The two boys rode with their dad into work over the summer, noticing that as their car pushed deeper into a western pocket of Southeastern Pennsylvania, they saw one spotted lanternfly after another.

They zealously squashed the invasive insects, then talked about it for the rest of the day.

Greyson, 13, and Nolan, 7, challenged their tech-savvy father, Brad Line, to create an app, one all about squashing the bug — and to make it fun.

Line, 47, was skeptical. But his sons were persistent. They were sure that hundreds of people would use the app if it was formatted like a game that ranked who squashed the most lanternflies. The colorful, winged insect native to Bangladesh, China, India, and Vietnam has proven its ability to cripple Pennsylvania’s $18 billion grape, lumber, and landscape industries.

“OK, fine, we’ll do this," Line, an information-technology director, told his sons. "Maybe a few people will download it.”

So they created Squishr.

The idea of the app is simple.

Kill a lanternfly. Take photographic evidence with the app, post it, and repeat the process. The most avid participants can find themselves on the leaderboard, billed as “Today’s Top Squishers." Users can post a location of a lanternfly kill to a map that others can see.

Over a month-and-a-half, Line designed the app and a developer in Pakistan produced it. Line submitted Squishr to Apple on Friday night and woke the next morning at his Villanova home to see it had been released on the App Store. By the end of the day, 130 people had signed up. The next day, 160 more.

His kids were thrilled.

Harriet Campbell, arguably the app’s most prolific user, wielded one of her 12 fly swatters to kill 192 lanternflies on Saturday. She photographed each one. Her username: "swat team.”

» READ MORE: Philly cops: Please don’t call 911 to report spotted lantern fly invasions

Campbell is not a newcomer to vanquishing spotted lanternflies. And she joins her neighbors, who, like her, stroll about their balconies on the hunt for the bug. (“We kind of wave our fly swatters at each other and say hello," she said.)

“In the last 2½ weeks I’ve squished — I’ve put them all in a bucket marked ‘Squished’ — six quarts of them,” said Campbell, a 64-year-old retiree in Plymouth Meeting. “I’m a little obsessed with them, and I’m retired, so you put those two things together and I can spend all day out here patrolling my balcony.”

The more people join from states invaded by spotted lanternflies, the more robust data the app can collect on the insect, said Line, a graduate of the Wharton School of the University of Pennsylvania. He has contacted the Department of Agriculture in Pennsylvania, New Jersey, Maryland, Delaware, and Virginia with offers to share data on the bug’s path on the East Coast. Pennsylvania and Maryland’s Department of Agriculture said it would soon start to accept Squishr’s data, he said.

“The farthest west and south is Kennett Square," Line said Monday, scanning the map that tracks where lanternflies have been spotted. “The farthest north is near the Allentown area now, and the farthest east is in Center City in Philadelphia."

The lanternfly has spread to 14 counties — which are now held to stringent quarantine standards to ensure the bug does not travel farther west — since it was first spotted in 2014.

It has since migrated from Berks County, where it was first discovered, to Schuylkill County. Philadelphia and its suburbs have not been spared, with clusters of the bugs clinging to trees, buildings, cars, and sidewalks. Surrounding states, too, have grappled with the invasion. In Pennsylvania, people who purposely spread the lanternfly invasion can face criminal charges or civil penalties.

In the five years since the lanternfly was detected in the state, the Pennsylvania Department of Agriculture has established a hotline to report sightings of the bug. It has asked residents to be on the lookout, ready with a well-timed stomp of the shoe or — for some — a smack of the fly swatter.

Line just wants to document it all. His free, no-frills app is a blend of niche entomology, a call to civic duty (“Kill it! Squash it, smash it ... just get rid of it,” the Pennsylvania Department of Agriculture has said of the spotted lanternfly), and lighthearted — but goal-oriented — competition.

“I’m not looking to make a penny for it,” Line said. “It’s just for fun, and just to fight this thing.”