Genetically modified moths pass greenhouse testing, ready for the wild

A team of researchers at British company Oxitec has developed a genetic approach to controlling diamondback moth caterpillars and report that trials in greenhouse conditions has gone so well that they are ready to conduct tests in the wild. 

Diamondback moth caterpillars are one of the world's worst insect pests—they eat holes in the leaves of kale, cabbage, canola, broccoli and cauliflower, killing the plants and causing billions in dollars of losses for farmers around the world each year.

Efforts to curb them have been mixed and the caterpillars appear to be winning—they have developed immunity to most chemicals applied to kill them. For that reason scientists have looked to other ways to tackle the problem, one of which is genetic modification. The team at Oxitec, has come up with a way to cause female offspring of the moths that parent the caterpillars to die before they can reproduce, slowly causing a drop in population when they are released into a native group.

In coming up with their self-limiting gene approach the team added another piece of usefulness—an off switch. The gene only self-limits in the absence of tetracycline, such as when the moth is out in the wild. To grow a community of the moths, the team need only feed them food with the chemical added.

They note that their technique allows for targeting just diamondback moths, thus other insects would not be harmed—and neither would birds or other animals if they eat the moths or caterpillars.