This decidedly modern approach to shiitake cultivation has made them locally famous (or notorious, depending on taste in music).
Initially, the brothers began playing the music simply because they liked it but soon began noticing that their shiitake were growing larger and thicker. They also claim this technique is backed up by research showing that mushrooms thrive when exposed to low-frequency sounds (such as the bass line in reggae).
So remember, gang—it's classical music for plants, reggae for mushrooms.
(This story was reported in Japanese in the February 8, 2007, online edition of the Japan Newspaper of Agriculture (Nihon Nogyo Shinbun), but by the day of this posting the article had been removed from the site. The Web, like life itself, is fleeting.)