Sprays formed that kill the source of cedar pollen allergies
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Natural fat and a fungal species could provide long-desired relief to millions of people during the annual hay fever season in a relatively inexpensive and less destructive way.
In two separate studies, researchers are attempting to kill as many male cedar flowers as possible before they can release their pollen for the sneezing and itchy season that starts in February in many parts of Japan.
Both methods require less labor, money and time than conventional countermeasures, such as cutting down forests or replacing cedar trees with a strain that releases less pollen.
Kaihei Koshio, a professor with the Tokyo University of Agriculture, has worked with a private company to develop a pollen scattering inhibitor derived from natural fat.
When the agent was sprayed on cedar trees with young flowers between summer and early autumn, only the male flowers died, and 90 percent less pollen was released the following spring, he said.
Koshio has been conducting trial-and-error experiments for more than 25 years.
In hopes of fixing pollen in a sticky liquid, he tried steeping male flowers in such substances as pine resin and alginic acid, a component of seaweed slime.
The pollen would not solidify, but the male flowers died when they were soaked in salad oil.
That effect was also confirmed in a field test when a solution containing a minute quantity of salad oil was sprayed on a cedar forest from a helicopter.
Koshio ended up developing a pollen scattering inhibitor containing a surfactant derived from natural fat as the main ingredient. He tested its effect and environmental impact at forestry experiment stations and had it officially registered as an agrochemical.
“The agent is friendly both to nature and to the human body,” the professor said.
Instead of a fat-derived component, researchers at the quasigovernmental Forestry and Forest Products Research Institute (FFPRI) are studying micro-organisms that kill male cedar flowers.
They set their sights on a fungal species called Sydowia japonica. A spray containing the fungi killed male flowers and reduced the pollen amount by more than 80 percent.
Research at more than 100 locations across Japan showed that the fungi inhabit broad areas from Hokkaido to Kyushu. Being native to the country, the fungi are expected to have little impact on plants other than cedars.
The scientists are currently studying effective methods for spraying the fungi.
Spraying a pollen scattering inhibitor is expected to be immediately effective.
“The use of an inhibitor could be a means that fills a niche between other sorts of measures,” said Hayato Masuya, chief of the FFPRI Microbial Ecology Laboratory and a member of the research team.
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