Stink bugs are back — and in greater numbers than recent years

They are pests in the truest sense of the word, and they are back.

They are brown marmorated stink bugs and people love to hate them because of their annoying habit of invading homes and gardens. They have earned their name from the odor they produce from the glands on their abdomen.

That apparently only happens when they’re threatened, but they must feel threatened a lot because they sure have a way of stinking up a place in a hurry.

The stink bug is native to China, Japan, Taiwan and South Korea and first showed up in Pennsylvania in 1998. While their numbers a decade ago were much worse than anything now being experienced, their ranks have been growing in recent years.

And why is that happening?

According to Dave Vargo, owner of Kiski Garden Center, part of the cause has to do with the warmer than usual winter the region experienced.

“The warmer winter allowed them to build their population back up again,” he said. “The problem this time of year is they’re looking for a place for the winter. If there are a bunch of them gathered on the side of your house or a window sill, the best thing to do is spray an insecticide with pyrethrum directly on them.”

However, Penn State research professor and tree fruit extension entomologist Greg Krawczyk said there is a big misconception about stink bugs.

“They are annoying. They are a nuisance, however, they don’t bite, they don’t feed when they are inside the house, they don’t reproduce when they are inside the house. They’re just looking for shelter,” he said. “It’s completely natural. They have to find shelter to survive the winter.”

Krawczyk compares it to bears hibernating. He also said the number of stink bugs being seen these days is nowhere near the numbers seen a decade ago.

“We had reports from people who were counting 20 to 30,000 of them. But now the numbers are much lower because they’ve been here long enough and some of the biological control agents are gradually taking control of them,” he said. “We’ll never eliminate them, but the numbers are much more tolerable.”

Vargo said it’s too late in the year to trap the stink bugs. The spring mating season would have been the time to do that.

“People don’t think to put them out in the spring because they’re not a nuisance (then).”

Krawczyk agreed the stink bugs are nearly impossible to get rid of this time of year. He compared them to hotel guests in no hurry to check out.

“People can spray their houses with insecticide, but that’s not an option that most people like,” he said. “There’s no way to attract them away from houses and there’s no way to attract them when they’re in the house. They don’t respond to anything because they are not interested in food, they are not interested in light.”

Krawczyk said the only thing people can do for now is wait until spring when the stink bugs will want to be outside again. In the meantime, they will find places to hide because they don’t want to see people any more than people want to see them.