Adapting Anaerobic Soil Disinfestation (ASD) as a Pre-Plant Non-Chemical Soilborne Disease Management Tactic for Use in High Tunnel Tomato Systems

View the project final report

Commodities

• Vegetables: tomatoes

Practices

• Crop Production: continuous cropping, high tunnels or hoop houses
• Education and Training: on-farm/ranch research
• Pest Management: biofumigation, cultural control, integrated pest management
• Production Systems: agroecosystems

Fresh-market tomatoes are increasingly being grown in high tunnels to extend the growing season, meet demand for local food, and to avoid disease due to extreme precipitation events. Because tomatoes are a high value crop, high tunnel growers have forgone crop rotations in favor of continuous cropping cycles. Such intensification leads to increased soilborne disease pressure which can impact yields. Soilborne disease identification is difficult because of the below-ground nature of the pathogens and symptoms that can be mistaken for other factors. If yield losses are attributed to soilborne disease, available chemical and non-chemical treatments are often not used due to expense, health or environmental concerns, and availability. Without a clear understanding about what is causing declines, growers will use grafted tomatoes or move to soilless systems, increasing production costs. Anaerobic soil disinfection (ASD) has been demonstrated as an effective pre-plant non-chemical treatment for control of soilborne diseases in many cropping systems including tomato. However, there is little information regarding the efficacy of ASD in Northeastern high tunnels systems. ASD combines the incorporation of organic amendments, flooding, and soil sterilization into a single tactic and elicits microbial changes that are antagonistic to soilborne pathogens. These changes are influenced by the organic amendment addition, soil temperatures, and treatment duration. This project seeks to identify soilborne pathogens in high tunnels, evaluate ASD using local carbon sources to manage soilborne pathogens, and determine the reapplication frequency that the tactic should be reapplied. Soilborne disease management recommendations will be generated through this work.

This project aims to address the gaps in our knowledge regarding soilborne pathogens that are affecting high tunnel tomato yields and looks to optimize ASD using locally available carbon sources as a targeted soilborne disease management tactic for use in protected culture systems. It also looks to gain an understanding of the rate that soilborne pathogens will recolonize soils post-ASD in order to generate soilborne disease management recommendations including re-application rates for growers. This will be accomplished by:

1. Identifying soilborne pathogens potentially limiting yields in high tunnel tomato production systems. Despite limited information on soilborne pathogens in high tunnel system, I hypothesize that soilborne pathogens known to detrimentally affect tomato production are present in high tunnel tomato production soils. Samples collected from high tunnels as part of the initial steps of this project will be prepared for sequencing in order to positively identify soilborne pathogens.
2. Evaluate locally available carbon sources as part of the ASD treatment for targeted suppression of soilborne pathogens identified as part of the first objective. I hypothesize that local carbon sources, including agri-waste products, will generate a range of suppressiveness against the previously identified soilborne pathogens. Greenhouse pot trials will be used to evaluate carbon sources in ASD for antagonistic effects against the most economically important soilborne pathogens identified.
3. Investigating the spatial and temporal recolonization of soil by economically important soilborne pathogens following ASD treatment. I hypothesize that ASD using locally available carbon sources will reduce soilborne pathogen inoculum in the soil but will not entirely eradicate the pathogen. Further, it is expected that when susceptible crops are continuously produced in the same soils, the same soilborne pathogens will again increase disease pressure to pre-treatment levels. Having an understanding of the recolonization rate of soilborne pathogens post-treatment will ensure more effectual soilborne disease management recommendations that include the re-application frequency of the soilborne disease management tactic.