METHODS TO FACILITATE THE ADOPTION OF ALTERNATIVES TO METHYL BROMIDE SOIL FUMIGATION BY CALIFORNIA STRAWBERRY GROWERS
Physiology and Pathology of Tree Fruits Research
2012 Annual Report
1a.Objectives (from AD-416):
1) Evaluate methods to produce strawberry using the raised bed trough system. Work proposed here is focused on methods of disinfestation for the soil and substrate including fumigant and nonfumigant methods. We will also monitor substrate nutrient status.
2. Evaluate and demonstrate combinations of heat, fumigants and mustard meal or soil disinfestation.
1b.Approach (from AD-416):
The capacity of multiple non-fumigant technologies to control soilborne pathogens of strawberry will be assessed in field. Characteristics of the pathogen populations resident to field sites will be evaluated using trational and molecular-based methods.
This serves as the final report. This project relates directly to objective 1 of the associated in-house project, which seeks to determine the efficacy of soil amendments, including the use of Brassica seed meals, for the control of soil-borne plant diseases. Brassica juncea seed meal from various commercial and experimental sources were evaluated for the generation of allyl isothiocyanate (AITC), a biologically active chemistry that is generated in response to hydrolysis of seed meal containing glucosinolates after application to moist soil. A time course study demonstrated that the release of AITC in response to application of B. juncea seed meal to soil varied depending on the commercial source of the material even when the same cultivar was utilized. In addition, maximal AITC yield and overall AITC production similarly varied among seed meal source. It is plausible that these differences were a function of seed meal storage condition and processing, but it could also be due to annual or geographic weather or climatic differences which influence plant chemistry. These factors must be considered to obtain optimal function of chemical mechanisms that contribute to the pest and disease control qualities of Brassica juncea seed meal. Field trials were established in Ventura, California, to evaluate the efficacy of non-fumigant methods for the control of soil-borne pathogens in strawberry production systems. Brassica seed meal amendment, anaerobic soil disinfestation (ASD), and the integration of steam with Brassica seed meal all significantly improved yields relative to the no treatment control. In addition, ASD or Brassica seed meal integrated with steam were as effective as pre-plant soil fumigation for control of soilborne disease and increasing fruit yields in this system.