Stink bugs emit a foul smell when threatened.
Insects swarm lights at a tennis court in Miyazaki City.
On social media, one poster said the critters had invaded their terrace. Another said about 10 were found in their bathroom.
Insecticides sold out
Shelves for insecticides are now empty at one home improvement store in Mito City, Ibaraki Prefecture.
The store said sales of insecticides at all of its outlets is up more than 10-fold over the same period last year. The store is recommending customers use other products that also work against stink bugs.
Store official Kikuchi Daiki said there was previously never a need to set up a special sales section for insecticides for stink bugs, but they may need one this year.
According to an expert, last year's warm winter and abundance of food resulted in a mass generation of the bugs.
Arai Tomonori of the National Agriculture and Food Research Organization said there was an outbreak last year of stink bugs that eat cedar nuts and Japanese cypress nuts. They lived through the winter and began taking to the air in the spring.
Crop damage
Stink bugs are damaging farms in many areas.
One peach farm uses insect nets to shield its fruits. But this year, about half of them were damaged by stink bugs.
Stink bugs emit substances, including aldehyde, that cause skin irritation. Dermatologists warn against touching them.
How to trap stink bugs
Professor Shintani Yoshinori of the Minami Kyushu University recommends people use insecticides as well as plastic bottles to trap the bugs.
He said a plastic bottle, cut in half, can be used to capture the critters.
This video shows how to trap stink bugs with a plastic bottle.