In mid-summer, Extension IPM scouts and others throughout the state are busy hanging inconspicuous boxes in trees. These boxes are moth traps, equipped on the inside with sticky paper and pheromones to attract certain species of moths. The targeted moths are non-native species from Asia that could devastate forests if introduced to Alaska.
The caterpillar stage of these non-native moths are gluttonous feeders of leaves of a wide variety of trees, including larch, poplars, willow, birch and spruce. Defoliation leads to decreased growth and susceptibility to disease, and in extreme cases, infestations can even lead to death of large stands of trees and shrubs. In addition to complete defoliation in infested areas, the caterpillar silk and droppings, destroyed leaves and dead moths are a nuisance.
The Asian gypsy, rosy and nun and Siberian moths are all targets of these trapping efforts. Under the direction of the Alaska Division of Agriculture, traps are being set at locations where the moths are most likely to be found hitchhiking a ride to Alaska, such as RV parks and high-traffic shipping areas. Our goal is to detect the moths being accidentally brought to Alaska before they can establish and spread.
Asian gypsy moth adults and egg masses have been found in port towns and Interior Alaska at various times since the 1980s and as recently as 2014, but based on the numbers found and the length of time between detections, we do not think there are any overwintering populations. If trapping efforts were to detect established populations, an eradication program would quickly be put in place using the principles of early detection and rapid response to minimize management costs and damage to valuable forest resources.
In general, invasive species cause damage to natural resources, loss of recreation opportunities and decreases in property value. We are lucky that we still have some pristine environments free of invasive species in Alaska, but unfortunately that is changing. Anyone living in Fairbanks has observed the spread of invasive bird vetch along the roadsides. It is quickly overtaking the native plants that used to grow there, such as fireweed. And now an aquatic invasive plant, Elodea, is taking over the Chena Slough and spreading downstream into the Chena River and beyond.
In the case of Elodea, a local working group of various agencies is planning to eradicate the invasive plant in the Fairbanks area to keep it from spreading. Because Elodea is limited to a few water bodies in Interior Alaska, eradication is still feasible and action now will limit the loss of fish habitat and costs that would occur if we were to let it spread then decide later we need to manage it.
Bird vetch, the purple flowered vine, is much more widespread. Unfortunately, there is no working group attempting eradication or management on roadsides and public lands in the Fairbanks area, so it will keep spreading. The UAF Cooperative Extension Service publication “Control of Bird Vetch” can help you learn how to manage bird vetch on your property. Find it at http://bit.ly/akbirdvetch or contact your local Extension office for a copy.
Alaska is not immune to continued introductions of invasive species, but the outlook is not hopeless. You can be part of the solution by learning about invasive species and the changes they can cause, becoming an advocate for controlling them on public lands while the problem is still manageable — and doing your part by removing invasive species from your personal property.
Darcy Etcheverry is a program assistant with the University of Alaska Fairbanks Cooperative Extension Service agriculture and pest management program in Fairbanks. She can be reached at 474-2422 or firstname.lastname@example.org.