Natural Predator May Be Answer To Stopping Stink Bugs

BALTIMORE (WJZ) — Looking for a natural born killer to go after a foreign invader. The target is the Asian stink bug, which has been crawling inside Maryland homes all winter.

Alex DeMetrick reports researchers have found a natural predator for the pests, but don’t know if it’s safe to let loose.

In the U.S., no poison can kill it. There’s no predator to hunt it.

“They’ve been a very successful invader,” said Dr. Kim Hoelmer, USDA researcher.

Most likely brought here in a shipping container from Asia five years ago, the brown marmorated stink bug has spread throughout the Mid-Atlantic.

In Maryland, they have spent the winter making themselves at home in our homes. But as spring warms, they will migrate back outdoors and multiply.

“Some entomologists have been quoted to say it’s going to be biblical,” said Paula Shrewsbury, University of Maryland.

That’s bad news for growers, who saw crops like apples damaged last year.

“We’ve had apple growers in Maryland, Virginia and West Virginia that have lost 80 percent of their crop due to this,” said Shrewsbury.

Leaving marks where they feed, more stink bugs will mean more losses, because in the U.S. nothing feeds on them.

“I’m nervous. I’ll pray for some answers, and there are smart people working on this,” said Dwight Baugher, Carroll County grower.

This is where some of them are working: a USDA research lab in Delaware.

“All of these small petri dishes contain egg masses of the stink bug, which we have taken from our colony of egg masses,” said Hoelmer.

Those egg masses are the stink bug’s weak spot. Deposited in clutches of 24 eggs on leaves, they are vulnerable to a natural predator not much bigger than ground pepper–a tiny wasp from Asia that implants its own young in stink bug eggs.

“And as that egg hatches and grows, it consumes the egg from the inside out. So instead of an egg producing a healthy young stink bug, it produces another wasp,” said Hoelmer.

But they can’t let it out of the lab, not yet.

Under tight control, the wasps are being studied to see if they’ll attack native stink bugs.

“There are some stink bugs in North America that are beneficial because they’re predators, important agricultural predators. So we want to make sure we’re not introducing a new natural enemy to a beneficial stink bug,” said Hoelmer.

Determining if the wasps will do more good than harm is going to take the lab time.

“Probably two years or so from now, we may be ready…if we find an agent we think is safe to release,” said Hoelmer.

Meanwhile, an invader is spreading unchecked.

Because of the serious threat they pose to agriculture, researchers are working on other biological controls, as well as racing to develop an effective pesticide against stink bugs.

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