Dec 04, 2013 - 07:01 AM
Anytime rice hulls are used as insulation, there is a large risk of getting an infestation of beetles that are commonly known as "food pests", "crop pests" with the single identifying beetle as (as you said) red flour beetles, confused flour beetles, etc.
If the walls have become infested, since there are rice hulls inside the walls, then total control may never occur, as you will be battling the infestation from time to time as the beetles emerge from the walls.
Here in the USA, I would normally recommend "tent fumigation" with Vikane. This is a process where the entire house is covered with fumigation tarps, and a lethal gas is fogged into the house. It then penetrates all walls, rice hulls, etc, killing everything. In Japan, I am not sure if anyone does this.
The only thing that I can recommend that you can do yourself, is to remove the wall switch plates and "dust the walls" and also any cracks, crevices, etc that you can find with an insecticidal dust such as Alpine. Alpine Dust is a "green" insecticide dust although not totally natural. A natural dust would be a product like Cimexa.
Basically you dust the walls with a hand type duster such as the Puffer Hand Duster. Spraying the baseboards and corners of rooms with a product such as Essentria could also provide some limited control. Essentria Dust is also available.
Persistence, routine treatments and possibly even using Sticky Traps such as the ePest IPM Trap are the only way to get control outside of fumigating the house.
Foggers, and just spraying something indoors won't work to control this beetle in this situation.
Yes we ship to Japan. I need your exact shipping address to get you a shipping estimate.
Hope this helps.