In August, the Asian longhorned beetle (ALB) was discovered in Worcester, Massachusetts, by an astute resident. The city quickly mobilized; today, a 62-square-mile quarantine zone stretches around the known infected trees. To date, nearly 1,700 infected trees have been marked for removal within this zone. The number continues to rise, as does the anticipated price tag ($24 million and headed north).
A U.S. Department of Agriculture, Animal and Plant Health Inspection Service (USDA-APHIS) task force is still trying to gauge the extent of the infestation. U.S. Forest Service smokejumpers have been pulled off western wildfires to assist in the tree climbing work. In nearby woods, undergraduates, entomologists, and concerned citizens from around the Northeast are forming patrols in hopes of containing the insect before it breaks out into the Northern Forest.
The majority of the trees that have been flagged so far are on private land. Landowners are receiving form letters that read: “Unfortunately, our professional survey and subsequent analysis confirmed one or more infested trees on your property that must be removed by and through the regulatory authority of the Commonwealth of Massachusetts.”
Local tree crews are poised to begin cutting at the first hard frost. The trees will fall and then be chipped or burned. Where possible, stumps will be ground to a minimum of 9 inches below grade. Where this is not possible, stumps will be treated with the herbicide triclopyr to eliminate re-growth.
According to the USDA’s eradication plan, every host tree within a half-mile radius of an infected tree will receive trunk and/or soil injections of imidacloprid, an insecticide. These injections will take place in early spring. The direct injection method is designed to limit pesticide exposure to people and animals, particularly honey bees, which are susceptible to low concentrations of imidacloprid.
Things get more complicated in wooded areas. While the quarantine area is largely urban, it does contain forest land, including 1,500 acres of conserved forest. Volunteers, working in conjunction with the Greater Worcester Land Trust, are scouring the area’s forests for signs of the bugs. In these wooded areas, because of greater tree density, it has been proposed that every host tree within an eighth of a mile of an infected tree should be destroyed.
According to Suzanne Bond, spokeswoman for USDA – APHIS, the ALB probably showed up in Worchester about 8 to 10 years ago in a shipping pallet from China. Not on board the pallet, but in the wood itself. Poplar is often planted in rural Asia as an agricultural windbreak; it’s also a common host tree for the ALB. When these poplar trees are harvested and turned into low-grade lumber, the manufactured pallet can contain beetle eggs and larvae.
Asian longhorned beetles decimate trees. Spectacularly. A female can inject a single tree with up to 70 individual eggs, which hatch into larvae that burrow into the tree’s trunk. After spending the winter feeding, the larvae pupate and emerge from the tree as adult beetles, who then go right to work feeding on the tree’s leaves and twigs. They’re homebodies, and an adult bettle will often deposit her eggs on the same tree in which she was born. As a result, even the healthiest host trees are quickly turned into Swiss cheese.
If there’s a silver lining in all this, it’s that the beetles’ size (up to an inch and a half long) and stay-at-home nature make for a relatively slow-moving infestation. Left to its own devices, the beetle would spread slowly; unfortunately, people accelerate the process.
Despite ubiquitous local news coverage and a well-publicized federal order that forbids the moving of firewood, woody debris, lumber, and nursery stock from the quarantined area, there have already been at least two reported cases of infected firewood leaving the quarantine zone.
Bond said that it’s people who are causing the problem by moving infested wood. “That’s how this bug gets spread – by people,” said Bond.
To underscore how serious this problem could be, the USDA estimates that if every urban area in the continental US were to become infested with ALB, 1.2 billion trees would die.