The theft of iPhones and iPads is so widespread it’s known as “Apple picking.”

But Apple devices aren’t the only targets. Nearly one in three robberies nationwide involves the theft of a mobile phone, according to the Federal Communications Commission. The problem is so severe in their cities that San Francisco District Attorney George Gascon and New York Attorney General Eric Schneiderman this summer convened a “smartphone summit” to urge the industry to implement technological solutions to thwart the robberies.

Now some makers of wireless mobile devices, notably Apple Inc. and Samsung Electronics Co., are taking steps to fight back against the thieves.

Apple’s new iOS 7 mobile operating system includes a security feature called Activation Lock that automatically works with the free Find My iPhone feature. Find My iPhone is built into iOS 7 and can be enabled in Settings.

Activation Lock basically ties your devices to your Apple ID. Criminals who steal phones typically “wipe” the devices clean so they can resell them. Now any thief who wants to turn off Find My iPhone, erase the device or reset the device will be required to enter the Apple ID and password.

Supporters of such security measures say they will discourage thieves from stealing phones because they will not be able to sell them.

Alex Castro, who lives in Oakland, Calif., started spreading the word about Activation Lock as a community service as soon as it came out in October.

“A friend’s cousin was killed for her iPhone in St. Louis,” said Castro, 39. “My goal is to educate others. I had no idea that there was such a black market for smartphones.”

Castro notes that Activation Lock won’t stop someone from robbing you for your phone. But it will discourage thefts, he says, by making stolen phones “nearly worthless.”

“This has the potential to decimate the market for stolen iPhones, and if there is no demand, then there will be no reason for criminals to mug people for their iPhone,” he wrote in Oakland Local, a popular blog.

Samsung’s Galaxy S4 smartphone includes software that allows owners to remotely delete files and lock down the device.