Less than a decade after it was first identified in California, an invasive insect called the glass-winged sniper had turned the bacterium that causes Pierce from a nuisance into a nightmare. The elongated beetle with wings like red-tinted glass is faster and farther than the state’s native snipers, and it can feed on tougher vines. His arrival, which the state suspects was in his late 80s, accelerated the spread of the disease.
Through inspections and targeted spraying of pesticides, the state was able to largely confine the invasive sniper to Southern California. But the disease still has no cure, and it threatens to worsen and become harder to control due to climate change.
Researchers are now attempting to add cutting-edge technology to the arsenal of California’s anti-pierce arsenal by altering the genome of the glassy-winged sniper so that it can no longer spread the bacterium.
Such a solution is possible thanks to CRISPR gene editing technology, which has made it increasingly easy to modify the genes of any organism. The technique has been used in experiments on cancer immunotherapy, apple breeding and – controversially – with human embryos. Now a growing number of researchers are applying it to agricultural pests to control a range of insects that collectively destroy about 40% of the world’s crop production each year. If successful, these efforts could reduce dependence on insecticides and provide an alternative to genetic modification in crops.
Currently, these genetically engineered insects are being confined in labs around the world, but that’s about to change. This year, a U.S. company, in partnership with the U.S. Department of Agriculture (USDA), plans to begin greenhouse testing of fruit-damaging insects sterilized with CRISPR. At the same time, scientists in government and private institutions are beginning to learn more about pest genetics and make changes to more species.
The use of genetically modified organisms remains controversial, and engineered agricultural pests have not yet been approved for widespread release in the US. A potentially lengthy and evolving regulatory process is ahead. But scientists say CRISPR has heralded a critical moment for the use of insect gene modifications that impact agriculture, and more discoveries are on the horizon.
“Until CRISPR, the technology just wasn’t there,” says Peter Atkinson, an entomologist at the University of California, Riverside who is working on modifying the sniper. “We are entering this new era where genetic control can be realistically considered.”
Know your enemy
Scientists didn’t know much about the genetics of the glass-winged sniper until recently. The first draft of its genome was mapped in 2016 by a group from the USDA and Baylor College of Medicine in Texas. But the map had gaps. In 2021, UC Riverside researchers, including Atkinson, filled in many of them to create a more complete version.