OKLAHOMA CITY - Putnam City High School's baseball fields were shut down Wednesday after a swarm of bees attacked the grounds crew. The school says the fields are safe tonight, experts warn Oklahoma residents not to let our guards down this summer.

Don't mess with a bee and it won't bother you, right? Experts at Oklahoma State University say that's usually true, unless you run into a swarm of "Africanized Honeybees" also known as "Killer Bees". They look almost identical to a regular honeybee, but experts say they're slightly smaller than their European cousins.

It's true their stings can be deadly in high doses, but experts say the killer bees venom is not any stronger than the average European honeybee; it's their method of attack that's six times more aggressive than a regular honeybee swarm.

A killer bee swarm aims to do some damage and is known to attack whoever or whatever disturbed their hive or queen.

"Saw the swarm, swarm around the practice mound," said Putnam City North Grounds and Field Director, Steven Turner.

Turner has been stung by a bee before, but says what was swarming around the crew on the high school ball fields on Tuesday was something he's never seen before.

"In the air alone was probably 100 bees," Turner said.

Turner says spraying the bees, just made them mad.

"Jimmy was stung 5 or 6 times. I was stung 10 or 12 times," said Turner.

They called the school exterminator and when they lifted the practice mound, that swarm grew to about 200 and 250 angry bees.

"We were surprised by how many there were," he said.

The crew is glad all of the school kids, families, players and coaches weren't there yet for baseball and softball. It was Senior Night on Tuesday, but the district decided it wasn't safe and shut down the fields.

"They took action. They controlled the problem," OSU Entomology & Plant Pathology Department Head, Dr. Phillip Mulder said.

Mulder says that was the right call because the bees attacking the crew were probably Africanized Honeybees.

"It's pretty likely [they were Africanized]," Dr. Mulder said. "We know what counties, so when we get a report, we consider that county infested."

The grounds crew sent some dead bees to OSU extension for testing, but Mulder said they may not be able to tell if they are killer bees or not because of the chemicals left in the bees after they killed the swarm. Mulder says so called killer bees haven't killed a human being in Oklahoma. However, since they arrived in the Sooner State in 2004, they have killed pets

"They operate as one, so several hundred will sting you," said Mulder.

The hive at Putman City High is gone and fields are now open for games.

Experts at OSU want families to watch out for any bee swarm this summer, not just killer bees. Mulder says a human can survive being stung hundreds of times by bees, but if a person is allergic to bees, one sting to the head or neck area can be deadly.

Killer Bees have been known to make their home inside old tires or water meters. And bothering them could be as innocent as doing yard work. The Africanized Bees don't like the noise weed whackers or lawn equipment make so they may come out to inspect.