, whatever funds are expended will be well spent.
Though the border situation looks dire, there are signs of hope. Several small, accidental introductions that were caught early may have been eliminated or at least controlled. In Chicago, where the ALB was quickly found and targeted, officials have been able to reduce the quarantine area, and the beetle might even have been eliminated there. Similarly, emerald ash borers in a shipment of trees to the East Coast from Michigan were discovered, and dealt with. There are other examples.
The Forest Service has swung into gear, and systems are being developed that allow analysis of the particular hazard level at various entry points, each with its own set of activities and cargo. These should improve the chances of finding an insect or disease before it gets out of hand.
Perhaps the most useful tool of all would be a better-informed, sharp-eyed populace. With many eyes on the lookout, early detection of menacing insects will be far more likely. The website www.invasivespecies.gov has information about all things invasive. For details on just the ALB, see www.uvm.edu/albeetle.