The hot weather brings out some monstrous bugs. There are some pretty big bees, cockroaches, and centipedes, as well as the usual annoying ants, spiders, mosquitoes, and small flies. The best way to avoid an encounter with insects is to keep your house clean. Try not to leave dirty dishes around and clean up food crumbs immediately. In addition, putting food trash in your freezer instead of your trash can is a good way to get rid of both the odor and the bugs.
Though they look like evil demons, almost all of the bugs in Japan are harmless. Just trap them in a cup and take them outside.
There is, however, one insect to look out for – the infamous Mukade‘ (百足). Mukade are a poisonous type of centipede, with a bite somewhat like a bee sting. If you are bit, wash the bite with soap and warm water. If it becomes swollen, go the hospital immediately. Mukade don’t like the heat or the rain, so the hotter and wetter it is, the more likely they are to find their way into your cool, dry abode. To prevent this from happening, spray/dust insecticide around the base of your house, especially doors and other thresholds, every two weeks or so (more often if it rains.) Insecticide can be found at most hardware or grocery stores, and sells for ￥500-800/bottle. If you can’t read Japanese, just look for a picture of a Mukade on the bottle.
Insecticides can come in a spray bottle , powder bottle or traps. It is recommended you leave the powder around doorways (front door & balcony doors) and that you spray wall openings / leave traps(caps) near holes (anyplace you think a Mukade can enter).
Insecticides which are effective against Mukade often also referred to as “虫コロリアース”
The gokiburi is a type of large cockroach. They move very fast and catching (or killing) them can be quite difficult. Pouring a pot of boiling water on them is the best way to kill them (put a cup or bucket over the demon while you go boil water.) Or, you can buy a spray at the drugstore that will kill them by freezing them. Look for the picture on the spray can.
If you want to do some prevention, you can buy roach motels and do-it-yourself fumigation kits. The latest fumigators work in a couple of hours, but be careful because they contain harmful agents. Do not step on the spray. Make sure that you store food and commonly used household items well away from the area that you’re fumigating. Also make sure that any cookware, utensils, clothes, or anything else that you use regularly, is thoroughly washed if it came into contact with chemicals. The instructions are quite complex, so always ask someone to help you if you don’t know what you are doing.
If you feel uncomfortable with chemical insecticides, you can find at large stores like Loft or Tokyu Hands a spray with a herbal scent that repels insects. Spray all around the windows and doors, under the refrigerator and behind other furniture, and all around the base of your house. I have found these sprays quite helpful.
Gokuburi Spray (referred to as GokiJet (ゴキジェット)
The dani is a kind of small mite that likes to live in tatami mats. If you wake up with itchy bites on arms and legs that don’t quite seem to be mosquito bites, dani are probably the culprit. You can buy a spray or sheet at the drugstore that is safe to spray/use on your tatami, futon, couch, etc, and will eradicate the dani from your home.
You can also get a “needle” variety to inject the spray inside your tatami mat
Other bugs/insects prevention methods
Indoor pyrethroid insect repellent to kill mosquitoes and fliesin your home and prevents more from coming in. Releases metered doses of the active ingredient after being switched on, so it cannot over-saturate the air. Only leave the device on for 12 hours per day, and switch off. Works even with the windows open.
Outdoor Transfluthrin and empenthrin insect repellent net to kill mosquitoes/flies outside your home and prevent them from coming inside.
The net can be hung on your balcony laundry bar, placed on your balcony, or hung anywhere outside your home. Do NOT hang inside.
Some variants of the mukade sprays also work against spiders (check the drawings on the spray to see if it works against spiders)
But for spider specific sprays there is this one
Bug Bombs (referred to as バルサン)
Varsan is the most common bug bomb in Japan which is sold in home stores or drug stores. If you have a lot of pests in your apartment, the easiest way to get rid of them is to bug bomb them. There are different types but water based and smoke bombs are popular. Its suggested to do this about twice a year.
However, you have to leave your apartment for 3 to 4 hours when you set it off
Please follow carefully the instructions below before using this insecticide.
1. First, close the windows and cover fire alarms and furniture items like the TV and your bed. Also wrap your clothing and tableware.
2. Place the product in the middle of the house and open the cap and use it to rub or press the middle part of the can as shown in the video. Smoke will come out.
3. Leave the apartment for 2 to 3 hours.
4. Clean the apartment by Vacuum cleaner. (source [x])
One last recommendation – for those of you who have tried all of this and still feel haunted by bugs, one JET came up with a rather creative solution: she sleeps with a mosquito net. It gives you peace of mind when you sleep, and you can usually find them in camping stores and/or sports stores with camping sections.