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Boars begone: Japanese firm creates 'burning'-scented crop-eating pest repellent

A bottle of "Guardest Pro" (left), which has an odor resembling that of a forest fire, is seen in Oamishirasato, Chiba Prefecture, on May 1, 2023. The bottle at right, used to set the animal repellent, is included with every purchase. (Mainichi/Yoshitaka Yamamoto)

CHIBA -- A foul-smelling liquid produced by an east Japan company is attracting attention as an effective way to guard farmers' assets from animal pests such as wild boars, deer and masked palm civets.

    The liquid, "Guardest Pro," released by Oamishirasato, Chiba Prefecture-based Office Try, is made from a byproduct of biomass energy generation. Its burnt odor repels the unwelcome animals which often feast on crops.

    The company's owner, 57-year-old Tomoyuki Tsuruga, used to be a resort hotel membership salesman. Wondering what to do next after quitting his job in February 2018, he heard about the issue of crops being devoured by wild animals from an acquaintance dealing with the issue. Just then, he remembered how wild boars were a major pest at resort golf courses, digging holes and tearing up the greens. So he set his mind to coming up with a solution.

    Even if chain-link and electric fences are installed, many farmers remain plagued by the animals. Tsuruga was given a hint when a farmer acquaintance told him that wild animals seemed to be put off when rice plants were burned after the crops are planted. His attention turned to the "burning" smell. After six months of research and surveys, he dropped by a business outside of the prefecture which was dealing with a different problem: the disposal of liquid byproduct from biomass power generation.

    The leftover liquid from burning wood chips contains no harmful substances, and does not have a significant impact on wildlife or the environment. Tsuruga got some of the liquid and extracted the substances responsible for the reek reviled by pests.

    The smell given off by the liquid is stronger than that of wood vinegar, which can be bought at hardware shops. Starting in 2019, its effectiveness was tested at about 80 locations around Japan where beasts often prove a bother, such as along railways and around golf courses. Around 90% of the feedback was positive, including responses like, "Boars have stopped coming around."

    "It's possible the harmful animals instinctually hate odors similar to forest fires. Even if only a little bit, I'd like to help producers that are worried about protecting their crops," Tsuruga commented.

    Guardest Pro is available in 500-millileter bottles for 3,300 yen (roughly $24) each, including tax. Since last year, it has been offered as a "hometown tax" gift option by the city of Oamishirasato, allowing people to get hold of it as a tax write-off.

    The product is for sale directly by the company, which can be reached in Japanese at 080-3083-6925. The product's website, currently also only in Japanese, can be found at

    (Japanese original by Yoshitaka Yamamoto, Chiba Bureau)

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