California strawberry farmers have applied steam to fields as an alternative to chemical fumigants used to kill soil-borne diseases. While steam has been used for decades in greenhouses, researchers are working to adapt the technology to fields near the Pacific Coast. Strawberries are especially susceptible to soil diseases, and growers rely on fumigants for their crops. Experts say using a machine to inject steam into the soil before planting can kill key soil-borne diseases and weeds and improve crop productivity. The vast majority of strawberries grown in the United States come from California.