Location: Bioenergy Research
Project Number: 5010-41000-189-009-S
Project Type: Non-Assistance Cooperative Agreement
Start Date: Jul 24, 2022
End Date: Jul 23, 2023
Research Objectives: 1) In laboratory studies, produce four promising dry-tolerant Pseudomonas triculture formulations and track shelf-life and efficacy, incorporating best technologies developed FY17-21 --including fermenter production methods, carriers, osmoprotectants, surfactants, and rehydration techniques. 2) In one-ton bin studies, test performance of two most promising biocontrol (BCA) prototypes from laboratory studies across four cultivars at two Fusarium disease pressures under conditions typical of a commercial storage. 3) Test agrichemical compatibility and impact of potato storage conditions on BCA performance relative to a formulation of azoxystrobin and fludioxonil.
Objective 1) In this study, BCA triculture will be produced using four promising nutrient sources: two sugar sources (glucose versus switch grass hydrolysate) x two nutrient delivery methods (batch control versus optimized nutrient delivery). “Batch control” refers to batch cultivation on medium we have used successfully in past small pilot studies with the Cooperator prior to any optimization of nutrients or feeding method. Guided by previous ARS studies, harvested BCA tricultures will be formulated with osmoprotectant then air dried on a dispersible carrier, packaged, and refrigerated at 4 deg C. During storage several months, the product will be sampled for cell viability and biocontrol efficacy against dry rot using a wounded potato bioassay developed by ARS. Based on viable cell yield, shelf life and efficacy at lab scale, optimal treatments will be selected for Objectives 2 and 3 testing at Cooperator facilities. Objective 2) The two best dry BCA triculture treatments from Objective 1 will be rehydrated with surfactant and applied using appropriate spray equipment, BCA dose and volume in 1-ton bin studies at Cooperator’s facilities. Dry rot biocontrol efficacy will be tested against a “no BCA” control across 4 cultivars [Clearwater Russet (susceptible), Ranger Russet (susceptible), Russet Burbank (moderate), and Alturas (resistant)] at 2 Fusarium disease pressures during storage under industry-like conditions. Objective 3) The impact of two key storage temperatures (and/or disease levels, pending funds) on biocontrol by two BCAs (compared to a formulation of azoxystrobin and fludioxonil and no controls) will be assessed on Clearwater Russets in 1-ton bins. Additionally, considering the possibility of additive disease protection, the compatibility of BCA treatments for application with common agrichemicals (such as, phosphite, hydrogen peroxide/peroxyacetic acid, chlorine dioxide, difenaconazole, azoxystrobin and fludioxonil) will be addressed using a modified jar test to account for biocompatibility based on cell viability and sprayability. Information gained will indicate applicability of this technology, the efficacy achievable, and the logistics of use for dry rot control in the potato industry. Results will be published in peer-reviewed and extension outlets.