One thing Japan has is old, sometimes hot and rainy, densely populated cities and one thing old, sometimes hot and rainy densely populated cities have is roaches. So, while looking for investment data on Japan, I stumbled across an article
translated by Wendy Imura from Yuki Wada's original. It has the following tips (in addition to the obvious point of not leaving out boxes of pizza or beer bottles, keeping doors and windows closed, and sealing any cracks):
1. Keep potted plants or flowers outside.
2. Keep furniture 1" from the wall and use plastic instead of cardboard boxes to deny them nesting grounds
3. Adhesive traps are safe and cheap, but move them around (http://tinyurl.com/pglqu) are recommended.
4. Boric acid traps can be made out
of boric acid, flour, oil, and onions. I've always heard cocoa and boric acid.
5. Spraying roaches and then smashing them works pretty well. But why use roach spray when "kitchen cleaners, toilet cleaners, mold removers, and antibacterial sprays are all more handy, cheaper, and more effective,"
6. Roaches can be ambushed from the front, not from the rear, since they have wind sensors in the back.
7. Do not vacuum up cockroaches in the vacuumcleaner, since "sometimes female roaches can actually breed when they die, turning your vacuum cleaner into a mobile roach nest."