Project Number: 2094-21220-002-17-R
Project Type: Reimbursable Cooperative Agreement
Start Date: Oct 1, 2016
End Date: Aug 16, 2019
To address the priority areas of 1) developing non-fumigant management options as part of a systems-based integrated disease management strategy and 2) improving soil health by altering soil microbial community structure to favor beneficial microorganisms as a means to improve pest management in crops impacted by the loss of methyl bromide in the pre-harvest environment. We propose an integrated research and outreach project to evaluate mechanisms and environmental interactions underpinning disease suppression by anaerobic soil disinfestation (ASD) and brassica seed meals (BSM) to enhance grower adoption. The loss of methyl bromide and restrictions on fumigant use make development of non-fumigant disease control options critical for many fruit and vegetable production systems. ASD and BSM are non-fumigant techniques capable of suppressing many soilborne pests across a diversity of cropping systems; however, capacity to utilize these techniques for disease control with predictable outcomes is hindered by lack of knowledge concerning underlying mechanisms of action and environmental interactions with suppression of different pests. These practices provide disease control in part through selection of a microbial community that directly limits pathogen activity and a system that is resilient to pathogen re-infestation of soils. The fungal pathogen Fusarium oxysporum f. sp. fragariae, which causes Fusarium wilt of strawberry is not effectively controlled by ASD and is only partially suppressed by BSM amendment. In preliminary studies we have demonstrated that BSM used in concert with low rate fumigant application results in synergy that is more effective than full rate fumigation or BSM amendment alone. In addition, we have identified strawberry germplasm that possesses partial resistance to F. oxysporum f. sp. fragariae. As such, we propose to: 1) Examine the efficacy of ASD when integrated with varying levels of host resistance to F. oxysporum f. sp. fragariae , 2.) Examine the efficacy of a formulated Brassica Seed meal (BSM) amendment for control of Fusarium wilt when integrated with varying levels of host resistance to F. oxysporum f. sp. fragariae , 3.) Examine composition of the strawberry rhizosphere microbiome to determine whether cultivar response to soil treatments relates to differential microbial community structure as has been demonstrated in apple, 4.) Conduct field trials to assess integration of soil treatments (ASD or BSM) with plant resistance, with or without low rate soil fumigation.
The capacity of different control strategies and integrated methods for suppression of strawberry root infection by F. oxysporum f. sp. fragariae will initially be evaluated in greenhouse assays. The role of soil microbial transformations in response to soil treatments on host susceptibility to this pathogen will be determined by conducting rhizosphere microbial profiling using NextGen sequence analysis. The results of greenhouse trials will guide implementation of future field trials. Subsequent field trials will explore the integration of effective treatments identified in greenhouse trials with the use of reduced rates of soil fumigants. Efficacy of these treatments will be established by monitoring soil and root populations of soil-borne plant pathogens, monitoring plant health, and collection of marketable yield data.