In the upper reaches of Nova Scotia’s tallest trees, a minuscule black speck, no larger than a grain of sugar, is causing significant damage. The hemlock woolly adelgid, an invasive insect detected in the province in 2017, is swiftly spreading through Nova Scotia’s hemlock forests, resulting in desolate, ghostly trees. By extracting sap from the bases of hemlock needles, the adelgid can fatally harm a tree in less than ten years, leaving behind a white, wool-like substance that gives the insect its name.
At Acadia University’s campus, researchers are actively investigating solutions to combat this threat. Led by Acadia, a research project is evaluating the effectiveness of insecticidal treatments utilized to manage the hemlock woolly adelgid. Additionally, they are establishing a biological control facility to regulate adelgid populations.
Expressing the critical nature of the situation, Kirk Hillier, a biology professor and the project’s lead researcher, stressed the urgency in addressing the issue. Witnessing the impact of dead trees firsthand, Hillier emphasized the significant threat posed by the adelgid.
The research project focuses on two key aspects. Firstly, it aims to assess the effects of adelgid infestation on biodiversity and the implications of insecticides. Currently, hemlocks are treated with two types of insecticide, either through injection into the tree or spraying on the bark, to safeguard tree survival. Despite potential impacts on pollinators, the necessity of using insecticides to prevent the loss of hemlocks in Nova Scotia is paramount.
To gauge the environmental impact, researchers will monitor changes in biodiversity by trapping insects and birds in infested areas. They will also study the effects of insecticides on ground-nesting bees through lab experiments.
One challenge with insecticides is their high cost and labor-intensive application process. To streamline treatment efforts, the project is testing funnel-shaped traps equipped with molecular tools to detect adelgid presence at early stages. By detecting DNA traces from the insects, these traps can provide early warnings, enabling prompt action to protect hemlocks.
In the long term, traps will aid in identifying natural predators of the hemlock woolly adelgid, such as Laricobius nigrinus, a black beetle. The Canadian Forest Service has released thousands of these beetles in Nova Scotia since 2023 to combat the adelgid infestation. Acadia researchers plan to expand these efforts by establishing a biocontrol facility on campus.
The envisioned biocontrol facility will serve as a rearing and testing ground for various predator species, including the silver fly from British Columbia. By developing a sustainable biocontrol program, researchers aim to release tens of thousands of predators annually to manage the adelgid infestation without relying on insecticides.
Recognizing the critical need for long-term funding to sustain biocontrol efforts, forest ecologist Donna Crossland emphasized the importance of government support to ensure the program’s continuity. She stressed the moral obligation to conserve Nova Scotia’s hemlocks, highlighting the urgency of implementing effective control measures to prevent irreversible tree loss.
With a sense of urgency, Hillier emphasized the importance of public awareness and securing operational funding for a biocontrol program. Delay in establishing this program may result in irreversible tree loss, underscoring the immediate threat faced by Nova Scotia’s hemlocks.
Ultimately, the project’s goal is to preserve the hemlocks for future generations by implementing sustainable and effective control measures against the hemlock woolly adelgid infestation.