Hot Alternatives Abound for Growers To Use in Place of Chemical Fumigants

By Thomas Skernivitz|October 14, 2022

There has long been a rally cry for alternatives to chemical fumigants in soil. Some voices are louder than others.

“This is a philosophical thing, and it may be controversial, but I’m going to say it anyway,” Steve Fennimore, an Extension Specialist with the University of California, Davis (UC Davis), says. “People have gotten too passive about pest management — soil pest management, above-ground pest management. We basically have depended upon the agricultural chemical industry to come up with pesticides. We’ve gotten passive — or maybe we always were passive.”

With a focus on soil health, Fennimore and other researchers in the U.S. and Canada are taking the offensive, in particular with three alternatives to chemical fumigants: soil steaming, anaerobic soil disinfestation (ASD), and biosolarization.

Having researched soil steaming the last 15 years in the Salinas Valley of California, Fennimore has become a major proponent of the technique, which uses steam to sterilize soil in open fields, high tunnels, and greenhouses. His hope is that growers, particularly on the vegetable side, become even bigger fans. He readily notes, as a disclaimer, that he is in the process of developing a steaming device; an endeavor he encourages growers to consider themselves.

“I work on crops like lettuce and broccoli and strawberries, and as far as weed control, which is one of the strengths of steaming, those are not markets [for machinery]. It’s not [the growers’] fault. It’s just a limitation of the system,” Fennimore says. “So, you ask about a take-home message for farmers: If you want to use this technique, you’re going to have to develop the technology yourself.”