The odor emitted by stink bugs is generally disliked in Japan. However, in parts of Southeast Asia and Africa, the scent is sometimes utilized as a flavoring or condiment. Preferences regarding smell tend to vary far more between individuals and ethnic groups than preferences regarding taste. Yet, when these insects damage crops, they are treated as pests and exterminated. A major concern this year is the predicted mass outbreak of stink bugs. Of particular worry is the expected influx of rice stink bugs from areas surrounding paddy fields during July and August, when rice plants are heading. Rice stink bugs were a major pest for domestic rice farming until the 1950s. Damage dropped sharply from the 1960s onwards, partly due to the widespread use of chemical pesticides. However, around 2018, the damage became severe again across a region stretching from Kanto to Kyushu; by 2024, their presence had been confirmed in 37 prefectures.
Chemical pesticides are effective against rice stink bugs. The challenge, however, lies in the difficulty of using them for control immediately before harvest. Naturally, whenever a problem arises, people emerge with the ingenuity to solve it. Researchers from the “Biomanufacturing” Research Center at the National Institute of Advanced Industrial Science and Technology (AIST), the University of Electro-Communications, and Akita Prefectural University took on this challenge. Stink bugs harbor microorganisms within their bodies that supply nutrients lacking in their diet—a mechanism similar to how humans rely on gut bacteria to supplement nutrients or boost immunity. The research team discovered a pathogenic microorganism that mimics the stink bugs’ symbiotic microorganisms. This pathogen kills the specific microorganisms that produce the nutrients the stink bugs require. Consequently, the stink bugs are unable to obtain necessary nutrients and die within ten days. This approach holds promise as a new method for controlling stink bugs.
Researchers are developing a pest control method based on the discovery of a microorganism that kills the microbes living inside stink bugs. Taking this concept a step further opens up new possibilities. When plants have their leaves eaten, they release substances that attract parasitic wasps; drawn by these scents, the wasps parasitize the abundant caterpillars, thereby curbing the damage. It has also become possible for humans to artificially produce the defensive substances that plants naturally create. Professor David Baker of the University of Washington, who won the Nobel Prize in Chemistry in 2024, successfully synthesized an artificial protein named “Top7″—composed of 93 amino acids—in 2003. He created a protein that does not exist in nature. Theoretically, it is becoming possible to manufacture amino acid sequences that do not occur naturally. If we can rapidly predict unknown proteins and put them to practical use quickly, it will become possible to develop substances that suppress mass outbreaks of pests like stink bugs. Successfully creating such substances at will could represent a significant business opportunity.
