As the specter of climate change looms larger, sustainable and environmentally friendly alternatives for pest and pathogen control in agriculture are becoming increasingly imperative. Steam disinfestation, once an antiquated method overshadowed by chemical pesticides, is experiencing a resurgence due to heightened environmental concerns. Despite its historical use, there has been limited exploration of scaling up steam disinfestation for field applications in vegetable crops. Therefore, there is a central focus in this project to evaluate the efficacy of band steaming for disinfestation in spinach and lettuce fields in the Salinas Valley. This study seeks to advance the validation of banded steaming as a practical alternative to chemical fumigation by conducting a comprehensive assessment of vegetable productivity in lettuce grown in steamed soils versus non-steamed soils. The experiment utilized a custom-built steam applicator equipped with a low-pressure 1,000 kg/hour steam generator in Salinas, CA, during 2023. All research and trials were conducted at the Salinas Extension and USDA Center. In addition to evaluating efficacy of steam disinfestation for pest control, a preliminary evaluation of its impact on the soil microbiome was conducted on spinach and lettuce fields. Soil samples were collected before and after steam application, and crops were meticulously monitored for soil-borne disease and weed control, alongside yields at harvest. Preliminary results indicate effective weed control and lower pathogen pressure after steam treatments. Furthermore, the trials conducted from July 2023 to September 2023, involved verifying the performance of the steam applicator treatments, and assessing beneficial soil organisms using 16S sequencing in the spinach and lettuce fields. Through a thorough analysis of the outcomes derived from these trials, our objective is to offer in-depth insights into the overall efficacy of steam disinfestation and its potential implications for agricultural practices. This investigation is particularly focused on assessing its impact on the soil microbiome, the presence of pathogens, and its effectiveness in weed control.
