Forest Pests
Warming and drought fuel beetle infestations, that devastate forests
Warming temperatures and droughts are fueling the expansion of pine, mountain and spruce beetle outbreaks across North America, Europe, and Siberia, ravaging tens of thousands of square miles of woodlands. Scientists warn that some forest ecosystems may never recover.
What is the problem? Various pests are currently damaging our forests, including both invasive species like the emerald ash borer and native pests such as bark beetles. Notable culprits include the emerald ash borer (EAB), hemlock woolly adelgid, gold-spotted borer, and bark beetles, among others.
Entire Forests are Dying
Identifying the Emerald Ash Borer
Current Solution Status
Invasive Species Corporation (ISC) has identified two candidate microbes as potential solutions for a wide range of forest pests. Efficacy testing is underway against beetles, borers, spotted lanternflies, woolly adelgids, and other destructive species. Once efficacy is demonstrated, ISC will simultaneously advance manufacturing and application methodologies to scale the solution for widespread use.
Extent and Impact of Infestation
Bark beetles are among the most destructive pests affecting forests worldwide. Over the past 20 years, massive infestations—particularly mountain pine bark beetles—have decimated millions of acres of conifer forests from New Mexico to British Columbia.
Other major threats include the southern pine beetle in North America, the spruce ips in Europe, and the coffee berry borer, which damages coffee plantations globally.
“The level of conifer mortality we’re seeing in North America and Europe is historically unprecedented,” says Jesse Morris, a geographer at the University of Utah. Scientists warn that climate change is driving increasingly severe outbreaks, leading to intensified wildfires, disrupted watersheds, habitat destruction, and reduced carbon storage.
Rising temperatures prevent the widespread winter die-off of beetle larvae, allowing populations to explode. These pests are expanding into new regions, reproducing more frequently, and rapidly overwhelming forests. In some areas, beetle infestations have become so severe that once trees are wiped out, they even begin attacking telephone poles.
The Emerald Ash Borer Crisis
Ash trees, among North America’s most valuable and abundant woodland species, are under siege from the emerald ash borer (EAB). This invasive beetle has destroyed 40 million ash trees in Michigan alone and hundreds of millions across the U.S. and Canada. As of 2018, EAB infestations were confirmed in 35 states and five Canadian provinces, with the potential to spread even further.
The loss of ash trees carries devastating ecological and economic consequences. Ash species provide critical habitat, contribute to nutrient cycling, and stabilize waterways. Their destruction has resulted in billions of dollars in projected treatment and removal costs. Urban and suburban areas have been particularly hard hit, with municipalities facing soaring water usage, increased stormwater runoff, and diminished property values.
Black ash, a species deeply rooted in Indigenous cultural traditions, is especially vulnerable to EAB infestations. Many Native American and First Nations tribes rely on black ash for traditional basketry, and some trace their origins to the tree itself. In response, collaborative efforts are underway to collect and preserve ash seeds before the species faces widespread extinction.
Without effective intervention, the cascading effects of these pest outbreaks will continue to reshape ecosystems, disrupt industries, and threaten biodiversity on a global scale.
Current Management
Infested trees are either removed or treated with insecticides. Research indicates that insecticide treatments are most effective on ash trees with less than 50% canopy thinning. Trees with greater than 50% canopy loss are generally beyond treatment and should be removed.
Four active ingredients are used to control emerald ash borer (EAB): imidacloprid, dinotefuran, emamectin benzoate, and azadirachtin. Among these, imidacloprid is the most cost-effective and easiest to apply.
Biological Control
To combat EAB, three species of stingless wasps are being introduced across Indiana and the U.S. These wasps, natural predators of EAB in Asia, help reduce beetle populations but are unlikely to eliminate the pest entirely. Extensive testing ensures they do not threaten native insect species. While more wasps are being reared annually, their release is carefully managed by professionals to maximize effectiveness.
This Tiny Beetle Is Devastating Forests in the Worst Outbreak Ever
