Wasabi Compound Fumigant Found to Be Effective against Fire Ants

A research group including Yoshiaki Hashimoto, Associate Professor, Institute of Natural and Environmental Sciences of the University of Hyogo and Senior Researcher, the Museum of Nature and Human Activities, Hyogo, has found that allyl isothiocyanate (AITC), a compound found in wasabi —Japanese horseradish, is effective when used to fumigate against red imported fire ants.

The study began following a scare in May 2017 when red imported fire ants, a designated invasive alien species, were found at the Port of Kobe in a shipping container originating from China—the first time they had been confirmed in Japan. It focused on safe, easy fumigation methods that were effective against the ants but did not use conventional chemical agents suspected of being harmful to health and the environment. AITC, which is a harmless, naturally occurring compound in wasabi, and which has insecticidal and sterilizing properties, fits the bill.

The findings were published on April 24, 2020, in Applied Entomology and Zoology, with the article appearing online first at springer.com.

A red imported fire ant in a petri dish lined with a sheet containing microencapsulated AITC.

Source: Yoshiaki Hashimoto, Hironori Sakamoto, Koichi Goka, Hiromi Asai, Masamitsu Yasoshima, Hui-Min Lin. “The effect of fumigation with microencapsulated allyl isothiocyanate in a gas-barrier bag against Solenopsis invicta (Hymenoptera: Formicidae)” (2020)

The study gauged the insecticidal effects of AITC on the ants using a simple fumigation method: worker ants were placed in a cardboard box which was put in a gas-barrier bag containing microencapsulated AITC pellets. The researchers found that 24 hours of fumigation with these pellets (50g pellets vapored into approx.250ppm concentration of AITC) was enough to kill all the ants in the box, and the results indicated that a sufficient concentration of AITC vapor for effective fumigation against red imported fire ants could be maintained for approximately two weeks.

The graph on the left compares the results of fumigation on red imported fire ants using the gas-barrier plastic bag method with and without microencapsulated AITC pellets. The graph on the right plots the concentration of AITC gas emitted over time by microencapsulated AITC pellets (50g in total) in a gas-barrier plastic bag.

Source: Yoshiaki Hashimoto, Hironori Sakamoto, Koichi Goka, Hiromi Asai, Masamitsu Yasoshima, Hui-Min Lin. “The effect of fumigation with microencapsulated allyl isothiocyanate in a gas-barrier bag against Solenopsis invicta (Hymenoptera: Formicidae)” (2020)

AITC is derived from wasabi—a condiment—and is used as a food preservative; no special materials or protective masks are required, and it does not soil or damage cargo. As such, it is hoped that AITC will be developed as a versatile, easy-to-use fumigant against red imported fire ants.

Further Reading
“The effect of fumigation with microencapsulated allyl isothiocyanate” at springer.com