Themis Michailides, a plant pathologist, led the research at UC's Kearney Agricultural Center near Parlier that looked into management practices to control aflatoxin, according to a news release.
He and fellow researchers discovered inoculated orchards with harmless Aspergillus flavus 36 (AF36), it displaced noxious Aspergillus flavus spores in orchards.
The fungal organism is a concern because it produces a toxin—aflatoxin—that can't be killed by heat, such as during roasting.
Aflatoxin has become a concern to nut growers in general because Europe will reject loads that exceed 10 parts per billion. The U.S. standard is 15 ppb.
The beneficial fungus was first investigated by Peter Cotty, a research plant pathologist at the University of Arizona.
He looked at it as a way to reduce aflatoxin in corn and cottonseed for animal feed.
Michailides and his group found that they could introduce the beneficial fungal spores into pistachio orchards by inoculating dead wheat seeds, then spreading the seeds on the orchard floor.
Dew and soil moisture spurred growth of the harmless spores, which then colonized pistachios and prevented colonization by the toxic strains.
The researchers are now expanding the research to almonds, where they hope to obtain an experimental use permit soon, and to figs.