The emerald ash borer (Agrilus planipennis) is a metallic green beetle from Asia that is wiping out trees across the eastern US. First detected in Michigan in 2002, the pest is spreading rapidly and has killed billions of ash trees, with seven out of nine ash trees in North America threatened by this newcomer.

tree in eastern US

This is only the latest in a litany of exotics to ravage American forests. Sixty-two high-impact insect species and a dozen pathogens have arrived since the 1600′s. Only two were detected before 1860.

 The emerald ash borer

The emerald ash borer. Image; Wikimedia Commons

Increased global trade and travel, along with climate change and warmer winters, are all fueling the problem. And the devastation has pushed scientists and foresters to look towards biotechnology for a remedy.

‘Almost every day there appears to be a new forest pest and some of these are quite devastating,’ says tree geneticist Jeanne Romero-Severson at the University of Notre Dame, Indiana, US. 

‘Biotech approaches such as transgenic technology and CRISPR gene editing could be valuable tools in saving specific species.’


These biotech solutions look sexier to funders, and policymakers, and that is where the resources go. But in many ways, it is a dead end if you don’t have a foundational breeding programme to feed into,’ warns DiFazio, a plant geneticist at West Virginia University, US.

A technology like CRISPR for gene editing is fast and powerful, but mostly it is used in lab organisms where much is known about their genetics. Without deep knowledge of a tree’s genome, CRISPR will be far less useful.


CRISPR is a gene editing tool that first came to prominence in the 1990′s and is considered one of the most disruptive technologies in modern medicine.

Powell, a plant scientist at the State University of New York (SUNY), US acknowledges that ‘the biggest thing is to the get the public onboard; a lot of people are afraid of genetic engineering. 

Surveys suggest that knowledge about genetic engineering technology, as well as about threats to forest health, is fairly low amongst the general public. Given these deficits, ‘public opinion might be vulnerable to changes,’ notes Delborne.