Less than a decade after it was first identified in California, an invasive insect called the glassy-winged sharpshooter had turned the bacteria that causes Pierce’s from a nuisance into a nightmare. The elongated beetle, with wings like red-tinted stained glass, is faster and flies farther than snipers native to the state, and it can feed on tougher vines. Its arrival, which the state believes was in the late 1980s, has accelerated the spread of the disease.
RODRIGO KRUGNER/USDA-ARS
Inspections and targeted pesticide spraying have allowed the state to largely limit invasive sharpshooting to Southern California. But the disease is still incurable and threatens to get worse and more difficult to combat due to climate change.
Researchers are now trying to add advanced technology to California’s anti-Pierce arsenal by altering the glassy-winged sharpshooter’s genome so that it can no longer spread the bacteria.
Such a solution is possible thanks to CRISPR gene editing technology, which has made it increasingly easy to edit the genes of any organism. The technique has been used in experiments in cancer immunotherapy, apple breeding and – controversially – human embryos. Now a growing number of researchers are applying it to agricultural pests, aiming to control a range of insects that collectively destroy approximately 40% of global crop production per year. If successful, these efforts could reduce reliance on insecticides and provide an alternative to crop genetic modifications.
For now, these genetically modified insects are locked up in labs around the world, but that’s about to change. An American company expects to start operations this year greenhouse testing in collaboration with the United States Department of Agriculture (USDA) from fruit-damaging insects rendered sterile using CRISPR. At the same time, scientists from the government and private institutions are beginning to learn more about the genetics of pests and are editing more species.
The use of genetically modified organisms remains controversial, and processed agricultural pests have not yet been approved for widespread release in the US. A potentially lengthy and still evolving regulatory process awaits. But scientists say CRISPR has marked a critical juncture for using insect gene edits to impact agriculture, with more discoveries to come.
“Until CRISPR, the technology just wasn’t there,” said Peter Atkinson, an entomologist at the University of California, Riverside, who works on adapting the sharpshooter. “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 glassy-winged sharpshooter until recently. The first draft of its genome was mapped in 2016 by a group at the USDA and Baylor College of Medicine in Texas. But the map had gaps. In 2021, researchers at UC Riverside, including Atkinson, filled in many to find a more complete version.