2026/02/26 by Erika Escalona-Barragan, Connel Ching’anda, John S. Rachuy +1 · 1 voice
Agricultural and Biological Sciences · Environmental Science · #Plant Disease Management Techniques #Composting and Vermicomposting Techniques #Turfgrass Adaptation and Management
paper · doi:10.21273/hortsci18948-25
openalex publication_date 2026/02/26 · openalex created_date 2026/02/27 · openalex updated_date 2026/06/26
Band steaming is an emerging sustainable technology for controlling weeds and soilborne diseases in horticultural crops. In California, lettuce production faces increasing challenges due to weed competition, soilborne pathogens, rising labor costs for hand weeding, and strict regulations on pesticide use. Injecting steam into the soil and raising the temperature to more than 70 °C for 20 min effectively reduces both weed seed viability and pathogen inoculum. However, the parameters for field band steaming are not well defined; for example, optimizing the steam injection width and depth is critical to achieving the desired treatment temperature for optimal reduction in weed seedbank viability and pathogen inoculum densities in commercial applications. The objectives of this study were to optimize steam injector width and depth for reducing weeds and pathogens in lettuce production, and to assess the effectiveness of band steaming in commercial lettuce systems. Experimental and commercial trials were conducted in 2022 and 2023, to evaluate injector width-by-depth configurations ranging from 5 to 10 cm wide and 5 to 15 cm deep. Data collected included soil temperature, weed densities, hand-weeding time, and pathogen densities. Average maximum soil temperatures following steam treatment ranged from 58 to 85 °C across treatments, with higher temperatures and longer heat retention observed in the deeper injector depth treatments. Band steaming reduced weed densities by 80% to 100% across treatments and reduced hand weeding time by at least 74% compared with nontreated controls. The 10 cm wide by 10 cm deep treatment in Trial 1 and the 12.7 cm wide by 12.7 cm deep treatment in Trial 2 had the lowest weed densities and shortest hand weeding times. In experimental fields, steam treatment reduced Pythium spp. densities by up to 100%. In commercial fields, steam treatment reduced Fusarium oxysporum spp. densities by 80% to 95% compared with nontreated controls. These results demonstrate that band steaming is an effective nonchemical alternative for managing weeds and soilborne pathogens in lettuce production, offering a practical solution for improving crop health and reducing reliance on chemical inputs.